Non-rotating logging-while-drilling neutron imaging tool

Non-Rotating Logging-While-Drilling Neutron Imaging Tool

Background of the invention

The invention relates generally to the field of imaging rock formations. More specifically, the invention relates to systems and methods for obtaining neutron images of rock formation using a tool that does not require rotation while drilling and/or does measurement.

For several decades, neutron tools have been used to measure neutron porosity and the hydrogen index found in earth formations. Modern instruments use pulsed neutron sources and/or epithermal neutron detectors and thermals to measure the neutron flux of neutrons at multiple distances from the neutron source. Additionally, the time reduction measured by one or more detectors is a shallow measurement hydrogen index and is very sensitive to stopping. Traditional porosity measurement is based on the fluid filling the pores from a proportion of neutron fluxes from two different distances from the source.

These neutron instruments have been widely used in the petroleum chemical industry, in particular during the process called LWD (Logging While Drilling) or MWD (Measurement While Drilling) phase, but also at other stages in Wireline cable. . LWD/MWD is a recording of performance during the initial phase of drilling a hole within the geosphere and in particular an identified hydrocarbon reservoir that ultimately forms productive oil or gas that meets energy requirements. Figure 1 is an illustration of an exemplary wellsite system according to an illustrative model. The well can be located on land or in water. In said illustrative system, wellbore 11 is formed in subterranean formations by rotary drilling in the well known manner.

The drill string 12 is suspended inside the drill hole 11 which includes a bottom hole assembly 100 which includes the drill bit 105 at the low end thereof. The surface system includes the platform and derrick assembly 10 mounted on the hole 11, and the assembly 10 includes a rotary table 16, a kelly pull stem 17 and a rotary swivel 19. The drill pipe string 12 is rotated by a rotary table 16 to which power is supplied by means not shown and which engages with the intake stem 17 at the upper end of the drill pipe string. The drill pipe string 12 is suspended from the hook 18 and is attached to a movable block (not shown) within the draw stem 17 and swivel link 19 that allows the drill pipe string to rotate relative to the hook.

As is well known, a top drive system can alternatively be used.

In the example of this embodiment, the surface system also includes drilling fluid or mud 26 that is stored in the hole 27 formed at the well site. The pump 29 delivers the drilling fluid 26 to the interior of the drill string 12 through a port in the swivel 19, which causes the drilling fluid to flow downstream through the drill string as shown by the directional arrow. 8. Drilling fluid exits the drill string 12 through ports in the drill bit 105 and then circulates upward through the annulus region between the outside of the drill string and the wall of the drill hole as shown by directional arrow 9. In the well-known method, the drilling fluid lubricates the drill bit 105 and carries formation cuttings to the surface where they return to the drill bit 27 for recycling.

The bottom hole assembly (BHA) 100 of the shown embodiment includes a logging-while-drilling (LWD) module 120, a measuring-while-drilling (MWD) module 130 and a steerable system Rotary, motor and drill bit 105. The LWD 120 module is included in a particular type of drill collar known in the art which may include one or more of a plurality of known types of performance recording devices. It will also be understood that more than one of the LWD and/or MWD modules may be used, for example, as shown at 120a (a module at position 120 may be referred to throughout this document as an alternative means module at Position 120a, also). The LWD module includes capabilities for measuring, processing, storing information, and communicating information with surface equipment. As an example of the present disclosure, the LWD module can include a measuring basket or neutron measuring instrument for measuring, for example, the porosity of the surrounding formation.

The module for the MWD 130 may be embedded in a type-specific collar or drill collar as known in the art, and may include one or more means for measuring the characteristics of the wireline and drill bit. The MWD tool may also include a device (not shown) for generating electrical power for the downhole system. This may typically include a turbine generator supplied with power by the flow of drilling fluid, and it may be understood that other power systems and/or battery systems may be used. In the present embodiment, the MWD module includes one or more of the following types of measuring devices: a weight-on-bit measuring device, a torque measuring device, and a vibration measuring device device, shock measuring device, stick slip measuring device, direction measuring device, and inclination measuring device.

Figure 2 shows a logging-while-drilling nuclear device as described in US Patent No. RE. 36.012 which is used in the form of an accelerator-based source, and it is understood that other types of nuclear LWD tools may be used in the form of an LWD tool 120 or part of an appropriate LWD tool 120a. In Figure 2, the collar portion 1040 is shown as a stainless steel tool body 1054. In this structure of steel 1054, towards one side of the longitudinal axis (not visible in this projection) is a mud channel extended longitudinally to transport drilling fluid towards the lower part of the drill string. Off-center on the other side of the steel structure 1054 are a neutron accelerator 1058, an associated control device, a high-voltage electronics package 1060, and distally displaced and aligned detectors 1062. The proximally displaced detector 1062 is responsive. Mainly for detection output with minimal configuration effect. The detection 1062 is surrounded preferably on all surfaces except those adjacent to the accelerator 1058 by a shield 1064 of neutron absorbing material mediated by the neutron. The output of the internal detector 1062 was used to make the detector normal to the source strength fluctuation output of the other detectors. The longitudinally adjacent portion of the near-spaced detector 1062 is a plurality of patterns or plurality of detectors of which 1066a and 1066b are illustrated in this figure. The detector 1066a is a back-shielded as shown at 1068a.

The arrangement includes at least one part, and preferably more than one part, of an epithermal neutron detector at at least one gamma ray detector shown in the example at 1084 with a shield 1086. A device may also be included One or more thermal neutron detectors. US Patent No. RE 36,012 may be referred to for additional details. Detector signals can be used to determine, among other things, the density, porosity and rock properties of a formation.

As a person skilled in the art can understand from the benefit of the present disclosure, in conventional LWD wellsite systems, such as those described above when referring to Figures 1 and Figure 2, the entire drill string 12 rotates in Mostly during the drilling process, whether it is through the Kelly 17 pull stem system or the top drive system. Additionally, in well-place LWD systems that include a nuclear tool, such as the LWD tool 120 described above, the tool 120 may be part of the BHA 100 that rotates during drilling operations.

As a result, in nuclear LWD, conventional imaging measurements are made to accommodate the fact that the instrument is rotating in the borehole, and azimuthally focused measurements are made thus obtaining an azimuthal scan of the surrounding formation as the instrument rotates.

In the absence of tool rotation, i.e., when the tool is sliding, none of these tools can be obtained. In addition, no LWD systems have been developed in recent years in which the entire drill string does not rotate or rotate but only slowly, such as rotating at the bottom of the hole motor and/or tubular drilling is used, which is important By further effectiveness with spin-based neutron imaging in LWD applications. As a result, there is a need in the field for neutron imaging methods and systems that overcome one or more of the drawbacks of conventional methods.

General description of the invention

In one of the features, a well logging instrument is provided. The well performance logging device may include a neutron source and a first set of neutron detectors. The first set of neutron detection methods may have been azimuthally separated from each other.

In another aspect, a method for recording wellbore performance is provided. The method comprises placing a performance logging instrument in the borehole and measuring at least neutron porosity in the borehole in a range of azimuthal orientations while the instrument remains substantially fixed in the azimuthal orientation.

Other features and advantages of the invention will be apparent from the following description and subsequent claims.

Brief explanation of the drawings

Figure 1: Illustration of a demonstration system at a well site.

Figure 2: Shows a nuclear method for recording performance while drilling using an accelerator-based source.

Figure 3: shows the well drilling system according to an illustrative model.

Figures 4a-4c: Different views of the neutron imaging tool according to an illustrative model.

Figures 5A-C: Schematically different views from a neutron imaging instrument according to an alternative illustrative model.

Figures 6a and 6b: Alternative cross-sections of a neutron imaging instrument according to the illustrative models.

Figure 7 shows a cross-section and an alternative neutron imaging device according to an illustrative embodiment of the invention.

Figures 8a-c: Schematically different views of the neutron imaging instrument according to an alternative illustration model.

Figure No. 9: A cross-sectional section of the neutron imaging instrument according to an illustrative model.

Figure 10 is a cross-sectional section of the imaging tool 1000 according to an alternative illustrative embodiment.

Figure 11: Shows a cross-section of the azimuthally sensitive neutron imaging detector 1100 according to an illustrative model.

Detailed description

The invention provides the possibility of obtaining neutron images and data regarding rock formation using a tool that does not require rotation during drilling and/or measurement. Methods and systems for obtaining neutron-based images will now be described with reference to Figures 9-36 which show representative embodiments or illustrative embodiments of the invention. As described above, there are well location systems in the neutron imaging tool that may not be necessary to rotate while taking measurements. Several non-exhaustive examples include situations in wellsite systems including wireline systems and logging-while-drilling systems in which the entire drill string cannot rotate. These LWD systems may include systems with mud motors or other downhole motors for powering the drill bit and coiled tubing of the drilling systems. LWD systems may also include conventional LWD systems during sliding operations other than drilling operations. However, an important portion of the following disclosure may be referred to as coiled tubing of drilling systems and the discussion is intended as an example only. As a person of ordinary skill in the art may know after making use of the present disclosure, the models illustrated herein can be applied to many other systems in the human setting since the neutron imaging tools do not need to rotate.

Referring generally to Figure 3, which is illustrated in the drilling system in humans according to an illustrative embodiment, one or more embodiments of the drilling system 320, may be illustrated in a form operated in order to drill a drill hole 322 for use in the eye 324. The drilling system is In the wellbore 320 is a coiled tube drilling system that forms part of the overall coiled tube drilling mounting device 326. The coiled-tube assembly 326 can have numerous components and systems, but the described system generally includes a coiled-tube drilling tower and an injector installation 328 positioned at surface 330 close to the top of the well 324. The drilling system 320 generally includes coiled-tubing 332 connected to the bottom hole assembly of coiled tubing 334 through the orienter 336. As shown, the guide device 336 is attached to the inner hole assembly 334 at the upper portion or end of the upper portion 338 of the lower hole assembly. Alternatively, the downhole assembly 334 may be mounted at the top of the guide device 336, which can result in the downhole assembly 334 may be mounted above the guide device 336, which can result in a downhole assembly that does not rotate properly. Absolutely repetitive. In addition, the drill bit assembly 334 includes a variety of components but generally includes a drill bit 340 that is driven in order to form a hole 322. The drill bit 340 may be rotated by the motor 342, for example, Drill motor or other suitable driving device. In this embodiment, the motor/device 342 is a steering device, such as a steerable mud motor, which can be directionally controlled to drill hole 322 along a plurality of desired paths through the reservoir 344. The coiled tubing bottom hole assembly 334 contains a variety of components depending on the medium of intended use. As discussed in detail below, the bottom hole assembly may have a plurality of sensors and signal transmission systems to provide real-time operator data and/or other useful data both in the drilling hole 322 and in Low hole assembly guidance.

For example, downhole assembly 334 can include measurement while drilling systems and/or logging while drilling systems as described above. For example, the LWD tool 321 such as the neutron imaging LWD tool may be positioned within the lower hole assembly 334, in which case the tool 321 may not rotate during drilling operations as it is at the top of the mud motor 342 Which rotates from the drill bit 340.

Figures 4a-4c are schematic views of the neutron imaging tool 400, according to an illustrative model. Figure 4a shows a neutron imager 400 in the longitudinal cross-section, whereas Figures 4b through 4c show the neutron imager 400 in the transverse sections at different axial positions. In many illustrative embodiments, as can be seen by a person skilled in the art, the neutron imaging instrument 400 may include a variety of different instruments, which may be capable of obtaining measurements of the composition in order to determine neutron porosity, The hydrogen index, rock properties, and other formation-specific characteristics using a neutron source and detecting neutrons and/or gamma-rays. This can include gamma-rays spectroscopy measurements, as well as time-based measurements, such as the determination to obtain the macroscopic thermal neutron in the cross-section of the formation hole (Sigma), or the slowness of the epithermal neutron with respect to time and the special measurement. The neutron gamma density (in US patents Nos. 608.215/5 and 804.820/5). Additionally, disruption can be determined and a combination of stand off measurements at different azimuths can be used to determine the diameter and, in the case of detectors, at more than two azimuths of the drill hole shape. In an example embodiment, the neutron imaging tool 400 may also be used to analyze neutron-based metrics collected for image extrapolation or composition scanning. Although in certain embodiments and/or in certain cases it may be preferable to have any other detector. Where preferred 3He detection methods may be used in certain embodiments and/or in cases or in any other suitable detection means for thermal neutrons or epithermal neutrons such as Li glass, a 10B-lined proportional counter and the like.

The exemplar neutron imaging tool 400 includes a set of structural components. The first part of the neutron imaging tool 400 can include the collar 404, the mud channel 406, the pressure housing 408, and the neutron source 410 within the pressure housing 408 of the neutron source portion of the imaging tool. tool 400. Quantum sleeve 404 can provide encapsulation for the neutron imaging tool 400 and mud channel and can be made from a variety of channels such as high-strength steel (which is typically non-magnetic), or high-strength Ni alloys. -Alloys or Titanium, a few of which have been mentioned. In the case of neutron tools, it can be useful to use materials with small absorption in the cross sections of epithermal neutrons or thermal neutrons in order to increase the number of neutrons with the detection method(s). Mud channel 406 can provide a channel through which drilling mud flows into the neutron imager 400. The pressure housing can function to maintain a low pressure in the medium of the neutron source or the sensors and electronics in which it is contained. It can be made of materials such as high-strength steel, Ni alloys, or other materials suitable to withstand the harsh environment beneath humans. Withstand downhole pressure.

A second part 412 of the neutron imaging tool 400 can include continuing components of the first part 402, such as the collar 404 and the mud channel 406. As shown in FIG. 4a, the collar 404 can extend straight Within a first part and a second part 402 and 412 of the neutron imaging means 400, while the silt channel 406 may have an angle that converges toward the center neutron imaging tool 400 from the first part 402 toward the second part 412. This extension or angular portion may be accomplished by a flow diverter 414. A second portion 412 of the neutron imager 400 may include a rigid structure 416 and a plurality of neutron detectors 418. The steel structure 416 may provide a special structure for mounting and/or stabilizing neutron detectors 418 on it and in order to protect the components installed in the steel structure from high pressure fluid in the mud channel. It may be made of materials such as steel. High-resistance Ni and Titanium alloy or any other materials suitable to withstand the downhole environment and withstand downhole pressure.

In the embodiment shown, four of the neutron detectors 418 are offset at an azimuth of about 90 degrees at the intervals where other suitable arrangements are possible. In various illustrative embodiments, the one or more neutron sources may include a radioisotope source or an electronic neutron generator such as a dT generator. In certain embodiments, specifically if an electronic neutron generator is used, a neutron monitor (not shown) may be installed adjacent to the neutron generator in order to measure (variable) neutron flux ) flux neutrons in order to allow for the equality of the detecting neutrons method that works on calculating the number of neutrons that emerge from the source 410.

Additionally, in an alternative embodiment, the number of edge-mounted neutron detectors 418 can be as few as two detectors 418. In certain embodiments, two detectors 418 may be included if possible The neutron imaging tool 400 shall be directed in such a way that the detection means 418 are directed toward the preferred azimuth. For example, in many cases, trends can be converted to an uptrend or a downtrend. However, in many other cases (for example, in the case of a wellbore that is not of a regular shape), other azimuthal orientations may be preferred, which a person skilled in the art can recognize from the benefit of the present disclosure. . In certain embodiments, particularly when the orientation of the neutron imaging tool 400 cannot be easily controlled, it may be advantageous to include four or six neutron detectors 418 that are azimuthally spaced apart Some. In instruments 400, additional neutron detectors 418 having large diameters can be included. Neutron detectors may include sensitive neutron detectors.

Neutron detection devices 418 may be either epithermal neutron detectors or thermal neutron detectors. Traditionally, many neutron methods that use thermal neutron detection methods are used in order to achieve the maximum possible calculation rates and thus the best accuracy. In addition, hot detectors allow sigma measurement. On the other hand, epithermal detectors, with lower neutrons, are less sensitive to the presence of neutron absorbers in the drill hole or formation. A neutron shielding device 520 may be used between the source 410 and the detection means 418 in order to reduce the possibility of neutron transfer directly from the source 410 to the detection means 418.

Another advantage of having multiple sensors at different azimuthal orientations is the ability to achieve measurements in order to provide neutron imaging without the need for rotation of the instrument 400 or other object on which neutron detectors 418 are located. In other words, the neutron intensity instrument 400 (and neutron detectors 418) can maintain substantially the same azimuthal orientation while obtaining the necessary measurements from a range of azimuthal orientations. In certain embodiments, a substantially constant trend does not require the tool 400 to remain substantially in the same direction over the relevant time period, but describes a situation in which the tool 400 does not have significant rotation and/or is not intended to rotate but This may be done unintentionally, such as with the tool 400 moving axially within the hole or similar medium. In this way, the neutron imaging tool 400 can be used using conventional LWD systems, which involve rotating the drill cable string or rotating the downhole assembly in order to provide neutron measurements such as neutron porosity and hydrogen index. of the formation of interest while drilling, whether in the rotating or non-rotating mode (e.g., while sliding). Additionally, the Neutron Imager 400 can be used with other LWD systems such as coiled tubing systems or other LWD systems with down-hole motors where the drill cable assembly and/or BHA are not rotating. If the instrument rotates slowly, as may be the case in a coiled tubing system, the instrument can have features for both non-rotating and rotating measurement. It must be understood that any of these measurements can be based on measuring azimuthal orientation at the same time as the measurement.

Figures 5a-c are various schematic views of the neutron imaging tool 500 according to an illustrative model. Figure 5a shows the neutron imager 500 in a longitudinal cross-section, while Figures 5b and 5c show the neutron imager 500 at cross-sectional sections and at various axial positions. The primary difference between the neutron imager 400 of Figure 4 and the neutron imager 500 of Figure 5 is that the latter includes two detectors assemblies 418 and 419. In an example embodiment, the neutron imaging instrument 500 may also include a neutron monitor (not shown) for measuring (variable) flux of neutrons and to allow the return of the neutron detector 418, 419 in its normal state with other equipment in relation to the number of neutrons that are emitted from the source 410. The neutron monitoring device may be, for example, a plastic scintillation detector as described in US Patent 884,994/6, or it may be a semiconductor detector (SiC, diamond), or A gas counter filled with a gas, such as hydrogen, helium (4He), or any other suitable forms that can be identified by a person of ordinary skill in the art after making use of the present disclosure. In illustrative embodiments using two or more exploration groups 418 and 419, a correction may be provided for certain effects resulting from the discontinuation of the exploration means such as unknown borehole size or lack of good knowledge of the borehole fluid composition. This may be possible when discontinuity exists and when there are different amounts of mud between adjacent detectors and the wellbore walls versus distal detectors and the wellbore wall. These differences can be used to approximate and correct the failure mode.

Additionally, in certain embodiments the number of neutron detectors 418 and 419 may be unequal at different axial positions along the neutron imaging tool 500. Azimuthal resolution at a shorter distance may be better and thus a greater number of Detection means 419 (e.g., eight detection means) may be distributed along the edges of the tool 500 at a proximal position and fewer (e.g., four) detection means 418 may be distributed at a proximal position. In illustrative embodiments, it can be advantageous to have near and far detection means 418 and 419 at the same or near the same azimuthal axis. In alternative embodiments, it may be possible to position the detection means 418 and 419 at the same azimuth dimensions in two separate positions.

Figures 6A-6B show alternate cross-sections of the neutron imager 600 and 601 according to illustrative embodiments. Figures 6a and 6b show options for protecting detectors with neutron 418 to improve their azimuthal sensitivity. In other embodiments, as shown in Figure 6A, each detector 418 may be equipped with a neutron shield 520 that reduces the possibility of neutrons entering from the side or rear. The mentioned shield 520 can be used as a neutron absorber. Typical materials can be natural boron, for example, for enhanced performance, or boron enriched with 10B isotope. Boron can be in its elemental form or in a chemical compound such as B4C. Typically, the absorber may be in the form of a packaging that may be in the form of a matrix of various materials. Alternatively, the material can be embedded in an elastomer or mixed with epoxy to give a smaller number of patterns. Instead of boron or enriched 10B, other neutron absorbers can be used such as 6Li, Cd, or Gd to be a few examples.

Figure 6b shows variation options for the shielding neutron detectors 418 that are used either additionally or in place of the neutron shields 520 of Figure 6a. The emplacement embodiment includes the neutron shielding 520 of Figure 6a and additionally the quantum sleeve collar 404 or external shielding 622 which may be placed on the quantum sleeve collar 404 in order to reduce the number of neutrons entering the detector 418 from directions other than desired. Additionally, in illustrative embodiments, the collar 404 may be fabricated from a thinner portion of the detection device 418 in order to reduce neutron scattering and absorption, thus creating neutron windows 624. In certain illustrative embodiments, neutron windows 624 may To be filled using a material with a small cross-section of neutron absorption or scattering which can reduce the effect of the downhole fluid on the measurement taken by neutron detectors 418. These materials can include compounds such as PEEK or PEKK that have a lower hydrogen content compared to the borehole fluid, or metals in the low neutron absorption cross section. In a different alternative embodiment, neutron windows 624 or other thinning may be located within the sleeve collar 404.

Figure 7 shows an azimuthal cross section of an alternative neutron imaging tool 700 according to an illustrative embodiment. As shown in Figure 7, the neutron detectors 418 and 419 may be mounted within the mandrel section 726 of the neutron imager 700 other than those mounted on the steel structure 416 (as shown in Figures 4-6). ). This design may be necessary if the neutron detection means 418 and 419 are difficult to mount on the steel structure 416 or collar 404. Additionally, the installation of neutron detection devices 418 and 419 in the mandrel 726 may allow one or more gamma-ray detectors (not shown) to be effectively installed for spectroscopy measurement. It is preferable to place gamma-ray detection methods in the mandrel section 726 in tools that have a smaller diameter, as they allow the use of larger and more effective detection methods than gamma ray detection methods. The available diameter of the mandrel is generally larger than that of the steel body 416 or collar 404 in tools where the mud channel 406 in the steel body 416 is typically on or near the axis of the tool. The centered mud channel 406 is useful as a device with detectors at multiple azimuths as it ensures the required uniformity in measuring the various detectors and allows room for independent installation when installed independently of the chosen azimuths. Installing the neutron detectors mentioned 418 and 419 in the mandrel section 726 has some disadvantages. For example, the increased distance of detectors 418 and 419 from the formation can reduce the neutron detection probability and azimuth sensitivity. Four detection means 418 and 419 are installed in the mandrel portion 426 with neutron shields 520 placed within the mandrel portion 726 and also for azimuthal sensitivity. In other embodiments, additional shielding (not shown) may be used on the outside of the collar 404 and pressure housing 408 to improve concentricity. In an alternative embodiment, the plurality of neutron detection means 418 can be replaced by a multi-wire detector (not shown) in order to simplify the structure.

Figures 8a-c are schematically different projections from the neutron imaging tool 800, according to an alternative illustrative model. Figure 8a shows a neutron imaging tool 800 in the longitudinal cross section, while Figures 8b and 8c show a neutron imaging tool 800 in the cross sections at different axial positions.

The difference is between the neutron imaging devices 400 and 500 of Figures 4 and 5 and the neutron imagers 800 of Figure 8, which are the neutron detectors 418 and 419 of the neutron imaging device 800 which are mounted in the collar 404 itself. This design can give higher neutron sensitivity and better azimuthal resolution due to the neutron detection means being partially installed 418 and 419 close to the formation. In an example embodiment, electronic means (not shown) of neutron detectors 418 may also be mounted in the collar 404. In such an embodiment, feedthroughs may be required in order for signals taken from the neutron detection means 418 and 419 to be accessed in the solid structure 416.

Similarly, to embodiments discussed above, detectors 418 and 419 may be back-shielded 520 to enhance azimuthal sensitivity. In certain embodiments, where there is sufficient room for a backshielding or if additional enhancement of azimuthal sensitivity is required, external neutron shielding 622 may be used between two detection means 418 and 419 on the collar 404. Alternatively, as shown in Figure 9 which is a cross-section of a neutron imaging tool 900 according to the illustrative embodiment, the steel structure 416 may be enclosed with a neutron shielding 928 comprising a neutron absorbing material such as Various corresponding compounds of various isotopes of boron or other suitable substances which may be recognized by a person of ordinary skill in the art after making use of the present disclosure.

In one embodiment, the detection means 418 are mounted in the sleeve 404 such as the embodiment shown in Figure 9. The neutron detectors 418 may be mounted in machined slots under the protective cover. Each or potentially all of the detection means 418 may be mounted at an azimuthal position in the pressure housing 408 prior to installation on the tool 900. Alternatively, when possible, the neutron detectors 418 may be mounted in axial holes in the collar 404. This design may allow for installation without the pressure housing 408 around the neutron detectors 418.

Figure 10 is a cross-section of the neutron imaging tool 1000 according to an alternative illustrative embodiment. The model of Figure 10 differs from Figure 9 primarily by the single neutron detectors 418 of Figure 9, which are replaced by azimuthally sensitive neutron detectors comprising multi-wire detectors. wire detectors 1030. The various wire detection methods mentioned 1030 can allow azimuthal readouts. These positions are position sensitive or azimuthally sensitive detectors and may be supplemented with additional neutron shielding on the outer portion (not shown) to improve azimuthal sensitivity, in addition to the outer shielding and internal 622 and 928 discussed above.

Figure 11 shows a cross-section of an alternative model of the neutron detectors 1030 from Figure 10, according to an illustrative model. As shown in Figure 11, the position sensitive detector may consist of a plurality of neutron detectors 1132 (tubes lined with 3He, 10B) that are positioned in array 1134 with wire 1136 placed thereon. Figure 11 allows for epithermal mixing and partial use of neutron detectors. Specifically, if a neutron detector is protected from neutron entry from the back, the inner layer(s) of the detector could be more sensitive to epithermal neutrons as the outer detectors are absorbed in a larger distillation fraction than the thermal neutrons thermal neutrons.

As can be known by a person of ordinary skill in the art and after making use of the present disclosure, additional embodiments may be used that are compatible with the present disclosure. As examples only, when the preceding description shows one or more axially displaced sets or neutron detection means and a greater number of offsets may be selected to improve the resolution of the medium. One or more detection methods facing the mud channel and protecting it from neutrons entering from the hole may be considered to improve environmental corrections. Additionally, in other embodiments, if a neutron generator and/or neutron gamma-ray detectors are used, it may be mounted on each side of the generator. In addition, there are pairs of detectors (thermal and epithermal) that can be used at all or some azimuthal locations.

Although specific embodiments of the foregoing invention have been described in detail, this description has been prepared for illustrative purposes only. Many modifications of the equivalent steps corresponding to the features disclosed can be made in illustrative embodiments, and in addition to the embodiments described above, a person skilled in the art may, without departing from the substance and scope of the invention specified in the following claims, make embodiments Other, these models fall within the field of general interpretation, so that the field includes those modifications and their corresponding structures.