ES2905643B2 - IN SITU IDENTIFICATION SYSTEM OF PETROLEUM PRODUCTS IN RESERVOIRS - Google Patents

Description

DESCRIPTION

IN SITU IDENTIFICATION SYSTEM OF PETROLEUM PRODUCTS

IN FIELDS

TECHNICAL SECTOR

This invention is useful in the oil industry and especially in the sector of the extraction of petroleum products in installations, deposits and/or oil prospecting, as well as in the sector of process monitoring in oil refineries and similar installations.

More particularly, the present invention refers to a system capable of identifying crude oil in situ and in real time in a deposit of petroleum products, that is, in the very location where said products are found.

One of the advantages of the system according to the present invention is, therefore, that it makes it unnecessary to have to transport samples of said petroleum products from the position of the reservoir, to a different location, so that they can be analyzed.

BACKGROUND OF THE INVENTION

Petroleum products, for example crude oils, are complex mixtures made up of liquid hydrocarbons and other components, such as dissolved volatile components, asphaltenes and resins (usually found in colloidal suspension), dispersed solids and even emulsified water. Consequently, the composition and specific distribution of hydrocarbons in a petroleum product can vary markedly from case to case.

Therefore, in order to decide which is the most appropriate use for an oil product present in a reservoir and manage it properly, it is very important to be able to identify and classify it based on its chemical composition and the specific distribution of the different hydrocarbons it consists of. Various methods are known in the state of the art for this purpose, as well as for being able to detect possible variations in the composition of the petroleum product during the exploitation of the reservoir.

Most of the state-of-the-art methods for identifying petroleum products are based on the fact that certain physical-chemical properties of said petroleum crudes, such as -for example- their refractive index, density, viscosity or absorption spectrum Optically, they vary depending on the petroleum product in question and the specific fractions of hydrocarbons and other components that are present in it.

The state-of-the-art methods most frequently used in the laboratory for the identification and classification of crude oil and other petroleum products are based on gas chromatography techniques, flame ionization detection and/or mass spectroscopy.

On the other hand, oil products are usually found in deposits (an expression that in this description includes -among others- wells, facilities and/or oil prospecting), located underground at great depths, usually greater than 1 km.

This means that the petroleum products accumulated there are subjected, in most cases, to extreme conditions: frequently the pressure is higher than 800 bars and the temperature is equal to or higher than 170°C.

The high temperatures, pressures and depths at which oil product deposits are found and the accessibility restrictions that these conditions impose, prevent the application of conventional methods -previously described- at the location of the deposit itself, to analyze oil products in situ. .

For this reason, in order to identify the petroleum products and determine the distribution of the hydrocarbons that are present in a petroleum product deposit, the most common thing is to extract a sample of said petroleum product and transport it later -so that it can be analyzed- to a place specialized, normally a laboratory, in which the environmental conditions are those of normal conditions: temperature close to room temperature (between 20 and 25 °C) and pressure close to atmospheric pressure (1.01 Bar).

Once there, the physical properties of the extracted sample are studied, such as its density, refractive index, viscosity, and optical behavior in order to identify the petroleum product and estimate the chemical composition of the different substances of which it is composed.

The fact of having to transport the sample to a different location entails, among others, the following disadvantages: it complicates the petroleum product analysis procedure, slows it down and increases the costs associated with it. In addition, during the transport of the sample, alterations of its content in volatile fragments may occur.

In view of these drawbacks, various in situ analysis systems for petroleum product reservoirs have been developed.

Thus, for example, there are several oil product analysis systems based on so-called "Ice Core Sensors". These systems use networks of sensors, in which each of These sensors are specifically designed to detect the optical fingerprint (in the mid and far infrared range) of predetermined chemical components. The intensity variation of said optical trace makes it possible to determine the concentration of the corresponding chemical compound.

However, a large part of the optical components used in said systems with ice core sensors (such as optical sources, detectors and optical fibers), are more expensive than usual, as they have to comply with special technical characteristics, which allow them to work correctly in the mid and far infrared range (that is, those ranges of the electromagnetic spectrum with a wavelength between 2,500 nm and 1,000 ^m). In fact, the price of such components is often on the order of four times higher than that of optical components designed to work in the visible spectrum.

Various petroleum product analysis systems based on Gas Retention Optical Sensor (also known by its acronym, GHOST) tools are also known. These Ghost systems are capable of detecting changes in the refractive index of a petroleum product sample to determine if the sample contains oil, gas, or water. To do this, they measure the difference in intensity of light at a specific wavelength reflected by the sample.

Ghost systems are only capable of differentiating whether the sample contains oil, gas or water, so it would be advantageous to develop more versatile petroleum product identification systems capable of inferring different characteristic physicochemical properties of said petroleum products.

Several systems based on ion-selective fiber (ISF) sensors are also known, which measure the specific concentration of chemical species that react with special fibers that are selective to certain ions. As in the previous case, it would be advantageous to develop more versatile petroleum product identification systems that are capable of classifying crudes, inferring their properties instead of only detecting certain chemical components.

Downhole fiber optic evanescent wave spectrometers are capable of measuring variations of the optical absorbance spectrum in the mid-infrared. To do this, they use an optical fiber as a transducer whose coating has been partially removed and which comes into direct contact with the sample of petroleum product to be identified.

A disadvantage of evanescent wave spectrometers is the low mechanical strength of their measuring elements which consist, as previously stated, of bare fiber optic cores.

Document WO201633199 describes a real-time control system for a fiber optic interferometer that can be used in remote exploration of oil wells. The systems described in said document are based on distributed acoustic sensor technology (also known by its acronym in English, DAS) and are designed to be able to measure acoustic energy distributed along an optical waveguide, by means of backscatter detection. Raleigh.

These systems based on DAS sensors make it possible to calculate the composition of a petroleum product located in a reservoir, as well as to estimate the proportion of crude oil in water. Said systems, like the other in situ analysis systems for oil product reservoirs of the prior art -described above- are designed to measure properties of crude oil accumulated at the bottom of an oil well exclusively during the drilling phase of said well. oil.

For this reason, in the technical sector of oil product analysis there is still a need to develop new in situ identification systems that are capable of operating continuously (in real time) and not only during the drilling phase. Likewise, it would also be advantageous to develop more versatile petroleum product identification systems, capable of inferring different characteristic physicochemical properties of said petroleum products, and providing them in real time.

Document US 200717400A discloses an opto-reflectometer intended for the detection of acoustic pressure waves that can be used for the detection of oil pockets. However, the devices described in this document have drawbacks similar to those already mentioned in relation to document WO201633199.

On the other hand, it is important to point out that in order for an in situ identification system for petroleum products to function properly, it must be able to withstand, as seen above, the difficult conditions of pressure, depth and temperature at which they are usually found. subjected to crude oil deposits, as well as their chemically aggressive nature.

Likewise, said identification system should be able to collect all the information necessary to carry out the identification with sufficient precision and transmit it, without excessive losses, to the system unit in charge of carrying out said analysis. Therefore, it is also desirable to improve crude oil identification procedures in order to obtain more reliable results.

In addition, it would be advantageous to develop an identification system capable of measuring in real time, continuously and not only during the drilling of the oil well.

On the other hand, in deposits of petroleum products, usually and as already anticipated, different components are present, forming two or more different phases. In fact, in most deposits it is common to find a combination of crude oil, gases and water. For this reason, it is necessary that the identification system be able to determine the compositions of crude oil, gas and water present in a deposit of petroleum products.

Various sensors are known in the state of the art to detect the presence or absence of chemical or biological substances in fluids, for example oils. Thus, for example, patent application WO2010/0066727 discloses a system for detecting the presence/absence of chemical or biological substances that comprises a translucent substrate, on which a plurality of objects configured to scatter electromagnetic radiation and provided with structures to generate a localized surface plasmonic resonance, a light source attached to an interrogation optical fiber and detectors.

The detection systems contemplated in said document WO2010/0066727 are intended mainly for biomedical applications (as mentioned, for example, on page 5, lines 14 to 22 of said document, as well as in all the examples given on pages. 20-21), a field remote from that of the present invention. In addition, said detection systems have not been designed, therefore, in such a way that they can withstand the extreme conditions of pressure, depth, and temperature to which crude oil deposits are usually subjected, as well as the chemically aggressive nature of said detection systems. petroleum crudes.

On the other hand, PCT application no. WO2005/088270 discloses sensors for monitoring dense fluids, for example oils. Said sensors are intended to be used in combination with an attenuated internal reflection apparatus (ATIR) comprising an evanescent wave sensor, a module to house said sensor and an optical connector to connect the sensor to the ATIR apparatus.

However, this sensor has not been designed to be able to withstand extreme conditions of pressure, chemical composition, depth and temperature to which oil product deposits are usually subjected.

Likewise, various photonic cells are known, used to optically analyze the physicochemical properties of different kinds of aqueous solutions, for example, resonant nano-pillar photonic cells and resonant layer-structured nanopore photonic cells. However, such photonic cells have not been used to date for the in situ identification of crude oil reservoirs.

Resonant nano-pillar photonic cells usually comprise a series of ordered nano-pillars where several thin layers are stacked according to a Bragg reflector structure which also includes a layer that acts as a resonant cavity.

As reported, for example, by Hernández AL et al in "Resonant Nanopillars Arrays for Label Free biosensing" Optics Letters 41(23), 5430, this distribution of layers, as well as the specific topography of the resonant nano-pillars, generate a pattern of interference in light whose position in wavelength depends on the refractive index of the medium in which the structures are submerged. As a result, the photonic cells of the resonant nano-pillars make it possible to detect changes in the refractive index of the fluids that fill the space between the nano-pillars.

On the other hand, nano-pores structured in resonant layers are disclosed -for example- in Manuel Oliva-Ramírez et al “Liquids Analysis with optofluidic Bragg Microcavities ACS Appl. Matter Interfaces” 2013, 5, 6743-6750. sayings Resonant layer-structured nanopores comprise a one-dimensional Bragg cavity made from a stack of porous layers, formed by oblique angle deposition. In a similar way to the previous case, in these photonic structures a change in the position of the resonant peaks occurs when the nano-pores are filled with liquids of different refractive indices.

Another type of spectroscopic technique is also known, called transreflection spectroscopy. In the case of NIR transreflection spectroscopy, the transduction systems are simpler and consist of a mirror that reflects light in that range of wavelengths and a light collection system. In general, for this purpose, metallic mirrors are used which, however, present considerable chemical reactivity that makes their degradation foreseeable in the corrosive environment within the deposits. An alternative recently reported in García-Valenzuela et al. "SiOx by magnetron sputtered revisited: Tailoring the photonic properties of Multilayers” in Appl. Surf. Sci. 2019, 488, 791-800 consists of manufacturing a Bragg mirror formed by stacking layers of SiO ₂ and SiOx (x<2 ) or Si that reflects in the NIR region and with considerable chemical stability under the working conditions of a crude oil reservoir.

DESCRIPTION OF THE INVENTION

In order to solve the problems and disadvantages described in relation to the prior art, a first object of the present invention refers to an in situ identification system for petroleum products in reservoirs, characterized in that it comprises:

i) a sensor unit provided with at least:

- a first transducer, of the resonant photonic type, comprising at least one photonic cell with resonant nano-pillars or at least one photonic cell with nano-pores structured in resonant layers, said photonic cell being configured to generate an interference pattern predetermined optical when an optical interrogation signal falls on them, said interference pattern being different when the cells are in contact with a petroleum product;

- a second transducer selected from

a) a transreflection photonic transducer comprising at least one transreflection mirror, said transreflection mirror being configured to come into contact with the petroleum product and to reflect at least a portion of the optical interrogation signal that has passed through the petroleum product ( known as transreflection optical signal); and

b) a radio frequency transducer, comprising a resonant circuit configured to resonate at a predetermined resonance frequency in the radio frequency range, said resonance frequency being different when the radio frequency transducer is in contact with a petroleum product;

ii) interrogation means, provided with an optical source configured to generate an optical interrogation signal with a predetermined spectrum of wavelengths;

iii) an analysis and identification unit configured to analyze at least:

a) the optical interference patterns generated in the photonic cells of the first transducer; and

b) the spectrum of the transreflection optical signal reflected by the transreflection mirror of the second transducer when a transreflection photonic transducer is used and/or the variation of the resonance frequency in the radio frequency range when a transreflection transducer is used. radio frequency;

the analysis and identification unit also being configured to identify the petroleum product present in the reservoir from the results of said analyses; and

iv) a multi-channel communication line comprising optical fibers and configured to:

a) transporting the interrogation optical signal, from the interrogation means to the sensor unit and to transmit the optical interference patterns in the form of an optical response signal, from the first transducer photonic cells of the sensor unit, to the analysis unit; and to

b) transmitting the transreflection optical signal reflected by the transreflection mirror of the second transducer to the analysis unit and/or transmitting radio frequency signals from the interrogation unit to the radio frequency transducer and from the radio frequency transducer to the interrogation unit .

The resonant nano-pillar (RNP) photonic cells for use in the present invention comprise at least one array of nano-pillars, said nano-pillars having an approximate diameter of the order of 200 nm and an approximate height of 1,900-2,200 nm and having the typical structure of a set of Bragg micro-cavities.

The nano-pore structured photonic cells (BMC) for use in the present invention are formed by stacking porous layers of two materials with a high refractive index (H), for example in the range of 1.7 1.8 and low (L) for example in the range of 1.2-1.3, with a thickness around 100 nm also defining a typical structure of Bragg reflectors. The structure is made up of two Bragg reflectors integrating a variable number of HL bilayers separated by a much thicker layer of L material, forming what is called an optical defect. The set, with a thickness of approximately 1000-1500 nm forms what is called a micro Bragg cavity.

The resonant nano-pillar photonic cells (RNP) and structured nanopore photonic cells (BMC) for use in the present invention preferably have a working range between 500 and 800 nm, which belongs to the spectrum visible.

Likewise, in the present invention each nano-pillar is preferably formed by an array of 10 multilayers. In turn, each multilayer is preferably formed by a series of alternating sheets of SiO ₂ (with a thickness of the order of 110 nm) and Si3N4 (with a thickness of the order of 97 nm). The resonant cavity in the middle of the pillar is also made of SiO ₂ , and is approximately 200nm thick.

On the other hand, the photonic cells, both RNP and BMC, have grown preferably on a 500 ^m thick quartz substrate.

It has been possible to verify that both the photonic cells of resonant nano-pillars and the photonic cells of nano-pores structured in resonant layers are capable of withstanding the difficult conditions of temperature, pressure, chemical composition and depth without appreciable deterioration. to which are usually found the deposits of petroleum products. Likewise, they can be used to analyze said petroleum products, without their performance being negatively affected by said adverse conditions.

Similarly, both transreflection photonic transducers (provided with at least one transreflection mirror) and radiofrequency transducers (provided with a resonant circuit in the radio frequency range) are equally capable of withstanding difficult temperature conditions, pressure and depth at which deposits of petroleum products are usually found.

In a preferred embodiment of the invention, at least one transreflection mirror of the transreflection photonic transducer is a near infrared (NIR) mirror, ie a device capable of reflecting electromagnetic radiation in the near infrared range. Likewise, the transreflection mirrors for use in the present invention preferably consist of a Bragg mirror formed by a stack of SiO ₂ and SiOx/Si layers.

Throughout the present invention, the near infrared (NIR) is considered to be that region of the electromagnetic spectrum whose wavelength is between 800 and 2,500 nanometers, being able to select the desired wavelength area within that range by modifying the structure of near-infrared (NIR) transreflection mirrors used in corresponding embodiments of the present invention.

Similarly, radio frequency (RF) is considered to be that region of the electromagnetic spectrum whose wavelength is between 10-3 and 108 meters, being able to select the desired wavelength area within that range.

The analysis unit of the identification system of the present invention is configured to analyze the optical interference patterns generated in the photonic cells of the first transducer. From this comparison, characteristic parameters of the petroleum product found in the reservoir can be obtained in real time, such as its refractive index, viscosity, density, composition (distribution of carbon chains), water content, and salinity.

Likewise, in those embodiments of the invention provided with a transreflection transducer, the analysis unit is also configured to analyze the spectrum of the transreflection optical signal (ie, the spectrum of the portion of the interrogation optical signal that is reflected by the transreflection mirror after reaching the petroleum product) and compare it with that of the initial interrogation optical signal. In this way, the system according to the present invention is capable of deducing the absorption spectrum of said petroleum product. From said optical absorption spectrum, relevant information can be deduced to identify the petroleum product, for example, about the distribution of carbon chains and functional groups of the hydrocarbons that are present in said petroleum product or the presence of other components such as particulate matter. in suspension, water or dissolved gases.

Finally, in those embodiments of the invention provided with a radio frequency transducer, the analysis unit is also configured to analyze the variation of the resonant frequency that occurs when the resonant circuit comes into contact with the petroleum product. From said comparison, characteristic parameters of the petroleum product found in the reservoir can be extracted, such as the distribution of carbon chains of the hydrocarbons that are present in said petroleum product, the density of the petroleum product, as well as the presence of water. .

Likewise, in those embodiments of the invention in which a radio frequency transducer is present: i) the interrogation means are provided -in addition- with a transmitter and a radio frequency receiver and ii) the multi-channel communication line is provided -in addition - of an RF waveguide configured to conduct radio frequency signals from the interrogation means to the radio frequency transducer and from the radio frequency transducer to the interrogation means.

Said transmitter is preferably configured to generate an adjustable tone in a predefined frequency range, belonging to the radio frequency (RF) region.

The combined use of a resonant photonic transducer with transducers of another type (transreflection photonic and/or radio frequency), contemplated by the system according to the present invention, allows a more robust analysis and identification of the petroleum product, since the information obtainable by each of them is complementary to each other. In addition, the petroleum product identification system according to the present invention is capable of operating continuously (ie, in real time) and not only during the drilling phase.

Preferably, the transreflection mirror of the transreflection photonic transducer is a mirror formed by stacking layers of a dielectric material such as SiO ₂ and a material selected from Si or SiOx, preferably with very low or zero x values to increase the difference between the refractive indices between the stacked layers. These materials are stable under the conditions of analysis of petroleum products that are the objective of this invention, surpassing in performance and stability the metallic mirrors commonly used in this type of structures.

Si, SiOx (0<x<<1) and SiO ₂ are transparent materials in the near-infrared region and the resulting stack behaves like a one-dimensional Bragg mirror due to the large difference in refractive index in the near-infrared region. NIR that exists between the SiO ₂ layers and the Si / SiOx layers (between 1.4 to 1,500 nm in the case of SiO ₂ and approximately 3.4 to 1,500 nm in the case of Si or SiOx for values of x close to zero , although in the latter case it can vary depending on its stoichiometry). Depending on the contrast between the refractive index and/or the thickness of the individual layers the stacks can be fabricated to selectively record predetermined regions of the NIR spectrum. Likewise, the stacks formed by Layers of these materials are capable of withstanding the difficult conditions of pressure, temperature and depth that oil product deposits are usually found in and also have high chemical resilience that allows them to be used for a long time to analyze oil products.

In a preferred embodiment of the invention, the transreflection mirror is a dielectric mirror formed by stacking layers of Si and SiO ₂ , the thickness of the different layers having been chosen so that said mirror works in the range of wavelengths between 800 nm and 1,700 nm.

Preferably, the radio frequency transducer for use in the systems according to the invention comprises:

- a sheet-shaped dielectric substrate, provided with two faces opposite to each other;

- a resonant circuit provided with electrically conductive strips, arranged on the first face of the dielectric substrate and configured to define a conduction line and at least two electrical resonators arranged symmetrically around the conduction line; and - a metallized coating, arranged on the second of the dielectric substrate;

a first end of the conduction line being arranged in open circuit and a second end connected to an electrical port configured to bring the conduction line to a predetermined electrical potential.

When this radiofrequency transducer is in operational mode, the line potential variations induce currents in one and the other resonator, establishing a resonance frequency of the transducer. The resonant frequency of said transducer depends on the extension and shape of the conductive strips, therefore, in the systems according to the present invention, These strips are sized in such a way that the transducer's own resonant frequency is within the radio frequency range.

On the other hand, if the environment surrounding the transducer and/or its physicochemical properties change, the resonance frequency of the transducer also changes accordingly, which allows it to be used for the identification of petroleum products.

Preferably, the electrical port is an SMA connector and the resonators comprise spirally arranged electrically conductive strips. Said spiral shape allows obtaining a more sensitive frequency response with smaller dimensions compared to other geometries.

The electrically conductive strips of the resonators are preferably made of copper. Likewise, said copper strips are preferably provided with an external gold coating, which prevents corrosion.

Also, the dielectric substrate is preferably a metamaterial comprising polytetrafluoroethylene (PTFE), glass fibers, and ceramic materials. An example of a possible ceramic material for use in the dielectric substrate described above is Rogers AD1000 (Trade Mark). A protective cover (eg Kapton) prevents contamination of the substrate by the sample.

For the purposes of the present invention, it is understood that a metamaterial is an artificial material that presents unusual properties (especially electromagnetic properties) that come from the designed structure and not from its composition, that is, said properties are different from those of its constituents.

The use of this type of metamaterials allows, on the one hand, said dielectric substrate to withstand the difficult conditions of pressure, chemical composition, depth and temperature to which oil product deposits are subjected and, simultaneously, said substrate has a relative permittivity of the order of 10, which facilitates its miniaturization.

Preferably, in the systems according to the present invention, the first transducer comprises the two types of photonic cells described above. In other words, the first resonant photonic transducer comprises at least one resonant nano-pillar photonic cell and at least one resonant layer-structured nanopore photonic cell.

In a preferred embodiment of the identification system according to the present invention the sensor unit is provided with the three different types of transducers already described. That is to say: i) resonant photonic transducers (with photonic cells of resonant nano-pillars and/or nano-pores structured in resonant layers); ii) transreflection photonic transducers and iii) radiofrequency transducers. And in which all the transducers act simultaneously in the manner already described above.

More particularly, in said specific embodiment of the present invention, the sensor unit is provided, at least, with:

- a first transducer, of the resonant photonic type, comprising at least one photonic cell with resonant nano-pillars or at least one photonic cell with nano-pores structured in resonant layers, said photonic cell being configured to generate a predetermined optical interference pattern when an optical interrogation signal falls on them, said interference pattern being different when the cells are in contact with a petroleum product;

- a second transreflection photonic transducer, comprising at least one transreflection mirror, said transreflection mirror being configured to contact the petroleum product and to reflect at least a portion of the interrogation optical signal that has passed through the petroleum product (known as a transreflection optical signal); and

- a third radio frequency transducer, comprising a resonant circuit, said circuit being configured to resonate at a predetermined resonance frequency in the radio frequency range, said different resonance frequency being when the radio frequency transducer is in contact with a petroleum product.

In addition, in this specific embodiment of the invention, the analysis unit configured to analyze:

- the optical interference patterns generated in the photonic cells of the first transducer;

- the spectrum of the transreflection optical signal reflected by the transreflection mirror of the second transducer; and

- the variation of the resonant frequency of said third transducer.

Likewise, in this specific embodiment of the invention, the multichannel communication line is also provided with an RF waveguide (which is precisely the one in charge of conducting the radiofrequency signals from the interrogation means to the radiofrequency transducer and from the radio frequency transducer to the interrogation means).

Finally, the multichannel communication line, in addition to optical fibers, also includes a radio frequency transmitter and receiver and is configured to:

- transporting the interrogation optical signal, from the interrogation means to the sensor unit and for transmitting the optical interference patterns in the form of an optical response signal, from the photonic cells of the first transducer of the sensor unit, up to the analysis unit;

- transmitting the transreflection optical signal reflected by the transreflection mirror of the second transducer to the analysis unit; and - conducting radio frequency signals from the interrogation unit to the radio frequency transducer and from the radio frequency transducer to the interrogation unit.

Preferably, the sensor unit comprises a support sheet on which the first transducer, the second transducer and, if present, the third transducer are arranged.

In a preferred embodiment of the invention, the sensor unit is provided with a sensor holder comprising:

- a holding region of the multichannel communication line, provided with ferrules with a hollow inner surface, configured to allow the passage through said hollow inner surface of the optical fibers of the multichannel communication line;

- a housing region of the multichannel communication line, configured to house the final portions of the optical fiber of the multichannel communication line, and

- a retention region of the support sheet of the sensor unit, configured to arrange said sensor unit adjacent to the final portions of the optical fiber of the multichannel communication line, the retention region further being provided with a configured hole to allow the passage of the petroleum product towards the sensor unit.

The sensor holder is preferably made, at least partly, of Teflon (polytetrafluoroethylene). This material allows working under high temperature conditions (up to 260°C), high pressure and in chemically aggressive environments.

It also has a low coefficient of friction (coefficient of static and dynamic friction Teflon on Teflon: 0.04) and a low resistance to compression (4-5 N/mm2 at 1% deformation, measured according to the ASTMD695 standard) therefore that can house components of the analysis system of the invention without damaging them and protect them from external mechanical stress.

Likewise, the sensor holder preferably comprises parts made of 316 stainless steel, for example hardware parts. This type of steel is preferred because it resists better than other steels (for example, 304 stainless steel) to high temperature and salinity conditions.

The optical fibers of the multichannel communication line are preferably protected by a protective coating, for example a polyamide coating. A 353 ND epoxy resin can also be used to seal the optical fibers inside the ferrules because this resin is more resistant to high temperatures than other resins.

Likewise, the multichannel communication line preferably comprises at least one bushing that is provided with:

- a cover, configured to couple tightly to an analysis probe or alternatively, to the mouth of an access hole to the petroleum product reservoir;

- at least one through hole, provided in the cover and configured to allow the passage of the optical fibers towards the sensor unit;

- at least one clamping means provided with:

i) a clamping bushing with a hollow inner surface that allows the passage of the optical fibers towards the sensor unit;

ii) fixing means, configured to fix the tightening bushing to an upper portion of the through hole; iii) a cap, configured to engage the top of the collet;

iv) at least one deformable element provided with a hollow interior surface that allows the passage of the optical fibers towards the sensor unit and arranged inside the clamping bushing, said deformable element being configured to deform when the cap is coupled to the clamping bushing. tighten and in such a way that it squeezes the optical fibers.

In a preferred embodiment of the invention, the clamping bushing fixing means comprise a thread made in a lower portion of the tightening bush and which is complementary to a thread made in the upper portion of the through hole.

The optical interrogation means are preferably provided with:

- an optical source, configured to generate an optical interrogation signal;

- at least one tunable filter, configured to limit the spectrum of the interrogation optical signal to a predetermined range of wavelengths;

- at least one optical coupler arranged after the tunable filter; and

- at least one emission multiplexer, configured to align the output of the coupler with the optical fibers of the multichannel communication line that carry the optical interrogation signal from the interrogation means to the sensor unit.

In a preferred embodiment of the invention, the optical interrogation means further comprise a beam splitter configured to divide the optical interrogation signal into two parts, a first part whose wavelength range is within the visible region and a second part whose wavelength range is within the visible region. second part whose wavelength range is in the near infrared. The beam splitter is preferably a dichroic mirror.

The analysis unit is preferably provided with:

- optoelectronic transduction means, configured to convert the response optical signal and the transreflection optical signal (if the system is provided with a transreflection photonic transducer) into electrical signals; and

- a programmable logic unit, configured to analyze at least:

a) the electrical signals corresponding to the response optical signal and, b) the electrical signals corresponding to the transreflection optical signal, or the variation of the resonance frequency.

The optoelectronic transduction means preferably comprise:

- a photodetector configured to work in the visible range of the electromagnetic spectrum;

- a photodetector configured to work in the near infrared range;

- a reception multiplexer configured to direct the response optical signal to the photodetector that works in the visible and to direct the transreflection optical signal to the photodetector that works in the near infrared.

The above indicated photodetectors preferably comprise at least one photodiode, configured to convert the corresponding optical signal (either the response optical signal, or the reflected interrogation optical signal), into electrical currents.

Likewise, the optoelectronic transduction means also preferably comprise:

- at least one amplifier, configured to convert the electrical currents created by the photodiode into electrical voltages, amplifying their magnitude; and

- at least one analog-to-digital converter (ADC), configured to convert the electrical voltages obtained in the amplifier into digital electronic signals.

BRIEF DESCRIPTION OF THE DRAWINGS

To complete this description of the invention and with the aim of helping to better understand the technical characteristics of the invention, in accordance with preferred examples of practical embodiments thereof, a set of instructions is attached as an integral part of said description. drawings where, with an illustrative and non-limiting nature, the following has been represented:

Fig. 1.- It is a schematic view and not to scale, of the main elements of which an analysis system according to the present invention consists;

Fig. 2A.- Is a front plan view showing a possible embodiment of the sensor unit for use in the analysis system according to the present invention;

Fig. 2B.- Is a perspective view of the sensor unit shown in Fig. 2A;

Fig. 2C.- Is a perspective view of a possible embodiment of a resonant photonic transducer, with photonic cells of resonant nano-pillars;

Fig. 2D.- Is a perspective view of a possible embodiment of a resonant photonic transducer, with photonic cells of nano-pores structured in resonant layers;

Fig. 2E.- Is a schematic view that shows a possible embodiment of a transreflection photonic transducer and its operating principle;

Fig. 2F.- Is a view of a set of transreflection mirrors that forms part of the transreflection photonic transducer of fig. 2E;

Fig. 2G.- Is a schematic plan view that shows an embodiment of a radio frequency transducer of the sensor unit;

Fig. 3A is a plan view showing an embodiment of the invention in which the analysis system comprises a sensor holder and a bushing;

Fig. 4A is a perspective view showing a possible embodiment of the feedthrough for use in the analysis system according to the present invention;

Fig. 4B shows two side sectional views of the transit of Fig. 4A;

Fig. 4C is a sectional view of a first embodiment of a gland for use in the test system of the present invention;

Fig. 4D is a sectional view of a second embodiment of a gland for use in the test system of the present invention;

Fig. 5 is a block diagram that schematically shows a possible embodiment of the invention, in which some of the most important elements that make up the identification system are shown;

Fig. 6A shows three SEM images (scanning electron microscope images) illustrating, respectively, a resonant nanopillar photonic cell, a resonant layer-structured nanopore photonic cell and a transreflection mirror, for use in the system of the invention;

Fig. 6B shows three graphs illustrating -respectively- the reflection spectrum of the resonant nanopillar photonic cell, the resonant layer-structured nanopore photonic cell and the transreflection mirror of Fig. 6A.

Fig. 7A shows the reflection spectrum obtained with a transducer provided with a resonant nanopillar photonic cell, for use in the present invention;

Fig. 7B shows the reflection spectrum obtained with a transducer equipped with a structured nano-pore photonic cell, for use in the present invention;

Fig. 7C shows the spectrum obtained with a radiofrequency transducer, for use in the present invention; and

Fig. 7D shows the reflection spectrum obtained with a transreflection optical transducer, for use in the present invention;

Numerical references of the Figures

(1) Reservoir of petroleum product;

(1a) Petroleum product;

(2) Gas bag;

(3) Orifice for access to the oil product deposit;

(4) Drilling tower;

(5) Drill pipe;

(10) Sensor unit;

(11) Resonant photonic transducer (of the sensor unit);

(IIA ) Resonant nano-pillar photonic cell (from the first transducer);

(IIB ) Photonic cell of nano-pores structured in resonant layers (from the first transducer);

(12) Transreflection photonic transducer (of the sensor unit);

(12a) Transreflection mirror (of transreflection photonic transducer);

(12b) Support (of the transreflection photonic transducer);

(12c) Ferrules (of the transreflection photon transducer);

(13) RF transducer (from sensor unit);

(13a) conduction line (from the RF transducer);

(13b) electrical resonators (of the RF transducer);

(13c) electrical port (of the RF transducer);

(14) Dielectric substrate (of the RF transducer);

(15) Quartz substrate (of the resonant photonic transducer);

(20) Means of interrogation;

(21) Optical source;

(22) Beam splitter;

(23) Tunable filter;

(24) Optical coupler;

(25) Emission multiplexer;

(30) Analysis and identification unit;

(31) Optoelectronic transduction means;

(32) Reception multiplexer;

(33a) Photodetector (visible spectrum);

(33b) Photodetector (NIR);

(34) Programmable logic means;

(35) Programmable logic unit;

(36) Analysis software;

(37) Databases;

(40) Multichannel communication line;

(40a) Optical fiber that carries the optical interrogation signal;

(40b) Optical fiber carrying the response/transreflected optical signal; (50) Sensor holder;

(51) Clamping region of the multi-channel communication line;

(51a) Coupler of fiber optic sections;

(52) Hosting region of the multi-channel communication line;

(53) Substrate retention region;

(56) Sensor holder plate;

(60) Grommets;

(61) Grommet cover;

(62) Through hole of the wall bushing;

(63) Clamping sleeve for optics;

(63a) Means for fixing the clamping bushing;

(64) Cap of the tightening bushing;

(65) Deformable element of the tightening bushing;

(66) Piece of brass;

(67) Grommet rubber gasket;

(68) Auxiliary Through Hole (for RF);

(69) Plastic part;

(70) Analysis probe; and

(71) Coaxial watertight connector.

DESCRIPTION OF A PREFERRED EMBODIMENT

Throughout this description, as well as in the attached figures, the elements that have the same or a similar function will be denoted with the same numerical references.

Fig. 1 shows, schematically, an analysis system according to the present invention. Said system is intended to analyze, in this particular embodiment, the content of an oil reservoir.

In the application example of the system of the invention illustrated in said Fig. 1, the oil field is provided with a drilling tower 4, by means of which an access hole 3 has been made to a field 1 of petroleum product 1a . Above said reservoir is provided a pocket 2 of natural gas in which the hydrocarbons and more volatile components of the petroleum product 1a are present. In addition, a drill pipe 5 has been arranged in the hole 3 through which the petroleum product is pumped to rise to the surface.

On the other hand, the analysis system of the invention consists of a sensor unit 10 that has been introduced through the access hole 3 until it comes into contact with the reservoir 1 of petroleum product. The sensor unit 10 is connected to the interrogation means 20 and to the analysis unit 30, through the multichannel communication line 40.

More particularly, the multichannel communication line 40 is connected at one of its ends to the sensor unit 10 and runs along the entire length of the access hole 3 to the location of the interrogation means 20 and of the unit 30. analysis, connecting by the second of its ends to said means 20 and to said unit 30.

In Figs. 2A and 2B a sensor unit 10 for use in an identification system according to the present invention is illustrated.

In the embodiment shown in said figures, the sensor unit 10 comprises three different types of transducers: a resonant photonic transducer 11, a transreflective photonic transducer 12 and a radio frequency transducer 13. Likewise, the resonant photonic transducer 11 comprises, in turn, several photonic cells 11A of resonant nano-pillars and several photonic cells 11B of nano-pores structured in resonant layers.

The transreflection photonic transducer 12 comprises, in this embodiment of the invention, as transreflection mirror 12a an assembly formed by four near-infrared (NIR) mirrors. Said set of mirrors 12a is not visible in Figs. 2A and 2B, since it is arranged on the internal face of the support 12b, but it can be seen in Fig. 2F. In addition, in Fig. 2E the different elements of which said transreflection photonic transducer 12 consists are shown in detail.

Similarly, the only element of the radio frequency transducer 13 that can be seen in Figs. 2A and 2B is the electrical port 13c. However, in Fig. 2G the different elements of which said radio frequency transducer 13 consists are shown in detail.

Shown in Fig. 2C is a possible embodiment of a resonant photonic transducer 11 for use in the analysis system of the present invention. In the embodiment shown here, said resonant photonic transducer 11 is mounted on a substrate 15 made of quartz. In the case illustrated here, the resonant photonic transducer 11 comprises resonant nanopillar photonic cells 11A.

In this particular embodiment of the invention, said resonant nano-pillar photonic cells 11A are square cells with a side of 1mm and are formed from a photolithography process.

Fig. 2D shows another possible embodiment of a resonant photonic transducer 11 similar to that of Fig. 2C, but in which the resonant photonic transducer 11 comprises resonant layer-structured nano-pore photonic cells 11B.

Fig. 2E schematically shows the operation of a transreflection photonic transducer 12 for use in the present invention. As can be seen in said figure, the transducer 12 is provided with a support 12b which which, in this particular embodiment of the invention, comprises two walls separated by an empty space accessed by the petroleum product 1a, when introducing the sensor unit 10 in the reservoir 1.

The inner face of one of said walls of the support 12b is provided with transreflection mirrors 12a which, in this embodiment of the invention, are of the near-infrared (NIR) type, while the other wall of the support 12b is provided with some splints 12c, each of said splints 12c being aligned with the center of one of the mirrors 12a. Furthermore, each of the ferrules 12c holds an optical fiber 40a and an optical fiber 40b of the multi-channel communication line.

The optical fibers 40a are responsible for transporting the optical interrogation signal, from the interrogation means 20, to the transreflection photonic transducer 12. As can be seen in the figure Fig. 2E, the interrogation optical signal passes through the empty space in which the petroleum product 1a of the reservoir is located, reaching the center of the corresponding transreflection mirror 12a. Said mirror 12a reflects it in the form of a transreflection optical signal which, traversing the small thickness of raw material between the mirror and the fiber, is transported through the optical fiber 40b to the analysis and identification unit 30.

In Fig. 2F an assembly formed by four transreflection mirrors 12a is shown, of the near-infrared (NIR) type, which forms part of the transreflection photonic transducer 12 shown in Figs. 2A, 2B and 2E.

A possible embodiment of a radio frequency transducer 13 of the sensor unit 10 is illustrated in Fig. 2G. Said transducer 13 comprises a dielectric substrate 14 which is made of a metamaterial comprising polytetrafluoroethylene (PTFE), glass fibers and ceramic material. Rogers AD1000 (trade mark). In addition, said figure shows the first face of the dielectric substrate 14 on which the resonant circuit is provided. No However, the dielectric substrate 14 has a second face, not visible in figure 2A, on which is arranged a metallic coating that acts as a ground plane.

The resonant circuit of the transducer 13 comprises a conduction line 13a and two spiral-shaped electrical resonators 13b arranged symmetrically around the conduction line 13b. In this particular embodiment of the invention, both the line 13a and the resonators are made from conductive strips of copper provided with an outer coating of gold.

When the resonant circuit of the transducer 13 comes into contact with a petroleum product, its resonance frequency changes (since it is related to the permittivity of said petroleum product). The present invention uses this particularity to extract information on the physical-chemical properties of the petroleum product accumulated in the reservoir.

One end of the conduction line 13a is open-circuited, while the second end is connected to an electrical port 13c which, in this embodiment of the invention, is a lead-tin-silver alloy solder. Said alloy has a melting point of around 300°C, which is higher than the temperature to which deposits of petroleum products are usually subjected.

The transducer 13 is preferably covered with a Kapton layer, intended to prevent the petroleum product from degrading or contaminating it.

Fig. 3A shows an embodiment of the invention in which the identification system comprises a sensor holder 50 and a bushing 60.

The bushing 60 shown in Figure 3A is provided with a cap 61 sealedly coupled to an analysis probe 70 . The cover 60 is provided with two through holes 62, through which the optical fibers 40a and 40b of the multi-channel communication line are passed.

In this particular embodiment of the invention, the optical fiber 40a is in charge of transporting the optical interrogation signal, from the interrogation means 20, to the sensor unit 10. On the other hand, the optical fiber 40b is in charge of transporting the response optical signal and the transreflection optical signal, from the sensor unit 10, which has already interacted with the petroleum product, to the analysis and identification unit 30.

The cable gland 60 is additionally provided with two clamping bushings 63. The upper part of each of the sockets 63 is provided with a cap 64 with a through hole. In addition, the bushings 63 have a hollow inner surface, so it is possible to pass each of the optical fibers 40a and 40b through the bushings 63 and connect them to the housing region 51 of the multichannel communication line, adjacent to the sensor unit 10.

Likewise, the bushings 63 are provided, on their inner surface, with deformable elements 65 with a hollow inner surface (not shown in Fig. 3A but visible in Figs. 4C and 4D), configured to deform when the cap 64 is pressed. against the clamping bushing 63 when inserting the optical fibers 40a and 40b. Upon deformation, the elements 65 press the optical fibers 40a and 40b against the inner surface of the clamping bushing, holding them in a fixed position.

In this particular embodiment of the invention, as can be seen in Fig. 3A, the sensor holder 50 is mounted on a stainless steel plate 56.

Said sensor holder 50 comprises a first region 51 for holding the multichannel communication line. In this particular embodiment of the invention, region 51 comprises two couplers 51a, with a hollow inner surface intended to optically couple together two sections of optical fibers 40a and 40b. The final sections of the optical fibers 40a and 40b reach the second of the regions of the sensor holder 50: the region 52 for housing the multichannel communication line. The housing region 52 is -in turn- adjacent to the third region that forms part of the sensor holder 50: the region 53 for retaining the substrate 15 of the sensor unit 10.

In the embodiment shown in Fig. 3A, the optical fibers have a 200 µm core and are sheathed with polyamide.

In Figs. 4A and 4B another possible embodiment of a bushing 60 according to the present invention is shown. Said bushing 60 is provided with all the elements already described in relation to the bushing visible in figure 3A. For this reason, said elements already mentioned, which have been identified using the same numerical references, will not be described in more detail.

In addition, the cover 61 of the transit 60 of Figs. 4A and 4B, it is provided with a rubber gasket 67 that allows it to be coupled tightly to the analysis probe 70. Said joint 67 would also allow the cover 61 to be coupled to a threaded joint or threaded element.

The transit 60 of Figs. 4A and 4B is also provided with an auxiliary hole 68 at the lower end of which is provided with a coaxial watertight connector 71. Said auxiliary hole 68 allows the connection of the RF transducer, which connects a coaxial cable to a copper end of the bushing through the inside, and with a different cable outside.

In Figs. 4C and 4D show two further possible embodiments of collet 63, for use in a system according to the present invention.

Said bushings 63 are provided with all the elements already described in relation to the bushings visible in figure 3A. For this reason, said elements already mentioned, which have been identified using the same numerical references, will not be described in more detail.

In addition, the clamping sleeve 63 of Fig. 4C is provided on its hollow inner surface with a deformable element 65, made of Teflon and whose inner surface is also hollow. Likewise, between the cap 64 and the deformable element 65 a piece 66 of brass is arranged.

In this way, when the cap 64 is pressed against the clamping bushing 63 when inserting the optical fibers 40a and 40b, the cap 64 pushes the brass piece 66 against the deformable element 65, exerting pressure on the latter until it is deformed by pressing the corresponding optical fibers, 40a and 40b, against the inner surface of the tightening bushing 63, so as to retain it in a fixed position.

The clamping bushing 63 in Fig. 4D is identical to that shown in Fig. 4C, except that a first plastic part 69 is also interposed between the brass part 66 and the deformable element 65. In addition, a second plastic part 69 is provided after the deformable element 65.

Fig. 5 shows, by means of a block diagram, a possible embodiment of the identification system according to the present invention. In said figure it can be seen that, firstly, the interrogation means 20 comprise an optical source 21, configured to generate an optical interrogation signal. In this particular embodiment of the invention, the optical source 21 is a laser light source with a bandwidth that covers both the visible region of the spectrum and the near infrared, for example, a supercontinuous laser such as the Fianium SC4x0 model. (Commercial brand).

The interrogation means 20 of the particular embodiment of the invention shown in Fig. 5 only contain optical elements that work in the range of the visible spectrum and NIR. However, and as already mentioned above, in those embodiments of the invention in which a radio frequency transducer 13 is present, the interrogation means 20, in addition to optical elements, are also provided with means for emitting and transmitting signals in the region of radio frequency (RF).

A beam splitter 22 divides the optical interrogation signal into two parts, a first part whose wavelength range is within the visible region (and which is intended to illuminate a resonant photonic transducer of sensor unit 10) and a second part whose wavelength range is in the near infrared (and which is intended to illuminate a transreflection photonic transducer).

Each of the beams obtained at the output of the beam splitter passes through a tunable filter 23, configured to limit the spectrum of the interrogation optical signal to a predetermined range of wavelengths, and through an optical coupler 24.

The output of the optical couplers is connected, in turn, to the emission multiplexer 25, which directs the optical interrogation signal coming from one of the optical couplers 24 to the optical fiber 40a of the multichannel communication line 40, connected to the transmission transducer. which sensor unit 10 is in operation at that particular time.

The operation of the tunable filters 23 is controlled, preferably, by means of a personal computer (PC) or other control means connected to the filters 23, for example, by means of a USB connection. Thanks to said programmable logic means, it is possible to select the wavelength ranges (A) that the tuneable filters 23 allow to pass.

To achieve this selection of A, each tunable filter 23 internally passes the optical signal coming from the source optics 21 by a grating of diffraction (g ra ting ) with an inclination with respect to the optical signal beam. The position of the diffraction grating with respect to the beam is precisely what determines the wavelength at which the filter will emit. In this concrete embodiment of the invention, each tunable filter 23 has internally incorporated two different diffraction networks re n tes and one or the other was used, depending on the range of the wavelength that you wish to select.

The ranges of wavelengths covered by each degree can be, for example, the following:

The interrogation optical signal, after having interacted in the transducers of the sensing unit 10 with the petroleum product, identifies r, comes out through the optic fibers 40 b, in the form of an optical response signal and in this particular case, in the form of an optical signal of transreflection (in the NIR range). The optical fibers 40 b conduct these optical signals of response of trans-reflection up to the unit 30 of analysis and identification o f p ro d u c ts p etro líferos .

Preferably, both the 40a optical fibers and the 40b optical fibers have a 200-gm core and a num- ber opening Erica 0.22.

Multianal communication line 40, in addition to optical fibers 40 a and 40b, are also pre fe r ib lely pro vis ted with connectors óp ticos des tin adjos ir ig ir cor rectamente s sig a s óp ticas a los diferentes semen tos de los que cons ta la parte óptica del sistema .

The optical response signal and the transreflection signal are conducted by optical fibers 40b to the optoelectronic transduction means 31 of the analysis and identification unit 30 . Once there, they pass through a receive multiplexer 32 that directs the optical response signal to a photodetector 33a (configured to work in the visible range of the spectrum) and that directs the transreflection signal to a photodetector 33b (configured to work in the visible range of the spectrum). NIR).

The photodetectors 33a, 33b comprise, in this particular embodiment of the invention, a photodiode that converts the received optical signals into electrical currents. Said electrical currents are preferably amplified and the resulting electrical voltages pass through an analog-to-digital converter to be converted into digital signals.

In this embodiment of the invention, the analysis and identification unit 30 further comprises a programmable logic unit 35 provided with programmable logic means 34 with at least one processing board.

The programmable logic means 34 receive the digital signals formed from the electrical currents generated by the photodetectors 33a, 33b, analyze them by means of software 37 and compare them with the values obtained with a series of reference values included in databases. data 37.

Fig. 6A shows three photomicrographs identified with the letters a), b) and c) that illustrate, respectively, a photonic cell 11A with resonant nanopillars, a photonic cell 11B with nanopores structured in resonant layers, and a transreflection mirror that works in the near infrared. Both the photonic cells 11A and the photonic cells 11B are part of a resonant photonic transducer, while the transreflective mirror is part of a transreflective photonic transducer, for use in the system of the invention.

Likewise, Fig. 6B shows the reflection spectrum corresponding to each of the sensor elements in Fig. 6A: the photonic cell 11A with resonant nanopillars, the photonic cell 11B with nanopores structured in resonant layers and the mirror of of transreflection. In this case, a heptane transmission spectrum is also included to show that a range of wavelengths that collect information on typical hydrocarbon bands can be between 1250 and 2000 nm. Other ranges are selectable by varying the topology of the SiOx-SiO ₂ stack used in the mirror.

A system similar to that illustrated in Fig. 5, described above, was used in various laboratory tests to identify different crude oils. The results of such tests are illustrated in Figs. 7A to 7D.

More particularly, to carry out said crude oil identification tests, a sensor unit 1 was used, comprising both resonant photonic transducers provided with photonic cells 11A of resonant nano-pillars (RNP) and photonic cells 11B of nano-pores structured in resonant layers. (BMC), such as transreflection photonic transducers 12 that -in this particular embodiment of the invention- work in the near infrared (NIR) and a last RF transducer 13.

Each of the resonant photonic transducers was accessed by the optical interrogation signal via a specific optical fiber 40a, while the RF transducer 13 was powered by its own power cable.

The following table summarizes the different transducers included in the sensor unit used:

The properties (density and viscosity) at different temperatures of the crude oil used in the tests are summarized below:

On the other hand, the distribution of the carbon chains [C x 1 -40] of said crude oil used before carrying out the tests is as follows i.e. nte:

For each of the previously described crude oils, flowing spectra were taken through each of the thirteen transducers, according to what is described below:

In each of the sets of spectra described above, those spectra that were typical with respect to the average spectra were eliminated (mean day ) of said together, as well as a filtering (smoothing) of them through a S av itz k y -G o la y filter of grade 3 and frame length of 11.

In the tests carried out, the identification system was used according to the present invention to determine the following parameters s of the crude oil to be analyzed: density, viscosity and carbon chains.

For this, the following transducers were used for the determination of one ovary of said parameters, as summarized in the table which follows:

In the tests carried out, the identification analysis unit was configured to first subject the spectra of the RNP 0 transducers , BMC 0 and NIR dispersion, to a process of reference.

Thus, each spectrum of RNP 0 and BMC 0 was divided by the spectrum of REF 0 obtained in the same number of measurements. For the NIR dispersion case, the spectrum obtained is divided by the base line of the same transducer. This baseline is always the same throughout the exper im en ta tio n and consists of the average of the NIR spectra ob tained for room mea surement. The Fig. 7 to shows the spectra obtained with the resonant nano-pillar (RNP) transducers.

In this embodiment of the invention, the analysis and identification unit is configured to, starting from a clean data set for the spectra obtained by the RNP 0 transducer, apply principal component analysis (PCA), obtaining 3 principal components (PC). , which explain 87.7, 5.7 and 3.3% of the experimental signal.

To the transformation generated by PCA on the spectra, the analysis and identification unit incorporates labels relative to the corrected density with respect to the temperature value for each crude oil.

With this information, the analysis and identification unit trains an exponential regression algorithm, obtaining the following precision:

-Mean square error (RMSE): 0.01

- AR2: 0.94;

- MSE: 0.00;

- MAE: 0.00.

The analysis and identification unit then proceeds to infer the density of the "problem" crude oil under test (taking into account the temperature during its measurement). Thus, it obtains the following root mean square error (RMSE) metrics by comparing the predicted value with the real:

Similarly, to determine the viscosity of the "problem" crude oil under test, the analysis and identification unit starts from a con to junto de dato s lim p io para los spectro sobre obtenidos osporeltra nsduc tor RNP 0, y ap lic aan alisis decomponente spr in c ip a le s (PCA ), obten ie Using 3 PCs, which explained 87.7, 5.7 and 3.3% of the expe rim en ta l signal.

To the transformation generated by PCA on the spectra, the analysis unit and identifi cation incorporates labels rela tive to the v is c o s ity corrected with respect to the value of temperature for each crude oil.

With this information, the analysis and identification unit trains an exponential regression algorithm (regression process n G aus ia n a , G P R ) obtaining the following precision:

- Mean square error R M S E: 7.86;

- RA2: 0.84;

-MS E: 57.14;

- M A E : 2.06.

The analysis and identification unit then passes to infer the viscosity of the crude oil "problem" object of assay (has taking into account the temperature during its measurement) Thus, the following mean square error metrics are obtained ( R M SE ) comparing the predicted value with the actual value:

The Fig. 7B shows the spectra obtained with the nano-pore transducers (BMC).

In this embodiment of the invention, the analysis and identification unit is configured for, starting from a set of data clean for the spectra obtained from the transducer BMC 0, they will apply spr in c ip a le com ponent a lysis (PCA ), obtaining 1 pr in com ponent c ip al, which explains 98.2 % of the exper im en ta l signal.

To the transformation generated by PCA on the spectra, the analysis unit and identifi cation incorporates labels rela tive to the corrected density with respect to the temperature value for each crude oil.

With this information, the analysis and identification unit trains an exponential regression algorithm, obtaining the following ie n te precision:

- R M S E : 0.00 ;

-R A2: 1.00;

-MSE: 0.00;

- M A E : 0.00.

The analysis and identification unit then proceeds to infer the density of the crude oil "problem" under test (taking into account Thus, you obtain the following metrics of root mean square error (RMSE) by comparing the p value re said with the real:

In a similar way, to determine the viscosity of the crude oil "problem" object of test, the análisis unit is and iden tyf ication part of a clean data set for the spectra obtained by the transducer BMC 0, and apply principal component analysis s (PCA), obtaining 1 PC, which explain 98.2% of the experimental signal.

To the trans fo rm atio n generated by the PCA on the spectro s, the analy sis an id en tif ica tio n unit incor porates a rela tive tags the v is co sity corrected with respect to alva lo rde tempera ture for cadac ru do.

With this information, the analysis and identification unit trains an exponential regression algorithm, obtaining the following precision:

- RMSE: 0.78663

- RA2: 1.00

- MSE: 0.61879

- MAE: 0.49063

The analysis and identification unit then proceeds to infer the viscosity of the "problem" crude under test (taking into account the temperature during its measurement). Thus, it obtains the following metrics of root mean square error (RMSE) comparing the predicted value of the real :

Fig. 7C shows the spectra obtained by the radio frequency (RF) transducer.

In this embodiment of the invention, the analysis and identification unit is configured to, starting from a clean data set for the spectra obtained by the RF transducer, apply principal component analysis (PCA), obtaining 3 PC's, which explain the 52 0.6, 29.5 and 12.9% of the experimental signal.

To the transformation generated by PCA on the spectra, the analysis and identification unit incorporates labels relative to the corrected density with respect to the temperature value for each crude oil.

With this information, the analysis and identification unit trains a linear regression algorithm (linear iterations), obtaining the following precision:

- RMSE: 0.01;

- AR2: 0.96;

- MSE: 0.00;

- MAE: 0.00.

The analysis and identification unit then proceeds to infer the density of the "problem" crude, obtaining the following metrics of root mean square error (RMSE) comparing the predicted value of the real one:

Fig. 7D shows the spectra obtained by the transreflection transducer which, in this embodiment of the invention acts in the near infrared (NIR 0).

To infer the distribution of carbon chains from these spectra, the analysis and identification unit starts from a clean data set for the spectra obtained by the NIR transducer and applies principal component analysis (PCA), obtaining 3 principal components that explain 73.5, 17.7 and 5.5 % of the experimental signal.

To the transformation generated by PCA on the spectra, the analysis and identification unit incorporates labels relative to the distribution of carbon chains for each of the previously defined groups (not including the raw "problem" that will be inferred).

The analysis and identification unit trains a linear regression algorithm (linear iterations) for the first group Cx_1_5, obtaining the following precision values:

- RMSE: 0.59;

- AR2: 0.91;

- MSE: 0.35;

- MAE: 0.41.

For the second group Cx_6_10 a similar methodology is used, obtaining:

- RMSE: 0.88;

- AR2: 1.00;

- MSE: 0.78;

- MAE: 0.57.

For the third group Cx_11_15 a similar methodology is used, obtaining:

- RMSE: 0.33;

- AR2: 0.99;

- MSE: 0.11;

- MAE: 0.25.

For the fourth group Cx_16_20 a similar methodology is used, obtaining:

- RMSE: 0.28;

- AR2: 0.99;

- MSE: 0.08;

- MAE: 0.21.

For the fifth group Cx_21_25 a similar methodology is used, obtaining:

RMSE: 0.20;

- AR2: 0.99;

- MSE: 0.04;

- MAE: 0.15.

For the sixth group Cx_26_30 a similar methodology is used, obtaining:

- RMSE: 0.18;

- AR2: 0.99;

- MSE: 0.03;

- MAE: 0.14.

For the seventh group Cx_31_35 a similar methodology is used, obtaining:

RMSE: 0.13;

- AR2: 0.99;

- MSE: 0.02;

- MAE: 0.10.

For the eighth group C x _ 35 _ 40, a similar methodology is used, obtaining:

- R M S E : 0.09

-R A2: 0.99

- M S E : 0.01

- M A E : 0.07

Once the eight models have been generated, the analysis and identification unit infers the distribution of carbon chains or the crude oil problem. Thus, the following mean square error metrics (RMSE) are obtained by comparing the predicted value with the actual value:

To infer the presence of water in the analysis and identification unit, I use the spectra obtained by the radio-frequency transducer c o n c e n t r i o n s of Crude D agua of 1.6805%, 3.6568%, 8.5188%, 23.0593% and unknown (among the values 8.5188%, 23 .0593%).

Said unit of analysis and identification applies analysis of main components (PCA ), using all available spectra There are 3 main components that explain 68.5, 18.8 and 10.0% of the experimental signal.

Subsequently, the spectro salesspace defined by PCA are transformed and the cases 1.6805%, 3.6568%, 8.5188% and 23.0593% pa are used. ra train the intelligence system through linear regression, obtaining the following precision:

RMSE: 0.82;

- AR2: 0.99;

- MSE: 0.67;

- MAE: 0.62.

The analysis unit proceeds to predict the crude problem (using the previously obtained PCA coordinates) obtaining:

The system according to the present invention can optionally combine the results obtained by various different transducers to improve the accuracy and robustness of the predictions of the corresponding physical-chemical magnitudes of the petroleum products to be analyzed.

Thus, for example, to infer the density of the corresponding petroleum product with greater precision, the analysis unit can use the results obtained by several RNP resonant photonic transducers of which the sensor unit consists.

In the example shown in connection with Figs. 7A to 7D the unit of analysis can generate, for example, models for the prediction of density for RNP 1 and RNP 3. The model for RNP 1 was generated using an exponential regression algorithm and 1 principal component (97.5%), getting the following precision:

- RMSE: 0.01;

- AR2: 0.88;

- MSE: 0.00;

- MAE: 0.01.

The prediction for the crude problem was as follows:

The model for RNP 3 was generated using an exponential regression algorithm and 2 principal components (93.4%, 5.7%), obtaining the following precision:

- RMSE: 0.00;

- AR2: 1.00;

- MSE: 0.00;

- MAE: 0.00.

With these data obtained by the RNP transducers, it is possible to develop a fusion system that, based on the level of confidence in the generated model, provides a joint response of the RNP transducers. In this case, the confidence level can be defined as the RA2 value obtained during the training process. Thus, the joint response is governed by:

where U esityRm „ is the average value predicted by the density model at RNP 0 and ^R 2 ^Rflp oo is the RA2 value obtained during the training phase for the density model at RNP 0. The definitions for ^{D esidddRNp 1} , uensid.ad.PNP3 ^, R2 ^{pnpi , and} R2 ^pnp 3 follow the model given for UñsidadRNP o ^and R¿ ^{rnp o .}

Using this formulation, the analysis and identification unit obtains the following results:

Similarly, the system according to the present invention can optionally combine the results obtained by different transducers. tors RNP and/or BMC to improve the precision and robustness of the predictions corresponding to viscosity.

The analysis and identification unit can also be configured in such a way that it combines the results obtained from different BMC transducers. yes imitate the one described above to more accurately infer the viscosity

The present invention is not limited, in any way, to the embodiments disclosed herein. For the person skilled in the art, it will be obvious other pos s ib le realizations di erent of this invention, in view of the present description. Consequently, the scope of protection of the present invention is defined, exclusively, by the claims that follow n a c o n tin u a tio n .

Claims (15)

1. In situ identification system for petroleum products in deposits (1), characterized by the fact that it includes: i) a sensor unit (10) provided, at least with: - a first transducer (11), of the resonant photonic type, comprising at least one photonic cell (11A) of resonant nano-pillars or at least one photonic cell (11B) of nano-pores structured in resonant layers, each one of them being said photonic cells (11A, 11B) configured to generate a predetermined optical interference pattern when an interrogation optical signal falls on it, said interference pattern being different when the cells (11A, 11B) are in contact with a petroleum product; - a second transducer selected from: a) a transreflection photonic transducer (12) comprising at least one transreflection mirror (12a), said transreflection mirror being configured to come into contact with the petroleum product and to reflect a transreflection optical signal that has passed through the petroleum product ; and b) a radio frequency transducer (13), comprising a resonant circuit (13a, 13b, 13c) configured to resonate at a predetermined resonance frequency in the radio frequency range, said resonance frequency being different when the transducer (13 ) of radiofrequency is in contact with a petroleum product; ii) interrogation means (20), provided with an optical source (21) configured to generate an optical interrogation signal with a predetermined wave spectrum; iii) an analysis and identification unit (30) configured to analyze at least: a) the optical interference patterns generated in the photonic cells (11A, 11B) of the first transducer (11); and b) the spectrum of the transreflection optical signal reflected by the transreflection mirror of the second transducer (12) or the variation of the resonant frequency in the radio frequency range of said second transducer (13); the analysis and identification unit (30) also being configured to identify the petroleum product present in the reservoir (1) based on the results of said analyses; and iv) a multichannel communication line (40) comprising optical fibers (40a, 40b), being configured at least for: a) transporting the interrogation optical signal from the interrogation means (20) to the sensor unit (10) and for transmitting the optical interference patterns in the form of a response optical signal, generated in the photonic cells (11A, 11B ) from the sensor unit (10), to the analysis and identification unit (30); and to b) transmit the transreflection optical signal reflected by the transreflection mirror of the second transducer (12) to the analysis and identification unit (30), or to conduct radio frequency signals from the interrogation means (20) to the transducer (13). ) of radio frequency and from the transducer (13) of radio frequency to the means (20) of interrogation. Identification system according to claim 1, in which at least one transreflection mirror (12a) of the photon transreflection transducer (12) is a near-infrared mirror. 3. Identification system according to claim 1, wherein - the second transducer is a radiofrequency transducer (13), - the interrogation means (20) are also provided with a radio frequency transmitter and receiver; - The multichannel communication line (40) is also provided with a radio frequency waveguide configured to conduct radio frequency signals from the interrogation means (20) to the radio frequency transducer (13) and from the transducer (13). ) of radio frequency to the interrogation means (20). 4. Identification system according to any of the preceding claims, wherein: the sensor unit (10) is provided with: - a first transducer (11), of the resonant photonic type, provided with at least one photonic cell (11A) of resonant nano-pillars or at least one photonic cell (11B) of nano-pores structured in resonant layers; - a second transducer (12), of the transreflection photonic type, comprising at least one transreflection mirror (12a); and - a third transducer (13), radiofrequency; in which the analysis and identification unit (30) is configured to analyze: - the optical interference patterns generated in the photonic cells (11A, 11B) of the first transducer (11); - the spectrum of the transreflection optical signal reflected by the transreflection mirror (12a) of the second transducer (12); and - the variation of the resonance frequency the range of the radio frequency of the third transducer (13); wherein the interrogation means (20) are further provided with a radio frequency transmitter and receiver; and in which the multichannel communication line (40) comprises, in addition to optical fibers, a radio frequency waveguide and is configured for: - transporting the interrogation optical signal from the interrogation means (20) to the sensor unit (10) and for transmitting the optical interference patterns in the form of an optical response signal, from the photonic cells (11A, 11B) of first transducer (11) of the sensor unit (10), up to the analysis and identification unit (30); - transmitting the transreflection optical signal reflected by the transreflection mirror of the second transducer (12) to the analysis unit; and - conducting radio frequency signals from the interrogation means (20) to the radio frequency transducer (13) and from the radio frequency transducer (13) to the interrogation means (20). 5. Identification system according to any of the preceding claims, in which the first transducer (11) is provided with at least one photonic cell (11A) with resonant nano-pillars and at least one photonic cell (11B) with nano-pores. structured in resonant layers. 6. Identification system according to any of the preceding claims, in which the radiofrequency transducer (13) is provided with: - a dielectric substrate (14) in the form of a sheet, provided with two faces opposite to each other; - a resonant circuit (13a, 13b, 13c) provided with electrically conductive strips, arranged on the first face of the dielectric substrate (14) and configured to define a conduction line (13a) and at least two electrical resonators (13b) arranged symmetrically around the conduction line (13a); and - a metallized coating, arranged on the second face of the dielectric substrate (14); a first end of the conduction line (13a) being arranged in open circuit and a second end connected to an electrical port configured (13c) to bring the conduction line (13a) to a predetermined electrical potential. System according to any of the preceding claims, in which a sensor holder (50) is provided, comprising: - a region (51) for holding the multichannel communication line, provided with ferrules with a hollow inner surface and configured to allow the passage through said hollow inner surface of the optical fibers (40a, 40b) of the line (40) multichannel communication; - a region (52) for housing the multichannel communication line (40), configured to house the final portions of the optical fiber (40a, 40b) of the multichannel communication line (40), and a retention region (53) of the support (15) for holding the sensor unit (10), configured to arrange said sensor unit (10) adjacent to the end portions of the optical fiber (40a, 4b), being provided In addition, the substrate retention region (53) has an opening configured to allow the passage of the petroleum product towards the sensor unit (10). System according to claim 5, in which the sensor holder (50) is made, at least partially, of Teflon. System according to any of the preceding claims, in which the multichannel communication line (40) comprises at least one bushing (60) provided with: - a cover (61), configured to couple tightly to an analysis probe (70) or alternatively, to the mouth of an orifice (3) for access to the reservoir (1) of petroleum product; - at least one through hole (62), provided in the cover (61) and configured to allow the passage of the optical fibers (40a, 4b) towards the sensor unit (10); - at least one clamping means provided with: i) a clamping bushing (63) with a hollow inner surface that allows the passage of the optical fibers (40a, 4b) towards the sensor unit (10); ii) fixing means (63a), configured to fix the clamping bushing to an upper portion of the through hole; iii) a cap (64), configured to engage the top of the clamping bushing (63); and iv) at least one deformable element (65) provided with a hollow inner surface that allows the passage of the optical fibers (40a, 40b) towards the sensor unit (10) and arranged inside the clamping bushing, said deformable element being configured to deform when the cap (64) engages the clamping bushing (63) and so as to clamp the optical fibers (40a, 40b). System according to any of the preceding claims, in which the optical interrogation means (20) are provided with: - an optical source (21), configured to generate an optical interrogation signal; - at least one tunable filter (23), configured to limit the spectrum of the interrogation optical signal to a predetermined range of wavelengths; and - at least one optical coupler (24) arranged after the tunable filter (23); and - at least one emission multiplexer (25), configured to optically align the output of the optical coupler (24) with the optical fibers (40a) of the multichannel communication line (40). System according to claim 9, in which the optical interrogation means (20) further comprise a beam splitter (22) configured to divide the optical interrogation signal into two parts, a first part whose wave spectrum is within the visible region and a second part whose wave spectrum is in the near infrared. System according to claim 10, in which the beam splitter (22) is a dichroic mirror. System according to any of the preceding claims, in which the analysis unit (30) comprises: - optoelectronic transduction means (31), configured to convert the response optical signal into electrical signals; and - a programmable logic unit (35) configured to analyze: a) the electrical signals corresponding to the optical response signal; and b) the electrical signals corresponding to the transreflection optical signal, or the variation of the resonance frequency. System according to claims 2 and 13, wherein the optoelectronic transduction means (31) are further configured to convert the reflected interrogation optical signal into electrical signals and the programmable logic unit is further configured to analyze the electrical signals corresponding to the transreflection optical signal. System according to claim 14, in which the optoelectronic transduction means (31) comprise: - a photodetector (33a) configured to work in the visible range of the electromagnetic spectrum; - a photodetector (33b) configured to work in the near infrared range; - a reception multiplexer (32) configured to direct the response optical signal to the photodetector (33a) and to direct the transreflection optical signal to the photodetector (33b).