Method and device for measuring radial detection depth of near-bit azimuth gamma while-drilling tool

Abstract

The invention discloses a measuring method and device for the radial detection depth of a near-bit azimuth gamma tool while drilling. The measuring method comprises the steps that an azimuth gamma receiving short section is arranged around an azimuth gamma transmitting short section; according to the outer diameter of the azimuth gamma emission nipple, a gamma source rock core with the radiation intensity matched with the inner diameter is selected; the gamma source core is arranged outside the azimuth gamma emission short section in a sleeving mode; testing the gamma counting rate of the near-bit azimuth gamma while-drilling tool; increasing the radial width of the gamma source rock core, and testing the gamma counting rate; when the gamma source core is increased from a target radial width and the gamma counting rate cannot be increased, the target radial width is the radial detection depth of the near-bit azimuth gamma while-drilling tool under a radiation intensity; the gamma source cores with different radiation intensities are replaced, and radial detection depths under different radiation intensities are measured. According to the method, the intuition and the reliability of a measurement result are improved, so that field geosteering and well track adjustment can be guided and supported more accurately.

Description

Technical Field

[0001] The present invention relates to the technical field of measurement-while-drilling in oil and gas drilling, and in particular, to a method and device for measuring the radial detection depth of a near-bit azimuth gamma measurement-while-drilling tool. Background Art

[0002] The near-bit azimuth gamma measurement-while-drilling technology is a new type of geological steering measurement-while-drilling technology developed in recent years. Compared with the conventional natural gamma measurement technology, it can not only distinguish the lithologies of the formations on both sides of the formation interface, but also accurately determine the relative position relationship of the formations on both sides of the interface, and has obvious effects in improving the reservoir encounter rate and drilling efficiency, optimizing the wellbore trajectory, reducing the downhole geological risks, etc. With the exploration and development of complex reservoir oil and gas resources and unconventional resources such as shale oil and gas and tight oil and gas, it has broad application prospects.

[0003] The radial detection depth (i.e., the maximum detection distance in the radial direction) of the near-bit azimuth gamma measurement-while-drilling tool is one of the important technical indicators characterizing its measurement performance, and has important influences on the formation lithology identification ability of the tool, the azimuth gamma measurement accuracy, the judgment of the relative position between the bit and the formation interface, the adjustment of the wellbore trajectory, etc. At present, the near-bit azimuth gamma measurement-while-drilling tool is generally in the stage of research and experimental application. Although individual manufacturers already have the development ability, there are problems such as less R & D experience, small on-site application scale, and lack of corresponding equipment, methods, standards, etc. for tool performance testing. Specifically in terms of the measurement of the radial detection depth of the near-bit azimuth gamma measurement-while-drilling tool, there is currently a lack of corresponding measurement devices and methods. It mainly relies on the Monte Carlo theory and uses software such as MNCP and GEANT to simulate and calculate the radial detection depth of the near-bit azimuth gamma measurement-while-drilling tool. There are problems such as strong software professionalism and difficulty in mastering, large influence of the calculation results on the modeling method and parameter setting, large difference between the simulated calculation depth and the on-site actual situation, and inability to accurately know the actual detection depth of the tool. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and device for measuring the radial detection depth of a near-bit azimuth gamma measurement-while-drilling tool, so as to solve the technical problems that the method of currently simulating and calculating the radial detection depth of the near-bit azimuth gamma measurement-while-drilling tool based on complex software is difficult to master, and the calculation results are easily affected by the modeling method and parameter setting, resulting in large errors.

[0005] The above object of the present invention can be achieved by the following technical solutions:

[0006] The present invention provides a method for measuring the radial detection depth of a near-bit azimuth gamma measurement-while-drilling tool. The near-bit azimuth gamma measurement-while-drilling tool includes an azimuth gamma emission sub and an azimuth gamma reception sub. The measurement method includes:

[0007] Place the azimuth gamma receiving sub around the azimuth gamma transmitting sub;

[0008] According to the outer diameter of the azimuth gamma transmitting sub, select a gamma source core with a matching inner diameter and a certain radiation intensity; sleeve the gamma source core outside the azimuth gamma transmitting sub; test the gamma count rate of the near-bit azimuth gamma logging-while-drilling tool; increase the outer diameter of the gamma source core to increase the radial width of the gamma source core, and test the gamma count rate of the near-bit azimuth gamma logging-while-drilling tool in the same way as above; until the gamma count rate cannot increase when the gamma source core increases from a target radial width, the target radial width is the radial detection depth of the near-bit azimuth gamma logging-while-drilling tool at a certain radiation intensity; replace the gamma source core with a matching inner diameter and a different radiation intensity, and measure the radial detection depths of the near-bit azimuth gamma logging-while-drilling tool at different radiation intensities in the same way as above.

[0009] In an embodiment of the present invention, placing the azimuth gamma receiving sub around the azimuth gamma transmitting sub includes: horizontally placing the azimuth gamma transmitting sub, and horizontally placing the azimuth gamma receiving sub on the side of the azimuth gamma transmitting sub; wherein, the distance between the azimuth gamma receiving sub and the azimuth gamma transmitting sub is 2 m to 15 m.

[0010] In an embodiment of the present invention, the gamma source core includes a gamma source base core and multiple gamma source centering cores. The step of sleeving the gamma source core outside the azimuth gamma transmitting sub includes the following steps: sleeving the gamma source base core outside the azimuth gamma transmitting sub; or sleeving the gamma source base core outside the azimuth gamma transmitting sub, and then successively sleeving at least one of the gamma source centering cores outside the gamma source base core from the inside to the outside.

[0011] In an embodiment of the present invention, increasing the outer diameter of the gamma source core to increase the radial width of the gamma source core includes: successively sleeving at least one other gamma source centering core outside the gamma source base core or the outermost gamma source centering core from the inside to the outside to gradually increase the outer diameter of the gamma source core.

[0012] In an embodiment of the present invention, the step of sleeving the gamma source core outside the azimuth gamma transmitting sub further includes: adjusting the gamma source core to be coaxial with the azimuth gamma transmitting sub, and the center of the gamma source core is located at the position of the gamma probe of the azimuth gamma transmitting sub.

[0013] In an embodiment of the present invention, the method for testing the gamma count rate of the near-bit azimuth gamma logging-while-drilling tool includes the following steps: the azimuth gamma emission sub-section remains stationary within the gamma source core, and the gamma count rate of the near-bit azimuth gamma logging-while-drilling tool in the stationary state is tested; the azimuth gamma emission sub-section rotates within the gamma source core, and the gamma count rate of the near-bit azimuth gamma logging-while-drilling tool in the rotating state is tested.

[0014] In an embodiment of the present invention, the gamma count rate is the average value of the gamma count rates tested by the near-bit azimuth gamma logging-while-drilling tool within a single test time, where the single test time is greater than or equal to 15 min.

[0015] The present invention also provides a measuring device for the radial detection depth of a near-bit azimuth gamma logging-while-drilling tool. Using the above measuring method, the measuring device includes: a rotating mechanism for installing the azimuth gamma emission sub-section of the near-bit azimuth gamma logging-while-drilling tool and capable of driving the azimuth gamma emission sub-section to rotate; a gamma source core structure including a plurality of gamma source core components with different radiation intensities, and each of the gamma source core components includes a plurality of gamma source cores with the same inner diameter and different outer diameters, and the inner diameter of the gamma source core is matched with the outer diameter of the azimuth gamma emission sub-section and can be sleeved outside the azimuth gamma emission sub-section; a gamma source core installation mechanism for installing one of the gamma source cores.

[0016] In an embodiment of the present invention, each of the gamma source cores includes a gamma source base core with the same radiation intensity and a plurality of gamma source concentrators. The inner diameter of the gamma source base core of each of the gamma source cores is matched with the outer diameter of the azimuth gamma emission sub-section and can be sleeved outside the azimuth gamma emission sub-section. The plurality of gamma source concentrators of each of the gamma source cores can be successively sleeved outside the corresponding gamma source base core from the inside out to increase the outer diameter of the gamma source core.

[0017] In an embodiment of the present invention, the gamma source core structure includes a plurality of gamma source concentrator assemblies and a plurality of gamma source base core assemblies. The radiation intensities of the plurality of gamma source concentrator assemblies are different. Each of the gamma source concentrator assemblies includes a plurality of gamma source concentrators with inner diameters increasing from small to large and capable of being successively sleeved from the inside out; each of the gamma source base core assemblies includes a plurality of gamma source base cores with the same inner diameter and different radiation intensities. The inner diameters of the gamma source base cores of the plurality of gamma source base core assemblies are different, and the outer diameter of the gamma source base core of each of the gamma source base core assemblies can be matched with the inner diameter of one of the gamma source concentrators of the gamma source concentrator assembly with the same radiation intensity, so that each of the gamma source base core assemblies can be assembled with at least one of the gamma source concentrators of the plurality of gamma source concentrator assemblies into a plurality of gamma source core components.

[0018] In an embodiment of the present invention, the gamma source base center and the gamma source adjustment center are both ring-shaped, the gamma source base center includes an upper half ring substrate and a lower half ring substrate, the upper half ring substrate and the lower half ring substrate are butt-jointed to form the gamma source base center, the gamma source adjustment center includes an upper half ring adjustment sheet and a lower half ring adjustment sheet, the upper half ring adjustment sheet and the lower half ring adjustment sheet are butt-jointed to form the gamma source adjustment center.

[0019] In an embodiment of the present invention, the measuring device also includes a test bench, the rotating mechanism is mounted on the test bench, the azimuth gamma emission short section is installed on the rotating mechanism along a horizontal direction, the gamma source core installation mechanism includes a horizontal adjustment mechanism, a lifting adjustment structure and a core clamping structure, the horizontal adjustment structure can be movably arranged on the test bench along the horizontal direction, the lifting adjustment structure can be movably arranged on the horizontal adjustment structure along the vertical direction, and the core clamping structure is installed on the lifting adjustment structure.

[0020] In an embodiment of the present invention, the core clamping structure includes a core disk, a core cover and a plurality of connecting parts. The core disk is installed on the lifting and adjusting structure. The core cover is connected to the core disk through a plurality of the connecting parts. A clamping space for clamping and fixing the gamma source core is formed between the core cover and the core disk.

[0021] In an embodiment of the present invention, the horizontal adjustment structure includes a lead screw, a lead screw seat, a sliding base and a sliding fitting structure. The sliding base is slidingly fitted on the test bench along the horizontal direction through the sliding fitting structure. The lead screw seat is fixed on the test bench. One end of the lead screw passes through the lead screw seat and is rotatably connected to the sliding seat, and the lead screw is threadedly fitted to the lead screw seat.

[0022] In an embodiment of the present invention, the rotating mechanism includes a motor, a transmission structure, a first core shaft, a second core shaft, a first adapter structure and a second adapter structure, the two ends of the azimuth gamma transmitting short section are connected to the first core shaft and the second core shaft, the first core shaft is rotatably mounted on the test bench through the first adapter structure, the second core shaft is rotatably mounted on the test bench through the second adapter structure, the rotating shaft of the motor is connected to the first core shaft through the transmission structure and can drive the first core shaft to rotate through the transmission structure.

[0023] The characteristics and advantages of the present invention are:

[0024] The measuring method for the radial detection depth of the near-bit azimuth gamma logging-while-drilling tool of the present invention not only makes up for the disadvantages of large error and strong professionalism in current software simulation calculations, but also improves the intuitiveness and reliability of the measurement results, so as to more accurately guide and support on-site geological steering and wellbore trajectory adjustment.

[0025] The measuring device for the radial detection depth of the near-bit azimuth gamma logging-while-drilling tool of the present invention installs multiple gamma source cores with the same inner cavity but different outer diameters on the gamma source core installation mechanism one by one and slews them outside the gamma source emitting sub-section. The azimuth gamma emitting sub-section is driven to rotate inside the gamma source core by the rotating mechanism, so that the radial detection depth of the near-bit azimuth gamma logging-while-drilling tool under different radiation intensities in the rotating state (i.e., the working state of the near-bit azimuth gamma logging-while-drilling tool) can be measured by using the test method of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0027] Figure 1 It is a schematic flow chart of the measuring method of the present invention.

[0028] Figure 2 It is a side view during the test of the test device of the present invention.

[0029] Figure 3 It is a usage state diagram of the core clamping mechanism of the present invention.

[0030] Figure 4 It is a top view during the test of the test device of the present invention.

[0031] Figure 5 It is a side view before the test of the test device of the present invention.

[0032] Figure 6 It is a top view before the test of the test device of the present invention.

[0033] Figure 7 It is an end face schematic diagram of the gamma source core of the present invention.

[0034] Figure 8 It is a side view schematic diagram of the gamma source core of the present invention.

[0035] Figure 9 It is an end face schematic diagram of the gamma source centering of the present invention.

[0036] Figure 10Side schematic diagram of centering the gamma source of the present invention.

[0037] Figure 11 Installation schematic diagram of the gamma source core of the present invention.

[0038] In the figure:

[0039] 11. Azimuth gamma emission sub-section; 12. Azimuth gamma reception sub-section; 13. Probe identification structure; 14. Computer;

[0040] 2. Gamma source core; 21. Gamma source base core; 211. Upper half-ring substrate; 212. Lower half-ring substrate; 22. Gamma source centering; 221. Upper half-ring adjusting piece; 222. Lower half-ring adjusting piece;

[0041] 3. Rotating mechanism; 31. Motor; 32. Transmission structure; 33. First core shaft; 34. Second core shaft; 35. First adapter structure; 36. Second adapter structure; 37. Male connector; 38. Female connector; 39. Length adjusting rod;

[0042] 4. Gamma source core installation mechanism; 41. Core clamping structure; 411. Core plate; 412. Core cover; 413. Connector; 42. Horizontal adjusting structure; 421. Lead screw; 422. Lead screw seat; 423. Sliding base; 424. Sliding fit structure; 425. Handwheel; 43. Lifting adjusting structure;

[0043] 5. Test bench; 51. Lower platform; 52. Upper platform; 53. Support column; 54. Hollow groove. Specific implementation mode

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0045] Embodiment 1

[0046] As Figure 1 , Figure 2 , Figure 3 And Figure 4 shown, the present invention provides a method for measuring the radial detection depth of a near-bit azimuth gamma logging-while-drilling tool. The near-bit azimuth gamma logging-while-drilling tool includes an azimuth gamma emission sub-section 11 and an azimuth gamma reception sub-section 12. The measurement method includes:

[0047] Step S1: Place the azimuth gamma receiving sub 12 around the azimuth gamma transmitting sub 11. It should be noted that the order of this step is not specifically limited, as long as it is completed before the test.

[0048] Specifically, the azimuth gamma transmitting sub 11 can be placed horizontally, and the azimuth gamma receiving sub 12 can be placed horizontally on the side of the azimuth gamma transmitting sub 11; among them, the distance between the azimuth gamma receiving sub 12 and the azimuth gamma transmitting sub 11 is less than the receiving distance of the azimuth gamma, preferably 2 m to 15 m. The azimuth gamma transmitting sub 11 and the azimuth gamma receiving sub 12 are wirelessly communicatively connected. The azimuth gamma receiving sub 12 can be connected to a data line through a data reading port, and then electrically connected to a computer 14 with test software through the data line, so as to realize data transmission. A gamma probe is provided in the azimuth gamma transmitting sub 11 for detecting gamma data, and then transmitting the gamma data to the azimuth gamma receiving sub 12. The gamma data is transmitted to the computer 14 through the azimuth gamma receiving sub 12, and then the computer 14 analyzes and processes the gamma data through the test software.

[0049] Among them, when the near-bit azimuth gamma while-drilling tool is actually used, the front end of the azimuth gamma transmitting sub 11 is connected to the drill bit, the rear end of the azimuth gamma transmitting sub 11 is connected to a centralizer through a screw, the centralizer is connected to the azimuth gamma receiving sub 12 through a drill string backpressure valve, the rear end of the azimuth gamma receiving sub 12 is connected to a non-magnetic drill collar, and the non-magnetic drill collar is wirelessly communicatively connected to a measurement while drilling (MWD), so as to realize the measurement while drilling near the drill bit of the near-bit azimuth gamma while-drilling tool. The more specific structures of the azimuth gamma receiving sub 12 and the azimuth gamma transmitting sub 11 are the same as those of the prior art, and will not be elaborated here.

[0050] Step S2: Select a gamma source core 2 with a radioactive intensity and an inner diameter matching the outer diameter of the azimuth gamma transmitting sub 11.

[0051] Specifically, the gamma source core 2 is a core structure with natural radioactive elements (i.e., gamma ray particles), which can be detected by the gamma probe in the azimuth gamma transmitting sub 11. The gamma source core 2 is generally a cylindrical structure, and its inner diameter matches the outer diameter of the azimuth gamma transmitting sub 11, that is, the inner diameter of the gamma source core 2 is equal to the wellbore size matching the near-bit azimuth gamma while-drilling tool, that is, the gamma source core 2 is equivalent to being able to simulate the formation around the wellbore.

[0052] Step S3: Sleeve the gamma source core 2 outside the azimuth gamma transmitting sub 11.

[0053] Specifically, the inner diameter of the gamma source core 2 is slightly larger than the outer diameter of the azimuth gamma emission sub - section 11, such that there is a clearance fit between the gamma source core 2 and the azimuth gamma emission sub - section 11. Therefore, the azimuth gamma emission sub - section 11 can rotate within the gamma source core 2.

[0054] Step S4: Test the gamma count rate of the near - bit azimuth gamma logging - while - drilling tool.

[0055] Specifically, the azimuth gamma emission sub - section 11 detects the gamma data of the gamma source core 2, and then transmits the gamma data to the azimuth gamma receiving sub - section 12. The azimuth gamma receiving sub - section 12 transmits the gamma data to the computer 14. Then, the computer 14 analyzes and processes the gamma data through the test software to generate the gamma count rate.

[0056] Step S5: Increase the outer diameter of the gamma source core 2 to increase the radial width of the gamma source core 2, and test the gamma count rate of the near - bit azimuth gamma logging - while - drilling tool in the same manner as above. Wherein, testing the gamma count rate in the same manner as above means repeating the above - mentioned Step S3 and Step S4.

[0057] Specifically, in some embodiments of the present invention, the gamma source core 2 is a core structure formed by sleeving multiple cores from the inside to the outside, and the outer diameter of the gamma source core 2 can be changed by disassembly and assembly. In other embodiments of the present invention, the gamma source core 2 is an integrally formed core structure. By preparing multiple gamma source cores 2 with the same inner diameter but different outer diameters, the gamma source core 2 with a different outer diameter can be directly replaced for testing.

[0058] Step S6: Until the gamma count rate cannot increase when the radial width of the gamma source core 2 is increased from a target radial width, where the target radial width is the radial detection depth of the near - bit azimuth gamma logging - while - drilling tool at a certain radiation intensity.

[0059] Specifically, when the outer diameter of the gamma source core 2 is increased to increase the radial width of the gamma source core 2, and the gamma count rate measured by the near - bit azimuth gamma logging - while - drilling tool does not increase, it indicates that the radial measurement depth of the near - bit azimuth gamma logging - while - drilling tool is less than the increased radial width of the gamma source core 2. Therefore, when the gamma source core 2 is increased from a target radial width and the gamma count rate measured by the near - bit azimuth gamma logging - while - drilling tool does not increase, it means that the target radial width is the radial detection depth of the near - bit azimuth gamma logging - while - drilling tool at the radiation intensity of the gamma source core 2, that is, the maximum detection distance in the radial direction.

[0060] Step S7: Replace the gamma source core 2 with different radiation intensities and a matching inner diameter, and measure the radial detection depths of the near - bit azimuth gamma logging - while - drilling tool at different radiation intensities in the same manner as above. Wherein, measuring the radial detection depths at different radiation intensities in the same manner as above means repeating the above - mentioned Steps S2 to S6.

[0061] The measuring method for the radial detection depth of the near-bit azimuth gamma logging-while-drilling tool of the present invention not only makes up for the disadvantages of large error and strong professionalism in current software simulation calculations, but also improves the intuitiveness and reliability of the measurement results, so as to more accurately guide and support on-site geological steering and wellbore trajectory adjustment. Among them, technicians can analyze by combining the azimuth gamma curve measured by the near-bit azimuth gamma logging-while-drilling tool during the drilling process with the radial detection depth of the near-bit azimuth gamma logging-while-drilling tool of the present invention under different radiation intensities, so as to more accurately judge the distance between the near-bit azimuth gamma logging-while-drilling tool and the formation interface, and further can more accurately guide and support on-site geological steering and wellbore trajectory adjustment.

[0062] As Figure 3 shown, in the embodiment of the present invention, the gamma source core 2 includes a gamma source base core 21 and a plurality of gamma source centering cores 22. Among them, the inner diameter of the gamma source base core 21 matches the outer diameter of the azimuth gamma emission sub 11, and the plurality of gamma source centering cores 22 can be successively sleeved on the gamma source base core 21 from the inside to the outside. Therefore, by disassembling and assembling the plurality of gamma source centering cores 22, the gamma source core 2 can have different outer diameters, that is, different radial widths.

[0063] Specifically, in step S3, sleeving the gamma source core 2 outside the azimuth gamma emission sub 11 includes the following steps: sleeving the gamma source base core 21 outside the azimuth gamma emission sub 11; or sleeving the gamma source base core 21 outside the azimuth gamma emission sub 11, and then successively sleeving at least one gamma source centering core 22 outside the gamma source base core 21 from the inside to the outside. In step S5, increasing the outer diameter of the gamma source core 2 and thus increasing the radial width of the gamma source core 2 includes: successively sleeving at least another gamma source centering core 22 outside the gamma source base core 21 or the outermost gamma source centering core 22 from the inside to the outside, so as to gradually increase the outer diameter of the gamma source core 2.

[0064] As Figure 3As shown, in the embodiments of the present invention, the minimum radial detection depth of the near-bit azimuth gamma logging-while-drilling tool can be roughly estimated based on experience, and thus the initial outer diameter of the gamma source core 2 can be selected. That is, the initial outer diameter of the gamma source core 2 can be slightly larger than the estimated minimum radial detection depth. If the gamma source base core 21 is larger than the initial outer diameter of the gamma source core 2, it is selected to first conduct the first test of the gamma counting rate with the gamma source base core 21 alone as the gamma source core 2, and then successively sleeve multiple gamma source alignment cores 22 on the gamma source base core 21 to increase the outer diameter of the gamma source core 2 step by step and conduct tests; if the gamma source base core 21 is smaller than the initial outer diameter of the gamma source core 2, it is selected to sleeve at least one gamma source alignment core 22 on the gamma source base core 21 as the gamma source core 2 to conduct the first test of the gamma counting rate, and then continue to sleeve gamma source alignment cores 22 with larger outer diameters on the gamma source alignment cores 22 with smaller outer diameters to increase the outer diameter of the gamma source core 2 step by step and conduct tests.

[0065] As Figure 3 shown, in the embodiments of the present invention, in step S3, when sleeving the gamma source core 2 on the azimuth gamma emission sub-section 11, it further includes: adjusting the gamma source core 2 to be coaxial with the azimuth gamma emission sub-section 11, and the center of the gamma source core 2 (i.e., the midpoint of its axis) is located at the position of the gamma probe of the azimuth gamma emission sub-section 11.

[0066] Specifically, as Figure 6 shown, on the outer peripheral surface of the azimuth gamma emission sub-section 11 at the position of its gamma probe, a probe identification structure 13 is provided. By adjusting the center of the gamma source core 2 to coincide with this probe identification structure 13, the gamma probe of the azimuth gamma emission sub-section 11 can detect gamma rays of the gamma source core 2 at the center of the gamma source core 2.

[0067] As Figure 3 shown, in the embodiments of the present invention, when testing the gamma counting rate of the near-bit azimuth gamma logging-while-drilling tool, it includes: the azimuth gamma emission sub-section 11 rotates within the gamma source core 2 to test the gamma counting rate of the near-bit azimuth gamma logging-while-drilling tool in the rotating state. According to the gamma counting rate in the rotating state, the radial detection depth corresponding to different radiation intensities of the near-bit azimuth gamma logging-while-drilling tool in the rotating state can be measured, and thus the radial detection ability of the near-bit azimuth gamma logging-while-drilling tool under the working state can be more accurately reflected.

[0068] Of course, when testing the gamma counting rate of the near-bit azimuth gamma logging-while-drilling tool, it can also include: the azimuth gamma emission sub-section 11 remains stationary within the gamma source core 2 to test the gamma counting rate of the near-bit azimuth gamma logging-while-drilling tool in the stationary state. By comparing and analyzing the gamma counting rate in the stationary state and the gamma counting rate in the rotating state, the influence of rotation on the radial detection ability of the near-bit azimuth gamma logging-while-drilling tool can be analyzed.

[0069] Specifically, the gamma counting rate is the average value of the gamma counting rates measured by the azimuth gamma emission sub 11 within a single test time, where the single test time is greater than or equal to 15 min. In this embodiment, the gamma counting rate in the stationary state is first measured, and then the rotation speed of the azimuth gamma emission sub 11 is gradually increased. For example, the rotation speed range is 0 - 500 rpm, and the rotation speed can be gradually increased to 500 rpm, with each speed adjustment less than 100 rpm.

[0070] Embodiment 2

[0071] To better implement the measurement method of the present invention, the present invention also provides a measurement device for the radial detection depth of a near-bit azimuth gamma while-drilling tool.

[0072] As Figures 2 to 6 shown, the measurement device includes: a rotating mechanism 3 for installing the azimuth gamma emission sub 11 of the near-bit azimuth gamma while-drilling tool and capable of driving the azimuth gamma emission sub 11 to rotate; a gamma source core structure including a plurality of gamma source core components with different radiation intensities, and each gamma source core component includes a plurality of gamma source cores 2 with the same inner diameter and different outer diameters, and the inner diameter of the gamma source core 2 matches the outer diameter of the azimuth gamma emission sub 11 and can be sleeved outside the azimuth gamma emission sub 11; a gamma source core installation mechanism 4 for installing one of the gamma source cores 2.

[0073] For the measurement device of the radial detection depth of the near-bit azimuth gamma while-drilling tool of the present invention, by successively installing a plurality of gamma source cores 2 with the same inner cavity and different outer diameters on the gamma source core installation mechanism 4 and sleeving them outside the azimuth gamma emission sub 11, and driving the azimuth gamma emission sub 11 to rotate within the gamma source core 2 by the rotating mechanism 3, the radial detection depth of the near-bit azimuth gamma while-drilling tool under different radiation intensities in the rotating state can be measured by using the test method of the present invention.

[0074] As Figure 3 shown, in the embodiment of the present invention, each gamma source core 2 includes a gamma source base core 21 with the same radiation intensity and a plurality of gamma source centering cores 22. The inner diameter of the gamma source base core 21 of each gamma source core 2 matches the outer diameter of the azimuth gamma emission sub 11 and can be sleeved outside the azimuth gamma emission sub 11. The plurality of gamma source centering cores 22 of each gamma source core 2 can be successively sleeved outside the corresponding gamma source base core 21 from the inside out to increase the outer diameter of the gamma source core 2. That is, a plurality of gamma source cores 2 of a gamma source component include a gamma source base core 21 that can be used alone as a radial width of a gamma source core 2, or can include a gamma source base core 21 with the same radiation intensity and a plurality of gamma source centering cores 22 to be assembled into a plurality of gamma source cores 2 with different radial widths.

[0075] Combined Figure 3 As shown, in order to improve the applicability of the test device of the present invention, the gamma source core structure includes a plurality of gamma source centering components and a plurality of gamma source base core components. The radiation intensities of the plurality of gamma source centering components are different. Each gamma source centering component includes a plurality of gamma source centering members 22 with inner diameters increasing from small to large and sleeved one by one from the inside to the outside, that is, the inner diameter of the latter gamma source centering member 22 is equal to the outer diameter of the previous gamma source centering member 22; each gamma source base core component includes a plurality of gamma source base cores 21 with the same inner diameter and different radiation intensities. The inner diameters of the gamma source base cores 21 of the plurality of gamma source base core components are different, and the outer diameter of each gamma source base core 21 of each gamma source base core component can match the inner diameter of one of the gamma source centering members 22 of the gamma source centering component with the same radiation intensity, that is, the outer diameter of any gamma source base core 21 can be equal to the inner diameter of one of the gamma source centering members 22, so that each gamma source base core component can be assembled with at least one gamma source centering member 22 of the plurality of gamma source centering components into a plurality of gamma source core components.

[0076] By providing a plurality of gamma source centering components and a plurality of gamma source base core components, a plurality of gamma source base cores 21 with the same inner diameter and different radiation intensities can be respectively assembled with gamma source centering members 22 with matching sizes corresponding to the radiation intensities into a plurality of gamma source core components that can match the outer diameter of a near-bit azimuth gamma while-drilling tool. Moreover, a plurality of gamma source base cores 21 with different inner diameters can be assembled with gamma source centering members 22 with matching sizes into a plurality of gamma source core components that can match near-bit azimuth gamma while-drilling tools with different outer diameters. Thus, according to the outer diameter of the near-bit azimuth gamma while-drilling tool to be tested, a gamma source base core 21 with a matching inner diameter and a radiation intensity is selected and assembled with a gamma source centering member 22 with a matching inner diameter and the same radiation intensity to form a gamma source core 2, and then the gamma source core 2 is sleeved outside the azimuth gamma emission sub 11 for testing.

[0077] To facilitate the disassembly and assembly of the gamma source base core 21 and the gamma source centering member 22, as Figure 7 and Figure 8 shown, both the gamma source base core 21 and the gamma source centering member 22 are in a ring shape. The gamma source base core 21 includes an upper half-ring substrate 211 and a lower half-ring substrate 212, and the upper half-ring substrate 211 and the lower half-ring substrate 212 are butted to form the gamma source base core 21. As Figure 7 and Figure 8 shown, the gamma source centering member 22 includes an upper half-ring adjusting piece 221 and a lower half-ring adjusting piece 222, and the upper half-ring adjusting piece 221 and the lower half-ring adjusting piece 222 are butted to form the gamma source centering member 22.

[0078] Combined Figures 7 to 10As shown, in the embodiments of the present invention, the gamma source core structure includes three gamma source centering components corresponding to three radiation intensities. The radial width and number of gamma source centering 22 in each gamma source centering component are not specifically limited and can be set according to the measurement accuracy requirements. The higher the measurement accuracy requirements, the smaller the radial width of gamma source centering 22, and vice versa. The gamma source core structure includes four gamma source base core components corresponding to near-bit azimuth gamma logging-while-drilling tools with four outer diameters. Each gamma source base core component includes three gamma source base cores 21 with the same inner diameter and corresponding to three radiation intensities. Therefore, the three gamma source base cores 21 of each gamma source base core component can be assembled with the gamma source centering 22 of the three gamma source centering components to form three gamma source core components capable of testing a near-bit azimuth gamma logging-while-drilling tool with a certain outer diameter. Using these three gamma source core components, the radial measurement depth of a near-bit azimuth gamma logging-while-drilling tool with a certain outer diameter under three radiation intensities can be tested.

[0079] Specifically, the three radiation intensities are low radiation intensity (nominal value and uncertainty are 24.6 API ± 0.6 API), medium radiation intensity (nominal value and uncertainty are 223.0 API ± 4.4 API), and high radiation intensity (nominal value and uncertainty are 342.7 API ± 6.7 API). The sizes of the multiple gamma source centering 22 of the three gamma source centering components are the same. The inner diameters r1 from small to large are 215.9 mm, 225.9 mm, 235.9 mm,..., 495.9 mm, and the outer diameters R1 from small to large are 225.9 mm, 235.9 mm, 245.9 mm,..., 505.9 mm, and the length L1 is 500 mm for all. The length L of the gamma source base core 21 in the four gamma source base core components is also 500 mm for all; the inner diameter r of the gamma source base core 21 with three radiation intensities in the first gamma source base core component is 118 mm, and the outer diameter R is 215.9 mm; the inner diameter r of the gamma source base core 21 with three radiation intensities in the second gamma source base core component is 152.4 mm, and the outer diameter R is 255.9 mm; the inner diameter r of the gamma source base core 21 with three radiation intensities in the third gamma source base core component is 215.9 mm, and the outer diameter R is 315.9 mm; the inner diameter r of the gamma source base core 21 with three radiation intensities in the fourth gamma source base core component is 311.2 mm, and the outer diameter R is 415.9 mm. Therefore, through assembly, it can be applicable to near-bit azimuth gamma logging-while-drilling tools matching wellbore sizes such as 3.75 〃 、4.75 〃 、6.75 〃 etc.

[0080] Such as Figure 2 、 Figure 4 And Figure 5 And Figure 6As shown, in an embodiment of the present invention, the measuring device also includes a test bench 5, a rotating mechanism 3 is mounted on the test bench 5, an azimuth gamma emission short section 11 is installed on the rotating mechanism 3 along a horizontal direction, and a gamma source core installation mechanism 4 includes a horizontal adjustment structure 42, a lifting adjustment structure 43 and a core clamping structure 41, the horizontal adjustment structure 42 can be movably arranged on the test bench 5 along the horizontal direction, the lifting adjustment structure 43 can be movably arranged on the horizontal adjustment structure 42 along the vertical direction, and the core clamping structure 41 is installed on the lifting adjustment structure 43. The lifting and lowering adjustment structure 43 is driven to move in the horizontal direction by the horizontal adjustment structure 42, so that the core clamping structure 41 moves synchronously with the lifting and lowering adjustment structure 43 to adjust the center of the core clamping structure 41 to coincide with the gamma probe of the azimuth gamma emitting short section 11 in a vertical direction, and the core clamping structure 41 is driven to move in the vertical direction by the lifting and lowering adjustment structure 43 to adjust the center of the core clamping structure 41 to coincide with the center of the azimuth gamma emitting short section 11, so that after the core clamping structure 41 clamps and fixes the gamma source core 2, the gamma source core 2 is coaxial with the azimuth gamma emitting short section 11, and the gamma probe of the azimuth gamma emitting short section 11 is located at the center of the gamma source core 2.

[0081] Specifically, Figure 2 As shown, the rotating mechanism 3 includes a motor 31, a transmission structure 32, a first mandrel 33, a second mandrel 34, a first adapter structure 35 and a second adapter structure 36. Both ends of the azimuth gamma emission short section 11 are connected to the first mandrel 33 and the second mandrel 34. The first mandrel 33 is rotatably mounted on the test bench 5 through the first adapter structure 35. The second mandrel 34 is rotatably mounted on the test bench 5 through the second adapter structure 36. The rotating shaft of the motor 31 is connected to the first mandrel 33 through the transmission structure 32 and can drive the first mandrel 33 to rotate through the transmission structure 32. The azimuth gamma test short section rotates synchronously driven by the first mandrel 33.

[0082] Among them, Figure 2As shown, the transmission structure 32 includes a driving wheel mounted on the rotating shaft of the motor 31, a driven wheel mounted on the first mandrel 33, and a transmission belt connecting the driving wheel and the driven wheel; the first adapter structure 35 includes a first bearing seat mounted on the test platform and a ball bearing mounted on the first bearing seat and rotatably connected to the first mandrel 33; the second adapter structure 36 includes a second bearing seat mounted on the test platform and a spherical roller bearing mounted on the second bearing seat and rotatably connected to the second mandrel 34. The first mandrel 33 can be connected to one end of the azimuth gamma emission sub-section 11 through a male connector 37. The other end of the azimuth gamma emission sub-section 11 is connected to a female connector 38, and the female connector 38 can be connected to the second mandrel 34 through a length adjustment rod 39. The second mandrel 34 is axially provided with a length adjustment hole (i.e., the length direction of the azimuth gamma emission sub-section 11) matching the length adjustment rod 39 to adjust the depth of the length adjustment rod 39 inserted into the length adjustment hole according to the length of different azimuth gamma emission sub-sections 11, thereby improving the applicability of the test device of the present invention.

[0083] As Figure 2 and Figure 5 shown, the horizontal adjustment structure 42 includes a lead screw 421, a lead screw seat 422, a sliding base 423, and a sliding fit structure 424. The sliding base 423 is slidably disposed on the test bench 5 in the horizontal direction through the sliding fit structure 424. The lead screw seat 422 is fixed to the test bench 5. The first end of the lead screw 421 passes through the lead screw seat 422 and is rotatably connected to the sliding seat, and the lead screw 421 is in threaded connection with the lead screw seat 422. The second end of the lead screw 421 is provided with a handwheel 425. Since the lead screw seat 422 is fixed and the sliding base 423 is limited by the sliding fit structure 424, by holding the handwheel 425 and rotating the lead screw 421, the rotation of the lead screw 421 can be converted into a linear motion of the sliding base 423 in the horizontal direction. In addition, the lifting adjustment structure 43 can be a lifting lead screw, an electric lifting rod, a lifting cylinder, a lifting oil cylinder, or other lifting driving members mounted on the sliding base 423.

[0084] Specifically, the test bench 5 includes an upper platform 52 and a lower platform 51. The lower platform 51 is erected above the upper platform 52 through a plurality of support columns 53. The rotating mechanism 3 is mounted on the upper platform 52, and the horizontal adjustment mechanism is mounted on the lower platform 51. The upper platform 52 is provided with a hollow groove 54, so that the core clamping structure 41 can rise from the hollow groove 54 to make the center of the core clamping structure 41 coincide with the center of the azimuth gamma emission sub-section 11. The sliding fit structure 424 includes a plurality of sliding rails extending in the horizontal direction and arranged in parallel and a plurality of sliding grooves slidably engaged with the plurality of sliding rails. One of the sliding rails and the sliding grooves is provided on the sliding base 423, and the other is provided on the lower platform 51.

[0085] As Figure 3As shown, in the embodiments of the present invention, the core clamping structure 41 includes a core plate 411, a core cover 412, and a plurality of connecting members 413. The core plate 411 is installed on the lifting and adjusting structure 43. The core cover 412 is connected to the core plate 411 through a plurality of connecting members 413. A clamping space for clamping and fixing the gamma source core 2 is formed between the core cover 412 and the core plate 411.

[0086] Specifically, the center of the core clamping structure 41, that is, the center of the clamping space. The inner sides of the core plate 411 and the core cover 412 are provided with grooves generally in a V shape, which cooperate to form a clamping space after docking. The connecting member 413 can be a bolt or other fasteners. As Figure 3 and Figure 11 shown, when it is necessary to disassemble and assemble the gamma source core 2, first remove the core cover 412, then place the gamma source core 2 on the core plate 411, and then connect the core cover 412 to the core plate 411 through the connecting member 413 and press and fix the gamma source core 2. During installation, first place the lower half-ring base piece 212 of the gamma source base core 21 and the lower half-ring adjusting piece 222 of the gamma source centering 22 on the core plate 411 in cooperation, and then adjust through the cooperation of the horizontal adjusting structure 42 and the lifting and adjusting structure 43, so that the lower half-ring base piece 212 is coaxial with the azimuth gamma emission short section 11, and the probe marking structure 13 of the azimuth gamma emission short section 11 coincides with the midpoint of the lower half-ring base piece 212. Then install the upper half-ring base piece 211 of the corresponding gamma source base core 21 and the upper half-ring adjusting piece 221 of the gamma source centering 22, so as to assemble the gamma source core 2 with the required radial width. Finally, connect the core cover 412 to the core plate 411 through the connecting member 413 and press and fix the gamma source core 2.

[0087] The above are only several embodiments of the present invention. Those skilled in the art can make various changes or modifications to the embodiments of the present invention without departing from the spirit and scope of the present invention based on the content disclosed in the application documents.

Claims

1. A method for measuring the radial detection depth of a near-bit azimuth gamma logging-while-drilling tool, characterized in that, the measurement method includes: placing the azimuth gamma receiving sub of the near-bit azimuth gamma logging-while-drilling tool around its azimuth gamma transmitting sub; selecting a gamma source core with a matched inner diameter and a certain radiation intensity according to the outer diameter of the azimuth gamma transmitting sub; sheathing the gamma source core outside the azimuth gamma transmitting sub; testing the gamma count rate of the near-bit azimuth gamma logging-while-drilling tool; increasing the outer diameter of the gamma source core to increase its radial width, and testing the gamma count rate of the near-bit azimuth gamma logging-while-drilling tool in the same way as above; until the gamma count rate cannot increase when the gamma source core increases from a target radial width, the target radial width is the radial detection depth of the near-bit azimuth gamma logging-while-drilling tool under a certain radiation intensity; replacing the gamma source core with a different radiation intensity but a matched inner diameter, and measuring the radial detection depths of the near-bit azimuth gamma logging-while-drilling tool under different radiation intensities in the same way as above.

2. The measurement method according to claim 1, characterized in that, the step of placing the azimuth gamma receiving sub around the azimuth gamma transmitting sub includes: placing the azimuth gamma transmitting sub horizontally, and placing the azimuth gamma receiving sub horizontally on the side of the azimuth gamma transmitting sub; wherein, the distance between the azimuth gamma receiving sub and the azimuth gamma transmitting sub is 2 m to 15 m.

3. The measurement method according to claim 1, characterized in that, the gamma source core includes a gamma source base core and a plurality of gamma source centering cores, the step of sheathing the gamma source core outside the azimuth gamma transmitting sub includes the following steps: sheathing the gamma source base core outside the azimuth gamma transmitting sub; or sheathing the gamma source base core outside the azimuth gamma transmitting sub, and then successively sheathing at least one of the gamma source centering cores outside the gamma source base core from the inside to the outside; the step of increasing the outer diameter of the gamma source core to increase its radial width includes: successively sheathing at least another gamma source centering core outside the gamma source base core or the outermost gamma source centering core from the inside to the outside to gradually increase the outer diameter of the gamma source core.

4. The measurement method according to claim 1, characterized in that, the step of sheathing the gamma source core outside the azimuth gamma transmitting sub further includes: adjusting the gamma source core to be coaxial with the azimuth gamma transmitting sub, and the center of the gamma source core is located at the position of the gamma probe of the azimuth gamma transmitting sub.

5. The measurement method according to claim 1, characterized in that, the step of testing the gamma count rate of the near-bit azimuth gamma logging-while-drilling tool includes the following steps: the azimuth gamma transmitting sub remains stationary inside the gamma source core, and testing the gamma count rate of the near-bit azimuth gamma logging-while-drilling tool in the stationary state; The azimuth gamma emission sub-section rotates within the gamma source core to test the gamma count rate of the near-bit azimuth gamma logging-while-drilling tool in a rotating state.

6. According to the measurement method described in claim 5, characterized in that the gamma count rate is the average value of the gamma count rates tested by the near-bit azimuth gamma logging-while-drilling tool within a single test time, where the single test time is greater than or equal to 15 minutes.

7. A measuring device for the radial detection depth of a near-bit azimuth gamma logging-while-drilling tool, characterized in that adopting the measurement method described in any one of claims 1-6, the measuring device includes: a rotating mechanism for installing the azimuth gamma emission sub-section of the near-bit azimuth gamma logging-while-drilling tool and capable of driving the azimuth gamma emission sub-section to rotate; a gamma source core structure including a plurality of gamma source core components with different radiation intensities, and each gamma source core component includes a plurality of gamma source cores with the same inner diameter and different outer diameters, and the inner diameter of the gamma source core matches the outer diameter of the azimuth gamma emission sub-section and can be sleeved outside the azimuth gamma emission sub-section; a gamma source core installation mechanism for installing one of the gamma source cores.

8. According to the measuring device described in claim 7, characterized in that each gamma source core includes a gamma source base core with the same radiation intensity and a plurality of gamma source concentrators. The inner diameter of the gamma source base core of each gamma source core matches the outer diameter of the azimuth gamma emission sub-section and can be sleeved outside the azimuth gamma emission sub-section. The plurality of gamma source concentrators of each gamma source core can be sequentially sleeved outside the corresponding gamma source base core from the inside out to increase the outer diameter of the gamma source core.

9. According to the measuring device described in claim 7, characterized in that the gamma source core structure includes a plurality of gamma source concentrator components and a plurality of gamma source base core components, the radiation intensities of the plurality of gamma source concentrator components are different, and each gamma source concentrator component includes a plurality of gamma source concentrators with inner diameters increasing from small to large and capable of being sequentially sleeved from the inside out; each gamma source base core component includes a plurality of gamma source base cores with the same inner diameter and different radiation intensities. The inner diameters of the gamma source base cores of the plurality of gamma source base core components are different, and the outer diameter of the gamma source base core of each gamma source base core component can match the inner diameter of one of the gamma source concentrators of the gamma source concentrator component with the same radiation intensity, so that each gamma source base core component can be assembled with at least one of the gamma source concentrators of the plurality of gamma source concentrator components into a plurality of gamma source core components.

10. According to the measuring device described in claim 8 or 9, characterized in that the gamma source base core and the gamma source concentrator are both annular. The gamma source base core includes an upper half-ring substrate and a lower half-ring substrate, and the upper half-ring substrate and the lower half-ring substrate are butted to form the gamma source base core. The gamma source concentrator includes an upper half-ring adjusting piece and a lower half-ring adjusting piece, and the upper half-ring adjusting piece and the lower half-ring adjusting piece are butted to form the gamma source concentrator.

11. According to the measuring device described in claim 7, characterized in that The measuring device also includes a test bench, the rotating mechanism is mounted on the test bench, the azimuth gamma emission short section is installed on the rotating mechanism along a horizontal direction, the gamma source core installation mechanism includes a horizontal adjustment mechanism, a lifting adjustment structure and a core clamping structure, the horizontal adjustment structure can be movably arranged on the test bench along the horizontal direction, the lifting adjustment structure can be movably arranged on the horizontal adjustment structure along the vertical direction, and the core clamping structure is installed on the lifting adjustment structure.

12. The measuring device according to claim 11, It is characterized in that The core clamping structure includes a core disk, a core cover and a plurality of connecting pieces. The core disk is installed on the lifting and adjusting structure. The core cover is connected to the core disk through the plurality of connecting pieces. A clamping space for clamping and fixing the gamma source core is formed between the core cover and the core disk.

13. The measuring device according to claim 11, It is characterized in that The horizontal adjustment structure includes a lead screw, a lead screw seat, a sliding base and a sliding matching structure. The sliding base is slidingly matched along the horizontal direction on the test bench through the sliding matching structure. The lead screw seat is fixed on the test bench. One end of the lead screw passes through the lead screw seat and is rotatably connected to the sliding seat, and the lead screw is threadedly connected to the lead screw seat.

14. The measuring device according to claim 11, It is characterized in that The rotating mechanism includes a motor, a transmission structure, a first core shaft, a second core shaft, a first adapter structure and a second adapter structure. The two ends of the azimuth gamma emission short section are connected to the first core shaft and the second core shaft. The first core shaft is rotatably installed on the test bench through the first adapter structure. The second core shaft is rotatably installed on the test bench through the second adapter structure. The rotating shaft of the motor is connected to the first core shaft through the transmission structure and can drive the first core shaft to rotate through the transmission structure.

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