WO2015195552A1 - Procédé pour évaluer des vides dans une formation souterraine - Google Patents

Procédé pour évaluer des vides dans une formation souterraine Download PDF

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Publication number
WO2015195552A1
WO2015195552A1 PCT/US2015/035821 US2015035821W WO2015195552A1 WO 2015195552 A1 WO2015195552 A1 WO 2015195552A1 US 2015035821 W US2015035821 W US 2015035821W WO 2015195552 A1 WO2015195552 A1 WO 2015195552A1
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WO
WIPO (PCT)
Prior art keywords
radiation
wellbore
formation
void
source
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PCT/US2015/035821
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English (en)
Inventor
John Edward SMAARDYK
Donald K. Steinman
Russel HERTZOG Jr.
Original Assignee
Ge Oil & Gas Logging Services, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US14/305,677 external-priority patent/US20140291500A1/en
Application filed by Ge Oil & Gas Logging Services, Inc. filed Critical Ge Oil & Gas Logging Services, Inc.
Publication of WO2015195552A1 publication Critical patent/WO2015195552A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V5/00—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity
    • G01V5/04—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging
    • G01V5/08—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays
    • G01V5/12—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using gamma or X-ray sources
    • G01V5/125—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using gamma or X-ray sources and detecting the secondary gamma- or X-rays in different places along the bore hole

Definitions

  • the invention relates generally to assessing fractures in a subterranean wellbore. More specifically, the present invention relates to a device and method that uses a radiation source in conjunction with a radiation detector for a time lapsed evaluation of fractures in a formation intersected by the wellbore.
  • Subterranean wellbores used for producing hydrocarbons typically are lined with a casing string that is cemented to the formation intersected by the wellbore.
  • the casing and the surrounding formation are then perforated to provide fluid communication between the formation and interior of the casing. Fluid produced from the well flows through the perforations, to within the casing, and to the surface within production tubing that is inserted inside the inner casing string.
  • Some hydrocarbon bearing formations can have low permeability due to the presence of shale, or very tight formation rock (such as in limestone formations); which in turn can limit hydrocarbon production.
  • natural or man-made fractures in these formations can increase formation permeability thereby increasing hydrocarbon production. Identifying the location and size of these fractures are of considerable importance in determining which part of the borehole to perforate and produce.
  • a layer of shale is on top of a formation that contains hydrocarbons. Generally, it is more stable to drill in the layer of shale than the hydrocarbon bearing formation. In these situations, a wellbore is drilled through the shale with the hopes of intersecting a fracture in the shale that extends into the reservoir having the hydrocarbons, as fractures increase permeability of a subterranean formation.
  • Wellbores often include portions that are lined with a gravel pack, which is made up of particles of a designated size that are retained between a perforated tubular in the wellbore and the wellbore wall.
  • the gravel pack which is typically one or more of sand, gravel, or proppant, provides support for unconsolidated zones in the subterranean formation surrounding the wellbore. Without gravel pack, unrestrained particulate matter in the formation could become dislodged as produced fluid flows from the formation, which could possibly damage tubulars, valves, and other fluid production hardware.
  • the gravel pack is also sometimes forced into the subterranean fractures to not only prevent unwanted particulate matter in the formation from entering the produced fluid, but also to support the fractures and prevent them from collapsing.
  • a method of imaging a wellbore which includes directing radiation from a source to a formation surrounding the wellbore, detecting radiation scattered from the formation, estimating a rate and energy of the detected radiation, and estimating information about a change of a void in the formation based on the rate and energy of the detected radiation.
  • the void can be a fracture or a perforation.
  • the steps of directing radiation, detecting scattered radiation, and estimating a rate and energy can take place over time in order to perform time lapsed imaging.
  • the source can be a gamma ray source and which is directed in a substantially conical pattern from the source and wherein the energy of the detected radiation is dependent upon an angle of scatter of the radiation.
  • the information about a change of the void can be a change in thickness of the void, a change of permeability in the void, a change in flowability through the void, or a change of density of material in the void.
  • the method can optionally further include estimating a location of the void.
  • the void can be a fracture that intersects a wall of the wellbore, or a a perforation that intersects a wall of the wellbore.
  • the wellbore is an injection well, or can be a production well.
  • a method of imaging a wellbore which includes providing a logging instrument having a radiation source and a radiation detector; disposing the logging instrument into the wellbore and within casing that lines the wellbore, directing radiation from the source to a formation surrounding the wellbore and along a path, so that at least some of the radiation scatters in a direction back from the formation towards the radiation detector, detecting radiation scattered from the formation with the radiation detector, and identifying a change in a void in the formation based on a change of rate of the radiation detected.
  • the void can be an opening in the formation which is a perforation or a fracture.
  • the steps of the method are repeated over time so that the change of rate of the radiation detected comprises a time lapsed measurement.
  • the radiation can be directed fully from the outer circumference of the logging instrument so that the radiation scatters from an entire circumference of a wall of the wellbore.
  • the method can be repeated while moving the logging instrument to different depths in the wellbore.
  • An example of a method of imaging a wellbore includes directing radiation from a source to a formation surrounding the wellbore, detecting radiation scattered from the formation, estimating a rate and energy of the detected radiation, repeating the steps of directing radiation, detecting scattered radiation, and estimating a rate and energy of the detected radiation at a later time to perform a time lapsed measurement, and estimating information about a change of a void in the formation based on the time lapsed measurement.
  • Estimating information about a change of a void in the formation can be based on a rate and energy of the detected radiation.
  • a location of the void can be estimated.
  • the void can be a space in the formation such as a fracture or a perforation.
  • FIG. 1 a schematic of an example embodiment of a downhole imaging tool having a radiation source and detectors disposed in a wellbore in accordance with the present invention.
  • FIG. 2 is a perspective view of one embodiment of the tool of FIG. 1 in accordance with the present invention.
  • FIGS. 3 A and 3B are sectional views of an example embodiment of the tool of FIG. 2 in accordance with the present invention.
  • FIG. 4 is a side sectional view of an example method of an imaging tool in a wellbore that emits gamma rays to a surrounding formation in accordance with the present invention.
  • FIG. 5 is a side sectional view of an example of perforating the wellbore of FIG. 4 and in accordance with an embodiment of the present invention.
  • FIG. 6 is a side sectional view of an example method of time lapsed imaging of the wellbore with perforations of Figure 4 and in accordance with the present invention.
  • a downhole imaging tool 100 is shown positioned in a section of casing or inner steel housing 1 10 of a wellbore.
  • a tool housing 130 such as that surrounding the region of the source and detector array, may be constructed of any light metal wherein the term, "light metal,” as used herein, refers to any metal having an atomic number less than 23.
  • Downhole imaging tool 100 includes at a minimum a housing or pipe 130 carrying a radiation source 120 and plurality of detectors 140.
  • gamma radiation source 120 is centrally located in housing 130.
  • detectors 140 are symmetrically spaced apart azimuthally at a constant radius, within housing 130.
  • Radiation source 120 emits radiation, in this case, gamma rays 124 into formation 150 surrounding the casing 110.
  • Cement 151 is between the casing 1 10 and formation 150.
  • the formation 150 of Figure 1 includes fractures 153, 155 that could be fluid- filled or not.
  • fracture 153 contains completion fluids or production fluids
  • fracture 155 is partially or fully sand filled.
  • fractures 153, 155 could take any shape and any position.
  • gamma rays 124 propagating into formation 150 are Compton scattered with a loss of some energy back towards detectors 140 located within downhole imaging tool 100.
  • the reduced-energy gamma rays 126 are detected by detectors 140.
  • the count-rate intensity of Compton scattered gamma rays 126 depends on, among other factors, the size of the fracture and the density of the material inside the fracture. Hence, higher count rates represent higher density material in the formation, whereas lower count-rates represent lower density as a result of fewer gamma rays being back-scattered towards the detectors.
  • radiation source 120 includes a cesium, or some other radiation source, or combinations thereof. Because the detectors are located close to the source, energy detected from scattered gamma rays originates only from a short distance into the formation immediately adjacent the casing. For these same reasons, in one example detectors 140 are positioned in housing 130 proximate to radiation source 120. In one example embodiment, radiation source 120 and detectors 140 are within about 3 to about 3.5 inches apart along the length of tool 100.
  • Shielding 156 may be applied around radiation source 120 to collimate or otherwise limit the emission of radiation from radiation source 120 to a restricted longitudinal segment of formation 150.
  • such shielding is a heavy metal shield, such as sintered-tungsten, which collimates the pathway for the emitted gamma rays into the fractures.
  • similar shielding may be used around each detector to limit the detector viewing aperture to only those gamma rays that are primarily singly-scattered back to the detector from a restricted azimuthal section of the formation.
  • the energy levels of the emitted gamma rays 124 may be selected to assess fracture characteristics at varying depths or distances from downhole imaging tool 100.
  • the radiation from a gamma ray source such as a 133 Ba source, may be used to emit several energy levels.
  • the azimuthal angle of the logging tool relative to the high side of the borehole is determined. This orientation can be determined using any orientation device known in the art.
  • Orientation devices may contain one or more attitude sensors used to determine orientation of the logging tool with respect to a reference vector.
  • suitable orientation devices include, but are not limited to, those orientation devices produced by MicroTesla of Houston, Tex.
  • Each set of gamma ray measurements may be associated with such an orientation so that a 2D profile map of the formation can be accurately generated in terms of the actual azimuthal location of the fracture.
  • FIG. 2 illustrates a perspective view of one embodiment of a gravel pack imaging tool.
  • downhole imaging tool 200 includes a housing 230 which carries radiation source 220, source collimator 225, and a plurality of radiation detectors 240 in an array.
  • the array of detectors 240 may be positioned at a fixed distance from radiation source 220. In certain embodiments, detector arrays may be positioned at differing distances from radiation source 220. Additionally, detector arrays on either side of radiation source 220 are also envisioned in certain embodiments.
  • Electronics 260 may also be located in housing 230 or wherever convenient.
  • Radiation source 220 may be one or more radiation sources, which may include any suitable low-energy gamma ray source capable of emitting gammy ray radiation from about 250 keV to about 700 keV.
  • Gamma ray sources suitable for use with embodiments of the present invention may include any suitable radioactive isotope including, but not limited to, radioactive isotopes of barium, cesium, a LTNAC, high energy X-rays (e.g. about 200+ keV), or any combination thereof. Radiation from radiation source 220 may be continuous, intermittent, or pulsed.
  • a radiation source 220 is centrally located in housing 230.
  • source 220 is positioned along the axis of housing 230.
  • Gamma-Ray collimator 225 may be-configured adjacent to the source 220 in order to directionally constrain radiation from the radiation source 220 to an azimuthal radiation segment of the formation.
  • collimator 225 may include fins or walls 226, 228 adjacent source 220 to direct gamma ray propagation. By directing, focusing, or otherwise orienting the radiation from radiation source 220, radiation may be guided to a more specific region of the formation. Additionally, the radiation energy may be selected, by choosing different isotopic sources, so as to provide some lithological or spatial depth discrimination.
  • collimator 225 constrains radiation from source 220.
  • collimator 225 is also conically shaped as at 228, in the direction of detectors 240 to collimate the gamma rays from source 220.
  • collimator 225 may be configured in any geometry suitable for directing, focusing, guiding, or otherwise orienting radiation from radiation source 220 to a more specific region of the formation.
  • the radiation transmitted from source 220 into a formation is Compton scattered back from the formation to tool 200 where the back-scattered radiation may be measured by radiation detectors 240.
  • Radiation detectors 240 can be any plurality of sensors suitable for detecting radiation, including gamma ray detectors. In the illustrated embodiment, four detectors are depicted, although any number of detectors can be utilized. In another example embodiment, three detectors or six detectors are utilized; where optionally, each detector is disposed to "view" a different segment of the formation.
  • the tool can image the entire circumference of the casing 110 in separately identifiable segments. The resolution of the image of the overall circumference can depend on the number of detectors, the energy of the gamma rays and the degree of shielding provided around each detector.
  • gamma ray detectors may include a scintillator crystal that emits light proportional to the energy deposited in the crystal by each gamma ray.
  • a photomultiplier tube may be coupled to the crystal to convert the light from the scintillation crystal to measurable electron current or voltage pulse, which is then used to quantify the energy of each detected gamma ray.
  • the gamma rays' energies are quantified, counted, and used to estimate the density of material in a fracture.
  • Photomultiplier tubes may be replaced with high-temperature charge- coupled devices (CCD) or micro-channel photo-amplifiers.
  • Suitable scintillator crystals include, but are not limited to, Nal(Tl) crystals, BGO, and Lanthanum-bromide, or any combination thereof.
  • count-rates may be measured from returned radiation, in this case, returned gamma rays.
  • the intensity of the Compton scattered gamma rays depends on, among other factors, the density of the formation material. Hence, lower density represents gaps in the formation, such as may be caused by the formation being fractured and lower count- rates represent lower density as a result of fewer gamma rays being back-scattered towards the detectors.
  • detectors 240 are mounted inside a housing at a radius smaller than the radius of housing 230 inset from the surface of housing 230. Likewise, while they need not be evenly spaced, in the illustrated embodiment, detectors 240 are evenly spaced on the selected radius. Although the illustrated example shows four detectors 240 spaced apart 90 degrees from one another, those skilled in the art will appreciate that any number of multiple detectors can be utilized in the invention. Further, while the embodiment illustrates all of the detectors 240 positioned at the same distance from source 220, they need not be evenly spaced. Thus, for example, one detector (or a multi-detector array) might be spaced apart 12 centimeters from the source, while another detector (or a detector array) is spaced apart 20 centimeters from the source or any other distance within the tool.
  • detectors 240 can be positioned both above and below source 220.
  • collimator 225 would be appropriately shaped to guide gamma rays in the direction of the desired detectors.
  • additional shielding may be provided between the collimators to prevent radiation scattering (i.e. cross-contamination of the radiation) from different segments of the formation.
  • Each detector 240 may be mounted so as be shielded from the other detectors 240. While any type of shielding configuration may be utilized for the detectors 240, in the illustrated embodiment, collimator 248 is provided with a plurality of openings or slots 245 spaced apart around the perimeter of collimator 248. Although openings 245 could have any shape, such as round, oval, square or any other shape, in one example embodiment openings 245 are shaped as elongated slots and will be referred to as such herein.
  • a detector 240 is mounted in each slot 245, so as to encase detector 240 in the shield.
  • the width and depth of the slot 245 can be adjusted as desired to achieve the desired azimuthal range.
  • the length of slots 245 can be as long as the sensitive region of the gamma-ray detector (e.g. the crystal height). It will be appreciated that since a detector is disposed within the slot, the detector is not on the surface of the collimator where it might otherwise detect gamma rays from a larger azimuthal range.
  • slot 245 is 360/(number of detectors) degrees wide and the detector face to inner diameter of the pressure housing is a few millimeters deep (e.g. from about 2 to about 5 mm).
  • each slot is limited to 360/(number of detectors) degrees.
  • the view of each radiation detector 240 may be more focused on a particular region of the formation.
  • shielding eliminates or at least mitigates radiation scattered from one detector to another detector.
  • each detector is separated from one another by radiation absorbent material. By eliminating detector-to-detector radiation scattering, more precise azimuthal readings are achieved.
  • source collimator 225 is shown as a single, integrally formed body and conical surface 228, it need not be and could be formed of separate structural components, such as a source collimator combined with a detector collimator 248, so long as the shielding as described herein is achieved.
  • the region of housing 230 around the opening in source collimator and detectors 240 may be fabricated of beryllium, aluminum, titanium, or other low atomic number metal or material, the purpose of which is to allow more of the gamma rays to enter detectors 240.
  • This design is especially important for lower energy gamma rays, which are preferentially absorbed by any dense metal in the pressure housing.
  • an anti-coincidence algorithm may be implemented in electronics 260 to compensate for detector-to-detector radiation scattering. In this way, a processor can mitigate the effects of multiply-detected gamma rays via an anti-coincidence algorithm.
  • electronics 260, 262, and 264 are located above detectors 240 or below source 220.
  • Electronics 260 may include processor 262, memory 263, and power supply 264 for supplying power to gravel pack imaging tool 200.
  • Power supply 264 may be a battery or may receive power from an external source such as a wireline (not shown).
  • Processor 262 is adapted to receive measured data from radiation detectors 240. The measured data, which in certain embodiments includes count rates, may then be stored in memory 263 or further processed before being stored in memory 263.
  • Processor 262 may also control the gain of the photomultiplier or other device for converting scintillations into electrical pulses.
  • Electronics 260 may be located below source 220 and above detectors 240 or removed therefrom.
  • the tool further includes an accelerometer, a 3 axis inclinometer or attitude sensor to unambiguously determine the position of an azimuthal segment.
  • a compass device may be incorporated to further determine the orientation of the tool.
  • Fracture detection tool 200 may be constructed out of any material suitable for the downhole environment to which it is expected to be exposed, taking into account in particular, the expected temperatures, pressures, forces, and chemicals to which the tool will be exposed.
  • suitable materials of construction for source collimator 225 and detector collimator 248 include, but are not limited to, sintered tungsten (known as heavy-met), lead, dense and very-high atomic number (Z) materials, or a combination thereof.
  • FIG. 1 a 1 1 1/16 inch diameter configuration tool is illustrated in FIG. 1, the tool 100 can be sized as desired for a particular application. Those skilled in the art will appreciate that a larger diameter tool would allow more detectors and shielding to provide further segmentation of the view of the formation.
  • This tool may be deployed to detect fractures and to estimate their size.
  • a person of ordinary skill in the art with the benefit of this disclosure will appreciate how to relate the log results of count rates and inferred densities of formation material to the structure of the formation and to reason from the results to the condition of the properties of the detected fractures.
  • FIGS. 3A and 3B show cross-sectional views of another embodiment of the tool disposed in base pipe or production tubing 330, which is further disposed in casing 310.
  • An annulus 350 is defined between the casing 310 and the tubing 330, where FIG. 3 A shows a cross-section taken from the X-Y plane, which is perpendicular to the tool longitudinal axis, and where FIG. 3B shows a cross- section taken from the X-Z plane, along the tool longitudinal axis.
  • upper and lower source collimators 328, 329 are each conical shaped in the X-Z plane or Y-Z plane.
  • upper collimator 328 has a surface that defines an emission angle ⁇ with respect to the tool longitudinal axis ⁇
  • lower collimator 329 has a surface that defines an emission angle ⁇ 2 with respect to axis A x .
  • Detector 340 is shown in FIG. 3A in openings or slots 345, whereas radiation source 320 is shown depicted in FIG. 3B.
  • detector collimators 348 are fan-shaped in the X-Y plane and rectangular in the X-Z or Y-Z planes.
  • upper and lower conical source collimators 328, 329 reduce multiple scattering events in unwanted regions surrounding the tool and creating un-necessary background.
  • the conical upper and lower source collimators 328, 329 causes radiation from the source to be directed from the source 320 and single scatter from the wellbore wall (or gravel pack) to the detectors 340.
  • the shape of the upper and lower source collimators 328, 329 and selective positioning of the detectors 340 from the source 320 vastly increases the number of counts detected by the detectors 340 of radiation that have single scattered (rather than undergone multiple scatters) so that resolution of the gathered data can be increased, thereby providing data that better represents the downhole formation.
  • the angles ⁇ ⁇ 5 ⁇ 2 are chosen so that the tool 10 can be put in different sized wellbores; where the spacing between the source 320 and detectors 340 is adjusted to ensure single scattering is detected in the varying diameter wellbores.
  • Suitable values of the emission angles ⁇ 1; ⁇ 2 range from about 15° to about 85°, and all values between 15° to about 85°, and wherein the lower value of the range of emission angles ⁇ 1; ⁇ 2 can be 15° to about 85° (and all values in between), and wherein the upper value of the range of emission angles ⁇ , ⁇ 2 can be 15° to about 85° (and all values in between).
  • suitable source to detector spacing include, but are not limited to, from about 1 inch to about 12 inches, and all values between 1 to 12 inches.
  • the downhole tool is capable of measuring count rates while being lowered or raised in the wellbore.
  • the downhole tool may perform measurements while the tool is stationary in the wellbore.
  • Exemplary raising and lowering rates include displacement rates of up to about 1800 feet/hour.
  • FIG. 4 illustrates in a partial side sectional view, an example of an imaging tool 400 inserted within a tubular 402.
  • the tool 400 can be the same or substantially the same as the tools 100, 200 respectively of FIGS. 1, 2, and 3 and described above.
  • the tubular 402 is inserted into a wellbore 404 that is shown intersecting a subterranean formation 406.
  • Casing 408 is optionally provided in the wellbore 404 for lining the sidewalls of the wellbore 404.
  • the tubular 402 is production tubing.
  • the tool 400 is deployed in the wellbore 404 on a line 410, where the line 410 can be a wireline, slickline, cable, or coiled tubing.
  • the line 410 is shown inserted through a wellhead assembly 412 that is mounted on surface above an opening to the wellbore 404.
  • Fluid 413 is illustrated in the tubular 402 and surrounding the space between the tool 400 and walls of the tubular 402.
  • fractures 414 in the formation 406 surrounding the wellbore 404 are fractures 414 in the formation 406 surrounding the wellbore 404.
  • fractures 414 define a discontinuity in the formation 406 that may occur where adjacent portions of rock or other subterranean strata shear from one another.
  • lengths of the fractures 414 can range from less than a foot, to in excess of many feet.
  • the presence of the fractures 414 can be detected with the tool 400.
  • included with the embodiment of the tool 400 of FIG. 4 is a radiation source 416, which can be substantially the same as sources 220, 320 respectively of Figures 2 and 3B and described above. Further in the example of FIG.
  • a sensor 418 is included with the tool 400, wherein the sensor 418 includes detectors 140, 240 respectively of FIGS. 1 and 3 and discussed above.
  • Radiation emitted from the source 416 can travel along a path represented by arrows A, which initially diverges from the axis A x . Some of the radiation undergoes scattering and is redirected to converge with the axis ⁇ at a location axially away from the source 416. As shown, the redirected radiation contacts sensor 418 where a count and associated energy of the radiation is detected.
  • the radiation is directed in a conical pattern away from the source 416 and generally about a line intersecting the source 416 and sensor 418.
  • the radiation Compton scatters from the fluid 413 in the tubular 402, an area proximate the sidewall of the tubular 402, and the formation 406. At least some of the radiation scatters from materials in the fractures 414. It should be pointed out that paths the radiation follows from the source 416 to the sensor 418 are not limited to the select number of arrows A that are illustrated for clarity.
  • the energy of the radiation detected by the sensor 418 is affected by the Compton single-scatter angle of the radiation (i.e. the angle of the directional change of the radiation).
  • the energy decreases with increasing scattering angles ; thus the radiation flowing from the source 416 to the sensor 418 which undergoes only minimal scattering will have a greater detected energy than the radiation single scattered over a large angle from adjacent the tubular 402 the formation 406.
  • the radiation single scattered from adjacent the tubular 402 will have a greater detected energy than the radiation single scattered from the formation 406 because the average angles are shallower.
  • radiation counts detected by sensor 418 are binned based on an energy level of each count.
  • source 416 and sensor 418 are set apart a designated distance so that the gamma rays from the source 416 scatter from a region 420 at the wall of the wellbore 408.
  • the range of the region 420 from which the gamma rays from the source 416 scatter extends radially outward past the wall of the wellbore 408 and to within the formation 406.
  • Region 420 can be an annular space circumscribing the wellbore 404 and having a radial thickness ranging from a few inches to several feet. Detecting the actual number of Compton scattered gamma rays per unit time provides an indication of the density of material from which the gamma rays have scattered. Moreover, material filling a fracture 414 generally has a density different from the surrounding formation 406. Thus, a change in rate of gamma rays detected by sensor 418 can indicate that a fracture 414 is at the wall of the wellbore 404 or in the region 420.
  • the tool 400 is raised within the wellbore 404 on wireline 410 while gamma rays emitted from the source 416 Compton scatter from the wall of the wellbore 404 and/or from within the region 420 around the wellbore 404.
  • the location of scatter can depend on the relative locations of the source 416 and sensor 418.
  • a fracture 414 at the wall of the wellbore 404, or in the region 420, can be identified by a change in the rate of gamma rays detected by sensor 418.
  • a height or width of a fracture 414 can be estimated.
  • Advantages of using the method and tool 400 described herein include that fractures are identifiable with gamma ray detection that are outside the size range detectable by known acoustic means.
  • An additional advantage of utilizing Compton scattering of gamma rays to identify fractures 414 in the formation 406 surrounding the wellbore 404, is that their vertical and azimuthal locations can be identified with precision, as well as their size.
  • strategically placed perforations 422 can be formed in the formation 406 based on precise spatial information of the fractures 414 derived from use of the tool 400 described above.
  • An example embodiment of a perforating string 424 is shown disposed in the wellbore 404 for forming the perforations 422.
  • the string 424 includes a series of perforating guns 426 with shaped charges 428. In the example of FIG.
  • the shaped charges 428 are disposed at a depth in the wellbore 404 and oriented so that when they are detonated, an ensuing metal jet (not shown) creates perforations 422 across the wall of the wellbore 404 and into the formation 406 to intersect with the fractures 414.
  • the tubular 402 lining the wellbore 404 is wellbore casing, and cement 430 is disposed in the annular space between the casing and wall of the wellbore 404.
  • the perforation 422 also extends through the casing and the cement 430. The intersection between the perforations 422 and fractures 414 create fluid communication between fractures 414 and the wellbore 404.
  • Embodiments exist wherein the formation 406 is a shale formation adjacent a formation (not shown) having a hydrocarbon bearing reservoir; and wherein a fracture 414 extends into the adjacent formation and into communication with hydrocarbons therein.
  • intersecting fracture 414 that extends into the adjacent formation with a perforation 422 necessarily communicates the wellbore 404 with the hydrocarbon bearing reservoir.
  • FIG. 6 an example of the imaging tool 400 is illustrated disposed in wellbore 404 and imaging the formation 406 around the wellbore 404; where the steps of imaging the formation 406 can be the same or similar to that described above and illustrated in Figure 4. Further as described above, the tool 400 is moved within the wellbore 404 during imaging so that data from the formation 406 can be gathered at multiple wellbore depths. Analyzing the gathered data can provide information about the material within perforations 422 and/or fractures 414 in the formation 406. In an example, the information about the material includes the density of the material.
  • Time lapsed imaging includes performing a baseline measurement made at an initial time with the tool 400, and then conducting subsequent measurements with the tool 400; any changes between imaged data obtained at different times can be used to estimate density changes.
  • permeability of the perforations 422 and fractures 414 can be affected by the density of the material in the perforations 422 and fractures 414, monitoring changes in density of this material can therefore yield information about changes in permeability of the perforations 422 and fractures 414.
  • imaging the formation 406 with the tool 400 can be used to determine which the perforations 422 and fractures 414 have undergone deterioration by using a time-lapse differential profile logging technique. Information about deterioration, or lack of deterioration, can enable well operators to plan remedial operations.
  • any changes in size of the perforations 422 and fractures 414 can be monitored.
  • Size changes of the perforations 422 and fractures 414 can include one or more of thickness, width, length, and combinations thereof.
  • the perforations 422 and fractures 414 define voids in the formation 406.
  • a differential log profile is generated that depicts the difference between a base-line logging measurement done early in the life of the well, and subsequent measurements made after the well has been used for some time. Differences in the fracture density profiles can indicate changes in the fractures caused by re-injection processes.

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Abstract

Selon l'invention, des vides adjacents à une paroi de puits de forage et dans une région entourant une paroi de puits de forage peuvent être détectés par le contrôle de rayons gamma dispersés à partir des fractures. Des rayons gamma sont dirigés de façon stratégique à partir d'un outil disposé à l'intérieur du puits de forage et vers la paroi et/ou la région. Certains des rayons gamma se dispersent à partir des vides, et sont détectés à l'aide de détecteurs établis à une distance axiale désignée à partir de la source de rayons gamma. En plus de l'identification de la présence des vides, l'emplacement et la taille des fractures/perforations sont également estimés. Une imagerie intermittente de la paroi du puits de forage peut produire des changements dans les vides, ceux-ci pouvant eux-mêmes affecter la perméabilité du puits. Des exemples des vides comprennent des fractures et/ou des perforations.
PCT/US2015/035821 2014-06-16 2015-06-15 Procédé pour évaluer des vides dans une formation souterraine WO2015195552A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12000266B2 (en) 2020-03-13 2024-06-04 Geonomic Technologies Inc. Method and apparatus for measuring a wellbore

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3862418A (en) * 1972-11-15 1975-01-21 Kenneth Preiss Apparatus and method for using the same to ascertain the angular position of a discontinuity in the medium surrounding a test bore
US4342911A (en) * 1979-12-28 1982-08-03 French Lewis L Focused nuclear interface survey instrument and method of determining density changes in mining and storage wells
US20130009049A1 (en) * 2009-07-01 2013-01-10 Ge Oil & Gas Logging Services, Inc. Method For Inspecting A Subterranean Tubular
US20130043381A1 (en) * 2009-07-01 2013-02-21 Ge Oil & Gas Logging Services, Inc. Method for detecting fractures and perforations in a subterranean formation
WO2014055712A2 (fr) * 2012-10-04 2014-04-10 Ge Oil & Gas Logging Services, Inc. Procédé de détection de fractures dans une formation souterraine

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3862418A (en) * 1972-11-15 1975-01-21 Kenneth Preiss Apparatus and method for using the same to ascertain the angular position of a discontinuity in the medium surrounding a test bore
US4342911A (en) * 1979-12-28 1982-08-03 French Lewis L Focused nuclear interface survey instrument and method of determining density changes in mining and storage wells
US20130009049A1 (en) * 2009-07-01 2013-01-10 Ge Oil & Gas Logging Services, Inc. Method For Inspecting A Subterranean Tubular
US20130043381A1 (en) * 2009-07-01 2013-02-21 Ge Oil & Gas Logging Services, Inc. Method for detecting fractures and perforations in a subterranean formation
WO2014055712A2 (fr) * 2012-10-04 2014-04-10 Ge Oil & Gas Logging Services, Inc. Procédé de détection de fractures dans une formation souterraine

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
E. D'HUTEAU, OILFIELD REVIEW, vol. 23, no. 3, 2011

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12000266B2 (en) 2020-03-13 2024-06-04 Geonomic Technologies Inc. Method and apparatus for measuring a wellbore

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