Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B47/00—Survey of boreholes or wells
  • E21B47/10—Locating fluid leaks, intrusions or movements
  • E21B47/11—Locating fluid leaks, intrusions or movements using tracers; using radioactivity
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B47/00—Survey of boreholes or wells
  • E21B47/12—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
  • E21B47/138—Devices entrained in the flow of well-bore fluid for transmitting data, control or actuation signals

Definitions

• the present invention relates generally to the field of subsurface monitoring and communication techniques. More specifically, the invention relates to the use of tracers or marker materials in combination with wired tubulars for subsurface measurements.
• Drilling operations in the oil and gas industry typically entail the circulation of a drilling fluid ("mud") down the drill string, through the drill bit and up along the annulus to surface.
• the drilling mud has various functions including cooling, cleaning and lubricating the drill bit and bottom-hole assembly, controlling subsurface pressures to give wellbore stability and prevent fluid influxes, and transporting drill cuttings to the surface where they can.be separated and disposed of.
• Downhole pressure control is a primary function of the drilling mud. Maintaining hydrostatic pressure to prevent fluid influxes which may lead to kicks and a well control situation is crucial. However, the circulating pressure must be controlled to be below the fracture pressure for the formation otherwise fractures can propagate causing loss of drilling fluid from the wellbore. In extreme cases this could cause loss of hydrostatic pressure in part of the annulus where a fluid influx could occur. Various techniques have been considered to monitor flow rates.
• Efficient cuttings transport is another key function of the drilling mud.
• the rheological properties of the mud are engineered to suspend and lift the cuttings in the circulating fluid.
• the conditions in the annulus particularly diameter and inclination, can affect flow rates, and lessen transport efficiency.
• cuttings beds can build up on the bottom side of the hole. This is a particular problem in high angle holes where the cuttings bed may slump down the annulus and packoff the drill string causing pipe sticking, twist offs and potentially lost circulation if a weak formation lies below the obstruction in the annulus.
• Washout zones are zones of high formation erosion which can be indicative of, or cause wellbore stability problems and can lead to further problems in efficiently cementing the well. Early detection of trouble zones and timely intervention could prevent costly operational problems.
• a conventional technique for determining lag time entails the injection of Calcium Carbide pellets, enclosed in a water-proof container, at the surface of the well being drilled for transit down the borehole by the mud stream. When passing through the drill bit, the container is smashed releasing the calcium carbide that reacts with water in the mud to form a gas, Acetylene, which is detected at the surface with a gas analyzer. The lag time can therefore be determined from the time difference between the injection of the Calcium Carbide in the well and the detection of gas at the surface in the return mud.
• the addition of rice to the mud stream has also been used as a tracking technique to determine lag time.
• U.S. Patent No. 4,447,340 describes a method of tracing drilling mud by determining the concentration of Acetate tracer ion in the penetrated strata (by core analysis).
• the use as tracers of Dichromate, Chromate, Nitrate, Ammonium, Cobalt, Nickel, Manganese, Vanadium and Lithium is also mentioned.
• Some tracer techniques have also been proposed using spectroscopic techniques, including atomic absorption spectroscopy, X-ray fluorescence spectroscopy, or neutron activation analysis, to identify certain materials as tagging agents.
• 6,725,926 proposes the use of a proppant coated with phosphorescent, fluorescent, or photo luminescent pigments that glow in the dark upon exposure to certain lighting. Fluorescence spectrometry techniques entailing the illumination of fluids with a light source have also been proposed (See U.S. Patent Nos. 7,084,392, 6,707,556, 6,564,866, 6,955,217). [0008] A need remains for improved techniques to determine dynamic subsurface conditions, particularly in the field of oil, gas, or water exploration and production.
• One aspect of the invention relates to a downhole system that includes at least one tag configured to provide a distinguishable identifier and set for selective release to a subsurface location and at least one sensor disposed in the borehole to detect the at least one tag at a subsurface location.
• the at least one sensor may be configured to transmit a signal associated with the at least one detected tag a surface.
• Another aspect of the invention relates to a method that includes detecting at least one tag at a subsurface location with a sensor disposed in the borehole, the tag configured to provide a distinguishable identifier and conveying a signal associated with the at least one detected tag to a surface location.
• Another aspect of the invention relates to a downhole method that includes activating at least one source or sensor disposed in the borehole to detect a tag at a subsurface location, the tag configured to provide a distinguishable identifier and conveying a signal associated with the detected tag along an interconnected wired tubular.
• FIG. 1 is a schematic of an example downhole system including tag release units and a tag detection unit.
• FIG. 2 is a schematic of an example tag release unit.
• FIG. 3 is a schematic of an example downhole system including tag activation/detection units.
• FIG. 4 is a flow chart of an example downhole method for detecting one or more tags.
• FIG. 5 is a flow chart of an example downhole method for activating one or more tags.
• Disclosed examples entail the use of wired tubulars configured for downhole applications. Such tubulars are configured with one or more conductors running through the bore, or disposed within/against/outside the wall, of the tubular. Couplers mounted on the ends of the tubulars allow for conveyance of a signal/power along a string of interconnected tubulars.
• Wired drill pipe is one such type of tubular.
• Conventional wired drill pipe configurations that may be used to implement aspects of the invention are described in U.S. Patent Nos. 7,168,510, 6,950,034, 6,641,434, 6,866,306, 7,040,415, 7,096,961, U.S. Patent Publication Nos. 20070063865, 20070159351, 20070188344, and 20060225926 (all documents incorporated herein by reference in their entirety).
• FIG. 1 shows an aspect of the invention.
• a system 11 includes a drill string 20 comprising a plurality of interconnected wired drill pipes 21, shown disposed within a borehole 22 traversing a subsurface formation F as the hole is cut by the action of the drill bit 24 mounted at the far end of a bottom-hole assembly (BHA) 26.
• BHA 26 contains a number of devices including various subassemblies 28, including those used for measurement-while-drilling (MWD) and/or logging-while-drilling (LWD). Signal data between the subassemblies 28 and the surface is communicated via the interconnected wired drill pipes 21 as known in the art.
• MWD measurement-while-drilling
• LWD logging-while-drilling
• the signal data may be conveyed via a series of wired drill pipes 21 in combination with another telemetry assembly (e.g., via pressure pulses through the drilling mud, via a wireline cable in the drill string) (not shown) as known in the art.
• another telemetry assembly e.g., via pressure pulses through the drilling mud, via a wireline cable in the drill string
• the system 11 includes a derrick 30 and hoisting system, a rotating system, and a mud circulation system.
• a mud circulation system pumps drilling fluid down the central opening in the drill string 20.
• the mud is stored in a mud pit which is part of a mud separation and storing system 32.
• the mud is drawn in to mud pumps (not shown) which pump the mud through stand pipe 34 and into the Kelly and through the swivel.
• the mud passes through drill string 20 and through drill bit 24.
• the mud is ejected out of openings or nozzles in the bit. These jets of mud lift the cuttings off the bottom of the hole and away from the bit, and up towards the surface in the annular space between drill string 20 and the wall of the borehole 22, as represented by arrows in FIG. 1.
• the mud return line 38 feeds the mud into the separation and storing system 32, which separates the mud from the cuttings. From the separator, the mud is returned to a mud pit (not shown) for storage and re-use.
• tags 10 are understood to comprise any conventional tracer/marker element or composition configured to provide a distinguishable identifier as known in the art.
• tags 10 are generally miniature in size and configured in various shapes and dimensions (e.g., a ball, bead, rod, ribbon, sphere, globule, droplet, tube).
• the term "subsurface” is herein understood as, relating to, or situated in an area beneath a surface, especially the surface of the earth or of a body of water.
• a subsurface component is understood to comprise a buried, submerged, or partially buried/submerged component.
• tags 10 are disposed in the mud separation and storing system 32, such that they are set for selective release to a subsurface location via the mud flow.
• a tag 10 detection unit 40 is shown coupled into the mud return line 38 and linked to surface equipment 42 comprising computer, display, recording, and user interface means as known in the art.
• the detection unit 40 includes appropriate components to activate/detect the passing tags 10 in order to resolvable/identify the individual tags.
• a radiation source e.g., UV lamp
• optics to provide appropriate wavelength illumination may be included in the detection unit 40.
• the detection unit 40 is incorporated with a filtering or separating device, such as a centrifuge, to collect the tags 10 for analysis.
• the detection unit 40 can be implemented with magnetic means (e.g., permanent magnet or electromagnet) to collect the particles for processing (not shown).
• a system can be implemented wherein the tags 10 are set in a release mechanism disposed on the BHA 26, or anywhere along the drill string 20, such that they are selectively or automatically released subsurface at a desired depth or when a predetermined event occurs, or at specified times. Tagging of solids and fluids downhole gives a more precise to time event for both.
• FIG. 1 illustrates such an aspect of the invention.
• the BHA 26 may be implemented with a tool comprising a tag 10 release unit 44.
• a tag release unit 44 may be implemented with a sensor 46 adapted to sense a subsurface characteristic or condition (e.g., pressure, temperature, fluid composition, flow rates, etc.). Sensors of these types are well known technology, as are the means to power the sensors. Sensor 46 is in communication with a processor 48 which may comprise a number of microprocessors.
• a processor 48 which may comprise a number of microprocessors.
• One or more chambers 50, 52 contain the tags 10. Aspects can be implemented with different types of tags 10 (e.g., various sizes, activation modes, liquid type, solid type, etc.) disposed in each chamber 50, 52 for selective release of the desired tag(s) at the desired times.
• release mechanisms 54, 56 Associated with the chambers 50, 52 are release mechanisms 54, 56. Under control of processor 48, the release mechanisms 54, 56 can be activated to selectively release the respective tag(s) 10.
• the release mechanisms 54, 56 may be configured to release the tag(s) 10 via a forced or pressurized ejection (e.g., pneumatic, hydraulic, electronic, mechanical means), via direct exposure of the tags to the mud flow, or some combination of these methods as known in the art.
• the release mechanisms 54, 56 may be instructed to release the tags 10 in accordance with a program in the processor 48.
• the release mechanisms 54, 56 can be instructed to selectively release their tags 10 when different predetermined thresholds or conditions are determined by the sensor 46, based on input from other sensors in the system, or via direct control from a surface operator/computer with signaling conveyed along the wired drill pipes 21.
• the use of interconnected wired tubulars in aspects of the invention allows for real-time signal/data transfer and correlation to depth/rime of subsurface tag 10 release and/or detection.
• the wired drill pipes 21 are also equipped with conventional sources/sensors 60 configured to activate and/or detect tags 10 in their vicinity as known in the art and disclosed herein.
• U.S. Patent Publication No. 20060260801 to Hall describes wired drill pipes equipped with sensors and power sources to obtain subsurface measurements.
• U.S. Patent No. 6,577,244 (assigned to the present assignee and entirely incorporated herein by reference) describes a drill pipe system providing various types of sources/sensors for subsurface measurements. As discussed above, aspects of the invention may be configured with "hybrid" telemetry systems incorporating the wired drill pipes 21 in combination with drill pipe systems such as described in U.S. Patent No. 6,577,244.
• FIG. 3 shows another example of a tagging system.
• a system 70 is shown disposed within a cased well 51.
• the well 51 is configured with conventional tubing/liners/casmg 53 as known in the art.
• a drill string 20 comprising a plurality of interconnected wired drill pipes 21 is disposed within the well 51.
• the wired drill pipes 21 are equipped with conventional sources/sensors 60 configured to activate and/or detect tags 10 in their vicinity as known in the art.
• one can perform status/performance checks such as identifying the position of cement 57 behind casing by detection of tags 10 that have been added to the cement.
• the system 70 may also be used to provide positive communication to the surface regarding a specific subsurface condition, such as confirmation that gravel packing (incorporating tags 10) was properly placed or distributed in the well (not shown). Such functions can be performed while tripping the drill string 20 in or out of the well 51. As with the other aspects of the invention, this system may also be configured for selective release of the particles 10 from the surface and/or the BHA as disclosed herein.
• example systems may be implemented with tags 10 comprising any conventional tracer/marker material or composition configured to provide a distinguishable identifier as known in the art.
• aspects of the invention can be configured to detect tags 10 exhibiting fluorescence emission.
• Instruments configured to detect fluorescence emission downhole are known in the art.
• U.S. Patent No. 6,704,109 (incorporated herein by reference in its entirety) describes a tool equipped with a probe system to illuminate crude oil in the well and detect the emitted fluorescence. Examples may be implemented with similar optical systems such that the tags 10 can be released, irradiated, and observed subsurface.
• one or more drill pipes 21 may be equipped with a source/sensor 60 comprising a fluorescence detector unit configured to illuminate and detect tags 10 previously released or affixed to the borehole/casing wall, such as tags disposed in proppant/fracturing compounds and stuck in fissures or mudcake.
• the distribution of sources/sensors 60 along the drill string 20 permits spatial resolution to obtain measurements and track fluid/cuttings flow while drilling.
• the surface equipment 42 alone or in combination with processors in the downhole tool(s), can be programmed to automatically alter operation of surface and subsurface components based on the tag-related measurements obtained subsurface and/or at surface.
• Such a feedback/control loop can be configured to affect operations to alter pump rates, torque, ROP, pipe rotation, tripping rates, activate/deactivate instruments, etc. For example, on detection of a cuttings bed a command could be sent to increase rotation rate and activate the sensors to monitor the cuttings bed pickup. Such controls can be maintained to correct or stabilize downhole conditions.
• tags 10 can be activated/released to tag the drilling mud and cuttings at the BHA 26. These tags 10 travel up the annulus and experience hydro dynamical dispersion and convectional and diffusional mixing effects. On detection of the tags 10 at the sensors 60 along the wellbore and/or at surface 40, the difference in time of flight can be calculated. Where the two deviated significantly, a zone of cuttings holdup can be identified.
• the tag(s) 10 can be automatically or manually released into the annulus from the surface, at the bit 24, or near the bit at the BHA 26, with data transmitted near instantly along the wired drill pipe 21 system.
• measurement of dispersion and transit of the drilling mud can be done through soluble ions, as described in U.S. Patent No. 4,807,469 (assigned to the present assignee and entirely incorporated herein by reference).
• Sensors 60 comprising conductivity or ion-specific sensors on the drill string 20 are used to detect the passage of ions.
• tags 10 comprising dyes which are detectable at specific wavelengths or fluorescence used in conjunction with sensors 60 comprising optical sensors.
• Tags 10 exhibiting other spikes in chemical composition such as pH may also be used provided that the other properties of the fluid remain unaffected. Solid transit could be done hy dosing the mud with a tag 10 comprising a weighting agent (e.g., NORM Barite or other detectable solids added at the surface or the BHA). Brazil nut shells, for example, provide significant natural radiation and are available as loss prevention materials.
• a weighting agent e.g., NORM Barite or other detectable solids added at the surface or the BHA.
• Electronic tags 10 such as encapsulated radio-frequency identification (RFID) tags may also be used.
• RFID tags are configured for activation/interrogation by EM energy and have been proposed for use in subsurface applications.
• U.S. Patent No. 6,993,432 (incorporated herein by reference in its entirety) describes the use of RFID tags for communication means in a wellbore. Examples may be implemented with conventional EM sources/sensors 60 (e.g., as described in U.S. Patent No. 6,577,244) configured to detect/interrogate such tags 10 subsurface.
• the tags 10 can be used in a circulating sweep. Pills of more viscous fluid are often deployed to displace cutting which have become help-up. The arrival of the sweep and its effectiveness could be monitored.
• the feedback/control loop of the disclosed systems can be used to alter components and parameters timed to the arrival of the sweep.
• Processing of detected tags 10 can be carried out using conventional techniques. For example, upon identification of a tag 10, the distinguishable tag identifier can be matched against a reference database or "code chart.” It will be appreciated by those skilled in the art that any suitable tags 10 and corresponding sources/sensors 46 may be used to implement embodiments of the invention.
• the detection and identification of the tags 10 can be assisted by the use of a camera that can be used to record images or display on a screen.
• An aspect of the detection unit 40 of FIG. 1 may comprise a conventional camera configured to record and display images on a screen.
• the surface equipment 42 may also be configured with a program to identify the tags, establish tag identifier matching, process the resolved/identified tag data, track tag travel times, automatically trigger selected tag release, and respectively transmit/receive data/commands to/from remote locations.
• the surface equipment 42 may be configured with programming to perform image analysis for tag identification.
• a simplistic system can be implemented wherein the tags 10 are initially disposed in the mud manually and captured in the return line 38 (e.g., using a screening filter, magnet means, centrifuge or separator) for processing by rig personnel.
• Mud logging - The use of uniquely identifiable tags added to the drilling mud at different times provides different types of information:
• the travel time of different tags can be logged.
• the time between the release and the detection of the tags can be measured, as well as the travel time between two or more established locations.
• Timed tag release allows for direct cuttings transport rate measurements for hole-cleaning calculations, deduction of hole volume/gauge via annular velocity measurement with a known flow rate, identification of "thief zones" at times of lost circulation/signal.
• Mud cake tagging The use of uniquely identifiable tags added to the drilling mud at different times can tag the mud cake as a function of depth that is correlated with the drilling depth. This provides for:
• the amount and type of debris may be estimated using the tags.
• a tag release unit can selectively release a combination of tags into the mud to convey information from the drill bit to surface.
• Gravel pack monitoring Different types of tags can be added to the g ⁇ avel at different times during the gravel packing operation. The effectiveness of the placement at different stages of the operation can be monitored by analyzing the concentration of the different tags detected by the passing wired tubulars. This can be used to identify which region of a gravel pack has failed, for example.
• tags into the mud flow can be used to obtain flow velocity.
• the tags' surface can be treated as known in the art to increase their affinity to a given fluid when multi-phase flows are measured. Monitoring of circulated "pills” and “sweeps” or other wellbore treatments.
• Tags can be sent from the surface or selectively released subsurface to test the operation of downhole instruments or to determine/monitor downhole conditions.
• Tags can be added to the mud, cement, acid, injection fluid, produced fluid, fracturing fluid, proppant, treatment fluid, gravel, etc.
• the location of an event can be determined by the type and concentration of tags detected.
• Different tag sizes can be used in combination to perform any of the operations disclosed herein. For example, the use of different sized tags allows for determination of the size of a fracture, fault, porous medium, etc., that serves as a conduit to the fluids or tags.
• the tags can also be mixed with solid acids or other compounds to track/monitor completion operations.
• FlG. 4 shows a flow chart of an example downhole method 100 that includes, at step 105 disposing a plurality of interconnected wired tubulars 21 within a borehole traversing a subsurface formation.
• at step 110 at least one tag 10 is detected at a subsurface location with a sensor 60 disposed in the borehole.
• the tag 10 may be configured to provide a distinguishable identifier via any conventional means as known in the art and disclosed herein.
• a signal associated with the at least one detected tag 10 is conveyed along an interconnected wired tubular 21.
• the signal may be conveyed solely along the wired tubulars 21 or in combination with other telemetry assemblies as known in the art and disclosed herein.
• FIG. 5 shows a flow chart of another example downhole method 200 that includes, at step 205, disposing a plurality of interconnected wired tubulars 21 within a borehole traversing a subsurface formation.
• at step 210 at least one source/sensor 60 disposed in the borehole is activated to detect a tag 10 at a subsurface location.
• the source/sensor 60 may comprise any conventional sources or sensors as known in the art and disclosed herein.
• the tag 10 may be configured to provide a distinguishable identifier via any conventional means as known in the art and disclosed herein.
• a signal associated with the at least one detected tag 10 is conveyed along an interconnected wired tubular 21.
• the signal may be conveyed solely along the wired tubulars 21 or in combination with other telemetry assemblies as known in the art and disclosed herein.
• aspects of the invention may be implemented using one or more suitable general-purpose computers having appropriate hardware and programmed to perform the techniques disclosed herein.
• the programming may be accomplished through the use of one or more program storage devices readable by the computer processor and encoding one or more programs of instructions executable by the computer for performing the operations described above.
• the program storage device may take the form of, e.g., one or more floppy disks; a CD ROM or other optical disk; a magnetic tape; a read-only memory chip (ROM); and other forms of the kind well known in the art or subsequently developed.
• the program of instructions may be "object code,” i.e., in binary form that is executable more-or-less directly by the computer; in "source code” that requires compilation or interpretation before execution; or in some intermediate form such as partially compiled code.
• object code i.e., in binary form that is executable more-or-less directly by the computer
• source code that requires compilation or interpretation before execution
• some intermediate form such as partially compiled code.
• processing means may be implemented in the surface equipment, in the system tools, in a location remote from the well site (not shown), or shared by these means as known in the art.
• aspects of the invention may also be implemented using conventional display means situated as desired to display processed or raw data/images as known in the art.
• the above disclosed examples include interconnected wired tubulars, or wired drill pipe, as a telemetry method. This is only provided as an example.

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• Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Physics & Mathematics (AREA)
• Geology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Fluid Mechanics (AREA)
• Environmental & Geological Engineering (AREA)
• Geophysics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
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• Geophysics And Detection Of Objects (AREA)
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• 2007
  • 2007-12-13 US US11/955,518 patent/US20090151939A1/en not_active Abandoned
• 2008
  • 2008-12-09 BR BRPI0819918A patent/BRPI0819918A2/pt not_active Application Discontinuation
  • 2008-12-09 WO PCT/IB2008/003938 patent/WO2009090494A2/en not_active Ceased
  • 2008-12-09 GB GB201011003A patent/GB2469233C2/en active Active
• 2009
  • 2009-10-08 US US12/575,866 patent/US20100044034A1/en not_active Abandoned

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