CN115437014A - A logging device based on flexible detector multi-dimensional imaging - Google Patents

Abstract

The invention discloses a logging device based on flexible detector multi-dimensional imaging, and belongs to the technical field of oil and gas exploration. The invention comprises a shell, wherein a main control board, a motor, an X-ray generator unit, a transformer, an X-ray flexible detector, a photoelectric conversion circuit, a data storage unit and a voltage stabilizer are sequentially connected in the shell. According to the invention, after the flexible X-ray detector is adopted to replace the traditional flat panel detector, the occupied area of the detector is reduced, and the acquisition of X-ray energy of the object with irregular radian is improved.

Description

A logging device based on flexible detector multi-dimensional imaging

technical field

The invention belongs to the technical field of oil and gas exploration, and relates to a logging device based on flexible detector multi-dimensional imaging.

Background technique

In X-ray backscatter imaging: X-rays have energy that cannot be optically focused, and are not affected by the density of matter when transmitted. The refraction of the oil mixture is very beneficial for downhole use. A beam of X-rays is collimated to form a narrow beam that produces a fine spot illumination on the target object, and data collection is achieved by a detector array system. Both the X-ray source and the detector are located on the same side of the object being probed, and the photons then pass through the barrier, scatter from the object, pass through the barrier again and enter the detector. The contrast in an X-ray backscatter image comes from the difference in the number of photons scattered by the object of interest versus the background object. Backscatter imaging works best when the object of interest scatters strongly and the background material does not scatter, such as in air. metal or organic objects. The traditional evaluation and inspection process of mineral debris formation, microbiologically induced corrosion and material defects in wellbore and downhole casing is complicated, time-consuming, and very expensive. In order to obtain more effective information, reflection The scattering imaging device acquires downhole image information in batches, so as to further analyze the structural composition of downhole formations.

In the X-ray backscatter imaging logging device of the prior art, the source collimator of the X-ray generating device adopts a fixed and unidirectional emission structure, which emits continuous X-rays along the periphery of the well wall through the rotation of the motor, and physically reacts with the well wall . First of all, due to the limitation that traditional flat-panel detectors cannot be bent and folded, one detector cannot be made into a cylindrical shape to detect around the well wall. Generally, multiple flat-panel detectors are spliced into a cylindrical detector array in a certain way, and each detector is used later. The collected information is calculated to obtain the relevant image. Therefore, the direction of the source collimator in the current X-ray backscatter imaging logging device cannot be adjusted, and thus the optimal angle between the collimator, the borehole wall and the detector cannot be automatically adjusted, which limits the application of different downhole environments. image quality. Secondly, there are obvious creases at the junction of traditional flat-panel detectors during the splicing process, which leads to more serious scattering at the splicing point, which is not conducive to 3D X-ray imaging of curved surfaces or irregular objects. In addition, the X-ray detectors in today's well logging devices are manufactured on glass substrates, which make the overall mass large, easy to break, and difficult to transport, which restricts accurate measurement of small-caliber downhole environments.

Contents of the invention

The purpose of the present invention is to provide a logging device based on multi-dimensional imaging of flexible detectors to solve technical problems such as limited detection range, complex structure, and object imaging distortion of traditional logging devices.

To achieve the above object, the present invention adopts the following technical solutions:

A logging device based on multi-dimensional imaging of a flexible detector, including a casing, which is sequentially connected to a main control board, a motor, an X-ray generator unit, a transformer, a flexible X-ray detector, a photoelectric conversion circuit, and a data storage unit in the casing The unit and the voltage regulator; the end of the housing at one end of the voltage regulator is connected with a lower plug, and the voltage stabilizer passes through the housing to connect with the lower plug; the end of the housing at the end of the main control board is provided with an instrument Gua Bi;

The X-ray generator unit includes an X-ray emission source spectrum and n collimator devices equidistant from the X-ray emission source spectrum, and there are n control collimator devices on or off in the X-ray emission source spectrum The valve, the valve and the collimator are connected in one-to-one correspondence;

The X-ray flexible detector includes a ring-shaped flexible substrate and a detector crystal array arranged on the flexible substrate. The detector crystal array is formed by a plurality of detector crystals arranged closely in sequence; To isolate the flexible detector from the shielding cover of the X-ray source, a gap is provided between the inner wall of the shielding cover of the X-ray source and the X-ray flexible detector.

Further, the above-mentioned logging device based on flexible detector multi-dimensional imaging is also connected with an image processing and reconstruction unit, and the image processing and reconstruction unit is connected with a data storage unit; the detected well is deduced according to the energy distribution information provided by the data storage unit. The wall formation density and element content are converted into digital images to form borehole wall imaging information for well logging analysis.

Further, the collimator is an adjustable collimator, which is composed of a large ball, a small ball and a columnar collimation rod; the large ball is sleeved on the outer wall of the small ball and rotates around the small ball, and The small ball is sealed; the small ball is provided with a first opening and a second opening, and the second opening is arranged on the opposite surface of the first opening and communicates with the first opening, so as to form a passage for outgoing particles during the rotation of the large ball; One end of the straight rod is inserted into the first opening and matches the diameter of the first opening, and the other end is inserted into the spectrum of the X-ray emission source.

Furthermore, the first opening is a circular opening, and the second opening is a 150° square opening, and the continuous X-ray angle can be adjusted along the direction of the second opening by setting two openings of different shapes.

Further, the flexible substrate is made of polyvinyl alcohol (PVA), polyester (PET), polyimide (PI) or polyethylene naphthalate (PEN), and the detector crystal is selected from CsPbBr3 , Cs2TeI6, Ni-DABDT or PbI2.

Further, the size of the detector crystal array is 480×1640; each detector is square, and its pixel size is 100×100 μm ² _.

Further, while ensuring the detection effect, the overall size of the flexible detector is reduced to the minimum, and the cost is lower. In the process of the detector crystal array, the spatial position of a single detector crystal should comply with:

Vector _x,y,z ＝((R ₁ +0.5*cryst _dz )*cos(dphi _i,j ),(R ₁ +0.5*cryst _dz )*sin(dphi _i,j ),i*cryst _dx )

Among them, Vector _{x, y, z} represent the spatial position of a single detector crystal, R ₁ represents the inner diameter of the flexible detector, crystal _dx , crystal _dy , crystal _dz represent the length, width and height of a single detector crystal respectively, dphi _i,j Represents the rotation angle of a single crystal, and i, j represent the detector crystals in row i and column j.

Further, the shielding cover is made of a beryllium window, and the use of the beryllium window can effectively reduce the energy of the X-ray backscatter from the source directly to the detector.

Further, the value range of n is 4≤n≤12.

After adopting the above technical scheme, the present invention has the following beneficial effects:

1. Replace the flat-panel detector with a bendable X-ray flexible detector, reduce the area occupied by the detector, and improve the X-ray energy acquisition for irregular objects with radians.

2. In the X-ray generator unit, there are n valves for controlling the opening or closing of the collimator in the X-ray emission source spectrum. The valves are connected to the collimator in one-to-one correspondence. The open range of straightener.

3. The collimator of the X-ray generator unit is an adjustable collimator. Using this unique collimator structure can not only realize the circular detection of the instrument around the downhole, but also control the emission angle by rotating left and right. It is compatible with the detector array "Focus" the best angle of backscattering to achieve better imaging effect.

Description of drawings

Fig. 1 is the design drawing of the rotatable collimation device of X-ray backscattering instrument: (a) is the assembly drawing of multi-directional X-ray collimation device, (b), (c) are different angles rotatable schematic diagrams;

Fig. 2 is a schematic diagram of modeling a nanoscale annular flexible X-ray detector array;

Fig. 3 is a structural schematic diagram of the flexible detector imaging logging device of the present invention;

Fig. 4 is embodiment terminal host computer image processing and data analysis interface diagram;

Fig. 5 is a schematic diagram of the downhole transmission device of the X-ray backscattering flexible detector of the embodiment;

Fig. 6 is a flow chart of the X-ray backscatter imaging device of the embodiment;

Fig. 7 is the imaging result diagram of the flexible detector simulating the downhole object of the embodiment;

Fig. 8 is a comparison chart of detection efficiencies of different flexible crystal materials.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Fig. 3 is a structural schematic diagram of the flexible detector imaging logging device of the present invention. As shown in Fig. 3, a logging device based on flexible detector multi-dimensional imaging provided by this embodiment includes a casing in which a main control board, a motor, an X-ray generator unit, a transformer, an X-ray A flexible detector, a photoelectric conversion circuit, a data storage unit, and a voltage stabilizer; the end of the housing at one end of the voltage stabilizer is connected to a lower plug, and the voltage stabilizer passes through the housing to connect with the lower plug; the housing is located at One end of the main control board is provided with an instrument wall.

Fig. 1 is a design diagram of a rotatable collimation device of an X-ray backscattering instrument: (a) is an assembly diagram of a multi-directional X-ray collimation device, and (b) and (c) are schematic diagrams of rotation at different angles. As shown in Figure 1, the X-ray generator unit includes the X-ray emission source spectrum and 6 collimator devices arranged on the X-ray emission source spectrum with equidistant rings, and 6 control collimator devices are arranged in the X-ray emission source spectrum. The valve for opening or closing the collimator, 6 valves and 6 collimators are connected one by one. The collimator is an adjustable collimator, which consists of a large ball, a small ball and a columnar collimation rod; the large ball is set on the outer wall of the small ball, and rotates on the small ball as the axis, and rotates the dynamic sealing ball; The small ball is provided with a first opening and a second opening, and the second opening is arranged on the opposite surface of the first opening and communicates with the first opening to form a passage for the outgoing particles during the rotation of the large ball; one end of the columnar collimation rod is inserted into the The first opening is matched with the diameter of the first opening, and the other end is inserted into the spectrum of the X-ray emission source. The two openings on the ball have different shapes. The first opening is a circular opening, and the second opening is a 150° square opening. An external collimation servo is used to control the rotation angle in the left and right directions.

The collimator device of this embodiment solves the drawbacks of conventional collimator devices with a single emission direction. When in use, the instrument can be rotated around the downhole ring to detect while the instrument can also be rotated left and right to control the emission angle. The array "focuses" on the backscatter optimal angle. During implementation, the working states of the n collimators on the spectrum of the surrounding device and the X-ray emission source are controlled through the valves connected thereto. Usually, the more collimators in a single cycle, the finer the imaging information can be collected, and more 2D pictures can be obtained, which is helpful for later 3D reconstruction. Affected by construction technology and cost, the number of collimators should be controlled to be greater than or equal to 4 and less than or equal to 12, preferably 6 in this embodiment.

Fig. 2 is a schematic diagram of modeling a nanoscale annular flexible X-ray detector array. As shown in FIG. 2 , the X-ray flexible detector includes a ring-shaped flexible substrate and a detector crystal array arranged on the flexible substrate. The size of the detector crystal array is 480×1640. It is composed of a plurality of detector crystals arranged closely one by one, each detector is square, and its pixel size is 100×100 μm ² . The flexible substrate is selected from polyvinyl alcohol (PVA), polyester (PET), polyimide (PI) or polyethylene naphthalate (PEN), and the detector crystal is selected from CsPbBr3, Cs2TeI6, Ni -DABDT or PbI2 will work. In this embodiment, polyester (PET, C10H8O4 1.38g/cm3) or polyimide (PIs, C35H28N2O7 1.47g/cm3) is used as the substrate. The organic material is used to achieve angular bending to make it into a ring, so that it can correspond to the collimator in the axial direction. The detector crystal is CsPbBr3, which can be sprayed on the substrate through a chemical process during manufacture. In the embodiment, in order to make the X-ray flexible detector the smallest size, the lowest cost, and have the best detection effect, it is necessary to make requirements on the spatial position of a single detector crystal. specific:

The overall size of the X-ray flexible detector is related to the relative arrangement position of a single detector crystal array, the bending angle of the detector, and the size of a single crystal. Let the three-dimensional dimensions of a single crystal be dx, dy, dz respectively, and the size of the detector matrix be m×n. When the bending angle of the flexible detector is θ, in order to achieve a close arrangement, each corresponding pixel needs to be rotated by an angle of dphi _{i ,j} ,:

dphi _i,j = θ _start +j*θ/n (1)

Since the crystal has a certain thickness, the inner diameter and outer diameter corresponding to the curved surface of the detector are R ₁ and R ₂ . Through calculation, the corresponding inner and outer radii of the curved surface can be obtained according to the bending angle and the size of the crystal:

Since the arrays are arranged in sequence, the spatial position of a single crystal in a complete detector array can be expressed by formula (4):

Vector _x,y,z ＝((R ₁ +0.5*cryst _dz )*cos(dphi _i,j ),(R ₁ +0.5*cryst _dz )*sin(dphi _i,j ),i*cryst _dx ) ( 4)

In this embodiment, a shielding cover is placed outside the X-ray flexible detector to separate the detector from the X-ray source, and by isolating the X-ray source and the flexible detector, the X-ray backscattering source can be effectively reduced from directly reaching the detector. energy of. The logging device based on the multi-dimensional imaging of the flexible detector is also connected with an image processing and reconstruction unit, and the image processing and reconstruction unit is connected with the data storage unit; according to the energy distribution information provided by the data storage, the formation density and element content of the detected borehole wall are deduced , and then convert it into a digital image to form borehole wall imaging information for well logging analysis. The image processing and reconstruction unit in this embodiment is completed by the host computer terminal. Fig. 4 is an interface diagram of image processing and data analysis of the host computer terminal in this embodiment. As shown in Figure 4, the information provided by the data storage unit is sliced through a series of pictures on the host computer terminal, and finally the image reconstruction of the complete well wall is realized through the reconstruction algorithm.

Fig. 6 shows the detailed process of logging with the upper device logging device, as shown in Fig. 6, including the following steps:

Step 1. As shown in FIG. 5 , use cables to fix the wall of the instrument, place the logging device of this embodiment downhole, and transport it to the designated detection area through the transmission device.

Step 2. Turn on the X-ray emission source spectrum after the well logging device of this embodiment is transported to the relevant area, and the X-ray X-ray emission source spectrum generates continuous X-rays. The X-rays irradiate the formation after passing through the collimator tube. During the irradiation process, the logging device of this embodiment is placed to rotate 360 degrees along with the cable and rise continuously to ensure all-round irradiation of the formation. Set the angular velocity of the motor to ω (rad/s), the velocity in the vertical direction to v _z (m/s), select the number of collimators as n, scan one cycle time around the downhole as t=2π/ωn, and the length of the ring detector is H, v _z = H/t = H/(2π/ωn) in the same time, and then obtain the vertical direction velocity v _z and motor angular velocity ω, the number of collimators is 6, and each collimator is equipped with one The relationship between the source collimation steering gear used to control its left and right rotation angle and the length of the ring detector is v _z =Hωn/2π.

Step 3. After being absorbed and scattered by the formation and well fluid, the irradiated X-rays are detected by the annular flexible detector array. The low-energy X-rays emitted by the source react with the formation to produce characteristic X-rays, and then are received by the CsPbBr3 flexible detector. , the detected relevant information is transmitted to the data storage unit, and at the same time, the data of the data storage unit is continuously transmitted to the host computer terminal through the data line.

Step 4. The upper computer terminal combines the two-dimensional image information provided by the data storage unit to realize three-dimensional reconstruction, and forms complete wellbore imaging information.

In order to verify the advantages of the bendable flexible detector in the above-mentioned logging device compared with the flat-panel detector for imaging irregular curved surface geometry. Fig. 7 is a diagram showing the imaging result of a simulated downhole object by the flexible detector of the embodiment. As shown in FIG. 7 , this embodiment simulates a semi-circular geometry with five defects at different positions, which are respectively imaged with a traditional flat panel detector and a bendable flexible detector. Compared with the incomplete imaging of defects by the flat panel detector, that is, the flat panel detector presents three defects, and the edge distortion and scattering are more serious, the flexible detector used in the logging device of this embodiment can completely image the shape and position of the five defects , while the influence of imaging distortion and distortion is improved. This shows that this embodiment is optimized for the imaging of downhole irregular objects.

Fig. 8 is a comparison chart of detection efficiencies of different flexible crystal materials. As shown in Figure 8, by comparing the detection efficiency of the flexible detector crystal (CsPbBr3, Cs2TeI6) used in this embodiment and the traditional detector crystal (NaI, CsI), the detector crystal CsPbBr3 used in this logging device is 10mm The detection efficiency reaches 95% under the crystal thickness, and the NaI detector used in the existing logging device has a detection efficiency of 80% under the same thickness, so the logging device of this embodiment effectively improves the detection and energy acquisition of X-rays .

It is not difficult to see from the above embodiments that the logging device provided by the present invention is based on the limitations of the current downhole imaging device, mainly improving the X-ray collimator and detector, and improving the automatic image processing platform based on the existing logging device . By designing an X-ray collimator device adjustable in multiple directions, the X-ray coverage area can be increased, and at the same time, it can adapt to the best irradiation angle for different downhole environments. By transforming the traditional flat-panel detector into an angle-bendable flexible detector, the problem of severe scattering between flat-panel detectors and poor imaging effect is solved. In addition, flexible crystal materials based on nano-scale crystal materials have the advantages of small particle size, easy preparation and good combination of various materials, which provide a great opportunity for large-scale, flexible, and ultra-sensitive X-ray detectors. Large-scale production and application Feasibility is provided.

Claims (9)

1. A logging device based on flexible detector multi-dimensional imaging comprises a shell, a main control board, a motor, an X-ray generator unit, a transformer, an X-ray flexible detector, a photoelectric conversion circuit, a data storage unit and a voltage stabilizer, wherein the main control board, the motor, the X-ray generator unit, the transformer, the X-ray flexible detector, the photoelectric conversion circuit, the data storage unit and the voltage stabilizer are sequentially connected in the shell; the end part of the shell, which is positioned at one end of the voltage stabilizer, is connected with a lower plug, and the voltage stabilizer penetrates through the shell to be connected with the lower plug; an instrument wall is arranged at the end part of the shell positioned at one end of the main control board; the method is characterized in that:

the X-ray generator unit comprises an X-ray emission source spectrum and n collimator devices annularly arranged on the X-ray emission source spectrum at equal intervals, wherein n valves for controlling the collimators to be opened or closed are arranged in the X-ray emission source spectrum, and the valves are connected with the collimators in a one-to-one correspondence manner;

the X-ray flexible detector comprises an annular flexible substrate and a detector crystal array arranged on the flexible substrate, wherein the detector crystal array is formed by sequentially and tightly arranging a plurality of detector crystals; a shielding cover used for isolating the flexible detector from the X-ray source is sleeved outside the X-ray flexible detector, and a gap is formed between the inner wall of the shielding cover of the X-ray source and the X-ray flexible detector.

2. The logging device based on flexible detector multi-dimensional imaging of claim 1, characterized in that: the flexible detector imaging logging device based on the X-ray backscatter is also connected with an image processing and reconstructing unit, and the image processing and reconstructing unit is connected with a data storage unit; deducing the formation density and element content of the detected well wall according to the energy distribution information provided by the data storage unit, and converting the information into a digital image to form well wall imaging information for well logging analysis.

3. The logging device based on flexible detector multi-dimensional imaging of claim 1, characterized in that: the collimator is an adjustable collimator and consists of a large ball, a small ball and a columnar collimating rod; the big ball is sleeved on the outer wall of the small ball, rotates by taking the small ball as an axis and rotationally seals the small ball; the small ball is provided with a first opening and a second opening, and the second opening is arranged on the opposite surface of the first opening and communicated with the first opening so as to form an emergent particle channel in the rotation process of the large ball; one end of the columnar collimation rod is inserted into the first opening and matched with the caliber of the first opening, and the other end of the columnar collimation rod is inserted into an X-ray emission source spectrum.

4. A logging device based on flexible detector multi-dimensional imaging according to claim 3, characterized in that: the first opening is a circular opening, the second opening is a square opening of 150 degrees, and continuous X-rays are adjustable in angle along the direction of the second opening through the arrangement of the two openings in different shapes.

5. The logging device based on flexible detector multi-dimensional imaging of claim 1, characterized in that: the flexible substrate is made of polyvinyl alcohol (PVA), polyester (PET), polyimide (PI) or polyethylene naphthalate (PEN), and the detector crystal is made of CsPbBr3, cs2TeI6, ni-DABDT or PbI2.

6. The logging device based on flexible detector multi-dimensional imaging of claim 1, characterized in that: the detector crystal array size is 480 × 1640; each detector is square with a pixel size of 100 x 100 μm ² 。

7. The logging device based on flexible detector multi-dimensional imaging of claim 1, characterized in that: in the array process of the detector crystal, the spatial position of the single detector crystal is in accordance with:

Vector _x,y,z ＝((R ₁ +0.5*cryst _dz )*cos(dphi _i,j ),(R ₁ +0.5*cryst _dz )*sin(dphi _i,j ),i*cryst _dx )

wherein Vector _x,y,z Representing the spatial position, R, of a single detector crystal ₁ Representing the internal diameter, crystal, of the flexible probe _dx 、cryst _dy 、cryst _dz Respectively representing the length, width, height, dphi of a single detector crystal _i,j The rotation angle of a single crystal is shown, and i, j represents the ith row and j columns of detector crystals.

8. The logging device based on flexible detector multi-dimensional imaging of claim 1, characterized in that: the shielding cover is made of beryllium windows.

9. A logging device based on flexible detector multi-dimensional imaging according to any one of claims 1 to 7, characterized in that: the value range of n is more than or equal to 4 and less than or equal to 12.

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