Logging-while-drilling remote gamma measurement device

Abstract

This utility model discloses a remote gamma measurement device for logging while drilling. The remote gamma measurement device includes: a pressure-resistant cylinder, a mounting frame, a main control and power board, a gamma sensor, a metal shielding sleeve, a shielding layer, a first connector assembly, and a second connector assembly. The mounting frame is located inside the pressure-resistant cylinder; the main control and power board is located on the mounting frame; the gamma sensor is located on the mounting frame and electrically connected to the main control and power board, and the gamma sensor includes a photomultiplier tube and a NaI crystal; the metal shielding sleeve is fitted over the photomultiplier tube; the shielding layer is located inside the pressure-resistant cylinder and is used to shield the peripheral area of ​​the gamma sensor; the first connector assembly is located on the pressure-resistant cylinder and electrically connected to the main control and power board; the second connector assembly is located on the pressure-resistant cylinder and electrically connected to the gamma sensor. This utility model's remote gamma measurement device for logging while drilling can reduce the influence of external signals on the photomultiplier tube and improve the reliability of the remote gamma measurement device for logging while drilling.

Description

Technical Field

[0001] This utility model relates to the field of downhole exploration technology, and in particular to a remote gamma measurement device for logging while drilling. Background Technology

[0002] Electronic modules such as the preamplifier and signal processing circuit of the remote gamma measurement device for logging while drilling are susceptible to electromagnetic interference (EMI), especially high-frequency electromagnetic waves, which may couple into the circuit, introducing noise or baseline drift and affecting energy resolution and counting accuracy.

[0003] Furthermore, there are numerous measurement-while-drilling (MWD) instruments, sequentially positioned at various locations on the drill collar. If each instrument were to establish a communication connection with the ground system via its own antenna, severe interference between the wireless signals would result, leading to poor communication quality and high energy consumption. Therefore, signals from multiple instruments located close to each other are typically combined and communicate with the ground system using a single communication module. The instruments sharing this module communicate with each other via a bus. When the bus passes through the remote gamma measurement unit (RTU) during MWD, it can interfere with the RTU, affecting its operational reliability. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. Therefore, one objective of this invention is to provide a remote gamma measurement device for logging while drilling, which can reduce the influence of external signals on the photomultiplier tube and improve the reliability of the remote gamma measurement device.

[0005] A remote gamma measurement device for logging while drilling according to an embodiment of this utility model includes: a pressure-resistant cylinder, a mounting frame, a main control and power board, a gamma sensor, a metal shielding sleeve, a shielding layer, a first connector assembly, and a second connector assembly. The mounting frame is disposed inside the pressure-resistant cylinder; the main control and power board is disposed on the mounting frame; the gamma sensor is disposed on the mounting frame and electrically connected to the main control and power board, the gamma sensor including a photomultiplier tube and a NaI crystal, the photomultiplier tube being disposed on the side of the NaI crystal closer to the main control and power board; the metal shielding sleeve is fitted over the photomultiplier tube; the shielding layer is disposed inside the pressure-resistant cylinder to shield a portion of the peripheral area of ​​the gamma sensor; the first connector assembly is disposed on the pressure-resistant cylinder and electrically connected to the main control and power board; the second connector assembly is disposed on the pressure-resistant cylinder and electrically connected to the gamma sensor.

[0006] According to the embodiment of the present invention, the remote gamma measurement device for logging while drilling has a metal shielding sleeve over a photomultiplier tube, which can be used to shield external signals, reduce the influence of external signals on the photomultiplier tube, and thus reduce the influence of external signals on the measurement results of the remote gamma measurement device for logging while drilling, thereby helping to improve the reliability of the remote gamma measurement device for logging while drilling.

[0007] In some embodiments of this utility model, a first step is provided on the outer side of the metal shielding sleeve, and the remote gamma measurement device for logging while drilling includes a temperature detection element, which is located on the outer side of the metal shielding sleeve and abuts against the first step.

[0008] In some embodiments of this utility model, the metal shielding sleeve includes a first part, a second part, and a transition part. The first part and the second part are connected through the transition part. The first part is further away from the NaI crystal than the second part. The inner diameter of the first part is smaller than the inner diameter of the second part. A first step is formed between the transition part and the first part.

[0009] In some embodiments of this utility model, the thickness of the transition portion is greater than the wall thickness of the first portion and greater than the wall thickness of the second portion.

[0010] In some embodiments of this utility model, in the axial direction of the pressure-resistant cylinder, the length of the first part is greater than the length of the second part, and the length of the second part is greater than the length of the transition part.

[0011] In some embodiments of this utility model, the transition portion has an inner surface, which includes a straight section and an inclined section connected together. The straight section connects to the first portion and is coplanar with the inner wall surface of the first portion, and the inclined section connects to the second portion.

[0012] In some embodiments of this utility model, the remote gamma measurement device for logging while drilling includes a heat-conducting sleeve, which is fitted over the metal shielding sleeve and the NaI crystal, and can conduct the heat of the NaI crystal to the mounting frame.

[0013] In some embodiments of this utility model, the inner side of the heat-conducting sleeve is provided with a second step, and the end of the temperature detection element away from the first step abuts against the second step.

[0014] In some embodiments of this utility model, the heat-conducting sleeve includes a first cylindrical portion and a second cylindrical portion, the first cylindrical portion is sleeved on the metal shielding sleeve, the second cylindrical portion is sleeved on the metal shielding sleeve and the NaI crystal, and the first cylindrical portion is provided with a second step.

[0015] In some embodiments of this utility model, the metal shielding sleeve is at least closed at one end near the NaI crystal.

[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0018] Figure 1 A three-dimensional structural schematic diagram of the remote gamma measurement device for logging while drilling provided in some embodiments of this utility model;

[0019] Figure 2 A front view of a portion of the structure of a remote gamma measurement device for logging while drilling provided in some embodiments of this utility model;

[0020] Figure 3 Exploded structural diagrams of a portion of the remote gamma measurement device for logging while drilling provided in some embodiments of this utility model;

[0021] Figure 4 A top view of a portion of the structure of a remote gamma measurement device for logging while drilling provided in some embodiments of this utility model;

[0022] Figure 5 A cross-sectional view of a portion of the structure of a remote gamma measurement device for logging while drilling provided in some embodiments of this utility model;

[0023] Figure 6 for Figure 5 Enlarged view of section II;

[0024] Figure 7 for Figure 5 A magnified view of section I.

[0025] Figure label:

[0026] 100. Remote gamma measurement device for logging while drilling;

[0027] 10. Compression cylinder;

[0028] 20. Install the frame; 20a. Install the slot;

[0029] 30. Main control and power supply board;

[0030] 40. Gamma sensor; 41. Photomultiplier tube; 42. NaI crystal;

[0031] 50. Shielding layer;

[0032] 60. Metal shielding sleeve; 60a. Second through hole; 61. First part; 62. Second part; 63. Transition part; 63a. Inner surface; 63b. Straight section; 63c. Sloping section; 64. First step;

[0033] 70. Heat-conducting sleeve; 71. First cylindrical section; 71a. First through hole; 72. Second cylindrical section; 73. Butt joint position; 74. Second step;

[0034] 80. First connector assembly;

[0035] 90. Second connector assembly;

[0036] 110. Temperature detection components. Detailed Implementation

[0037] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0038] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0039] Furthermore, features specified as "first" or "second" may explicitly or implicitly include one or more of the same feature, used to distinguish and describe features, without any order or distinction of importance.

[0040] In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0041] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0042] The following is for reference. Figures 1-5 This describes the remote gamma measurement device 100 for logging while drilling, according to an embodiment of the present invention.

[0043] like Figures 1 to 4 As shown, the remote gamma measurement device 100 for logging while drilling according to this utility model includes: a pressure-resistant cylinder 10, a mounting frame 20, a main control and power board 30, a gamma sensor 40, a metal shielding sleeve 60, a shielding layer 50, a first connector assembly 80, and a second connector assembly 90.

[0044] The mounting frame 20 is located inside the pressure-resistant cylinder 10; the main control and power board 30 is located on the mounting frame 20; the gamma sensor 40 is located on the mounting frame 20 and is electrically connected to the main control and power board 30. The gamma sensor includes a photomultiplier tube 41 and a NaI crystal 42. The photomultiplier tube 41 is located on the side of the NaI crystal 42 closer to the main control and power board 30; a metal shielding sleeve 60 is fitted over the photomultiplier tube 41; a shielding layer 50 is located inside the pressure-resistant cylinder 10 and is used to shield the peripheral area of ​​the gamma sensor 40; a first connector assembly 80 is located on the pressure-resistant cylinder 10 and is electrically connected to the main control and power board 30; a second connector assembly 90 is located on the pressure-resistant cylinder 10 and is electrically connected to the gamma sensor 40.

[0045] The pressure-resistant cylinder 10 can refer to a component that is installed around the mounting frame 20. It can be used to isolate external mud and prevent external mud from entering the remote gamma measurement device 100 during drilling.

[0046] The main control and power board 30 can refer to the control circuit and the component that processes and amplifies the signal from the gamma sensor 40. The connection method with the mounting frame 20 can be, but is not limited to, adhesive bonding, bolt connection, riveting, etc.

[0047] The gamma sensor 40 refers to a component that receives the intensity of gamma rays, and is mounted on the mounting frame 20 and electrically connected to the main control and power board 30. In the above technical solution, the gamma sensor 40 may include a photomultiplier tube 41 and a NaI crystal 42, with the photomultiplier tube 41 located on the side of the NaI crystal 42 closer to the main control and power board 30. The NaI crystal 42 can be used to convert gamma rays into fluorescent photons with a wavelength of 415 nm through interactions such as the photoelectric effect. The photomultiplier tube 41 can be used to convert the weak scintillation light emitted by the NaI crystal 42 into an electrical signal, and amplify it through multiple stages of dynamometers to output a measurable current pulse.

[0048] The metal shielding sleeve 60 can refer to a component that shields external signals, and can be, but is not limited to, high-density tungsten alloy, lead or lead-antimony alloy, stainless steel, Hastelloy, and titanium alloy, etc. For example, the material of the metal shielding sleeve 60 can be stainless steel, which can shield external signals, is corrosion-resistant and has high strength, is suitable for harsh environments, and has a low cost.

[0049] The shielding layer 50 can refer to a component used to shield gamma ray signals, and the material can be composed of a high-density tungsten-nickel-iron alloy. The shielding layer 50 is located inside the pressure-resistant cylinder 10. This can be understood as the shielding layer 50 being located on the gamma sensor 40, on the mounting frame 20, or on the inner wall of the pressure-resistant cylinder 10. For example, see reference... Figure 2 The shielding layer 50 can be installed on the frame 20.

[0050] The first connector assembly 80 can refer to the component that electrically connects the main control unit and the power supply board 30. Additionally, because downhole oil drilling instruments require many functions, and the logging-while-drilling remote gamma measurement device 100 can only measure downhole gamma values, the first connector assembly 80 can also be connected to an external PCD probe. The PCD probe is an additional functional instrument primarily used to measure the wellbore inclination and azimuth of the instrument string.

[0051] The second connector assembly 90 can refer to the component that electrically connects to the gamma sensor 40, or it can be rigidly connected to an external connection. The rigid connection allows for adjustment of the instrument string length, facilitating the operation of the remote gamma measurement device 100 during drilling.

[0052] Understandably, when the external bus passes through the gamma detector 40, it will interfere with the gamma detector 40. The metal shielding sleeve 60 can shield the signal, reducing the impact of external signals on the photomultiplier tube 41. Secondly, the bus of the remote gamma measurement device 100 for logging while drilling can adopt a twisted-pair structure. When the two wires of the twisted-pair bus are twisted together, the external interference magnetic field will generate induced currents in opposite directions in adjacent loops, canceling each other out and reducing interference with the gamma detector signal. Therefore, the bus uses a twisted-pair structure to transmit differential signals, which works in conjunction with the metal shielding sleeve 60 to reduce the impact of external signals on the photomultiplier tube 41.

[0053] According to the embodiment of the present utility model, the remote gamma measurement device 100 for logging while drilling has a metal shielding sleeve 60 that is fitted over the photomultiplier tube 41. This can be used to shield external signals, reduce the influence of external signals on the photomultiplier tube 41, and thus reduce the influence of external signals on the measurement results of the remote gamma measurement device 100 for logging while drilling. This helps to improve the reliability of the remote gamma measurement device 100 for logging while drilling.

[0054] In some embodiments of this utility model, reference is made to Figure 4 and Figure 5 The outer side of the metal shielding sleeve 60 is provided with a first step 64. The remote gamma measurement device 100 for logging while drilling includes a temperature detection element 110, which is located on the outer side of the metal shielding sleeve 60 and abuts against the first step 64.

[0055] In the above technical solution, the first step 64 can be used to position and install the temperature detection element 110, and can also improve the space utilization of the gamma sensor 40. The temperature detection element 110 can indirectly monitor the temperature of the NaI crystal 42 in real time, thereby compensating for the deviation of the detection results caused by temperature changes and improving the reliability of the detection results of the remote gamma measurement device 100 for logging while drilling.

[0056] In some embodiments of this utility model, reference is made to Figure 5 and Figure 6 The metal shielding sleeve 60 includes a first part 61, a second part 62 and a transition part 63. The first part 61 and the second part 62 are connected by the transition part 63. The first part 61 is further away from the NaI crystal 42 than the second part 62. The inner diameter of the first part 61 is smaller than the inner diameter of the second part 62. A first step 64 is formed between the transition part 63 and the first part 61.

[0057] In the above technical solution, the first part 61 and the second part 62 are connected by a transition part 63, which can disperse stress, improve the structural strength of the metal shielding sleeve 60, and thus improve the reliability of the metal shielding sleeve 60. The inner diameter of the first part 61 is smaller than the inner diameter of the second part 62, which can save materials and reduce costs. A first step 64 is formed between the transition part 63 and the first part 61, which can be used for positioning and installing the temperature detection element 110, and can also improve the space utilization of the gamma sensor 40.

[0058] In some embodiments of this utility model, reference is made to Figure 5 and Figure 6 The thickness of the transition portion 63 is greater than the wall thickness of the first portion 61 and greater than the wall thickness of the second portion 62.

[0059] In the above technical solution, the thickness of the transition portion 63 is greater than the wall thickness of the first portion 61, which can improve the structural rigidity of the transition portion 63, avoid cracks or fractures caused by fatigue stress, and improve the reliability of the metal shielding sleeve 60. At the same time, the thickened transition portion 63 can also compensate for electromagnetic leakage (such as gap effect) that may occur due to changes in inner diameter, ensure a smooth transition of shielding performance from the first portion 61 to the second portion 62, avoid the penetration of high-frequency interference signals, and further improve the reliability of the metal shielding sleeve 60.

[0060] In some embodiments of this utility model, reference is made to Figure 5 In the axial direction of the pressure-resistant cylinder 10, the length of the first part 61 is greater than the length of the second part 62, and the length of the second part 62 is greater than the length of the transition part 63.

[0061] In the above technical solution, the first part 61 is longer, providing a longer continuous shielding area that completely covers the sensitive operating section of the photomultiplier tube 41, effectively isolating electromagnetic interference generated by external structures such as the bus, and ensuring the reliability of the photomultiplier tube 41. The second part 62 is shorter, retaining basic shielding functions and further ensuring the reliability of the photomultiplier tube 41.

[0062] In some embodiments of this utility model, reference is made to Figure 5 and Figure 6 The transition portion 63 has an inner surface 63a, which includes a straight section 63b and a sloped section 63c connected together. The straight section 63b connects to the first portion 61 and is coplanar with the inner wall surface of the first portion 61. The sloped section 63c connects to the second portion 62.

[0063] In the above technical solution, the design of the straight section 63b and the inclined section 63c can achieve uniform stress distribution, improve the structural strength of the transition part 63, and further improve the structural strength of the metal shielding sleeve 60.

[0064] In some embodiments of this utility model, reference is made to Figure 5 The logging-while-drilling remote gamma measurement device 100 includes a heat-conducting sleeve 70, which is fitted over a metal shielding sleeve 60 and a NaI crystal 42, and can conduct the heat of the NaI crystal 42 to the mounting frame 20.

[0065] In the above technical solution, the heat-conducting sleeve 70 is wrapped around the metal shielding sleeve 60 and the NaI crystal 42, which can transfer the heat of the NaI crystal 42 to the mounting frame 20, thereby reducing the temperature of the NaI crystal 42 and reducing the risk that the measurement results of the remote gamma measurement device 100 for logging while drilling will be affected due to the excessive temperature of the NaI crystal 42. This is beneficial to improving the reliability of the remote gamma measurement device 100 for logging while drilling.

[0066] In some embodiments of this utility model, reference is made to Figure 5 and Figure 7 The inner side of the heat-conducting sleeve 70 is provided with a second step 74, and the end of the temperature detection element 110 away from the first step 64 abuts against the second step 74.

[0067] In the above technical solution, the end of the temperature sensing element 110 away from the first step 64 abuts against the second step 74, which facilitates the installation and positioning of the temperature sensing element 110, and can also limit the temperature sensing element 110, thereby improving the reliability of the temperature sensing element 110.

[0068] In some embodiments of this utility model, reference is made to Figure 5 and Figure 6 The heat-conducting sleeve 70 includes a first cylindrical portion 71 and a second cylindrical portion 72. The first cylindrical portion 71 is fitted over a metal shielding sleeve 60, and the second cylindrical portion 72 is fitted over a metal shielding sleeve 60 and a NaI crystal 42. The first cylindrical portion 71 is provided with a second step 74.

[0069] The connection method between the first cylindrical part 71 and the second cylindrical part 72 can be, but is not limited to, welding, riveting, bolting, snap-fitting, flange connection, adhesive bonding, threaded connection, etc.

[0070] It is understandable that the closed end of the first cylindrical part 71 is provided with a first through hole 71a, and the metal shielding sleeve 60 is provided with a second through hole 60a. The second through hole 60a is connected to the first through hole 71a and can be used for the gamma sensor 40 to electrically connect to the main control and power board 30.

[0071] In the above technical solution, the design of the first cylindrical section 71 and the second cylindrical section 72 reduces the installation difficulty of the temperature detection element 110 and improves the assembly efficiency of the remote gamma measurement device 100 for logging while drilling. The first cylindrical section 71 is provided with a second step 74, which can abut against the temperature detection element 110, facilitating its installation and positioning, and also limiting its movement, thereby improving the reliability of the temperature detection element 110.

[0072] In some embodiments of this utility model, reference is made to Figure 5 The heat-conducting sleeve 70 is cylindrical, and the gamma sensor 40 is sleeved inside the heat-conducting sleeve 70.

[0073] In the above technical solution, the heat-conducting sleeve 70 is cylindrical, which can increase the contact surface with the gamma sensor 40, form a uniform heat conduction interface, avoid local overheating, improve the heat conduction efficiency of the heat-conducting sleeve 70, and further improve the reliability of the remote gamma measurement device 100 for logging while drilling.

[0074] In some embodiments of this utility model, reference is made to Figure 5 The gamma sensor 40 includes a photomultiplier tube 41 and a NaI crystal 42. The photomultiplier tube 41 is located on the side of the NaI crystal 42 close to the main control and power board 30. The heat-conducting sleeve 70 covers at least the side and end face of the NaI crystal 42.

[0075] NaI crystal 42 can be used to convert gamma rays into fluorescent photons with a wavelength of 415 nm through interactions such as the photoelectric effect.

[0076] The photomultiplier tube 41 can be used to convert the weak scintillation light emitted by the NaI crystal 42 into an electrical signal, and amplify it through a multi-stage multiplier to output a measurable current pulse.

[0077] In the above technical solution, optionally, the heat-conducting sleeve 70 can only wrap the sides and end faces of the NaI crystal 42. Since the heat generated by the gamma sensor 40 mainly comes from the NaI crystal 42, by wrapping only the sides and end faces of the NaI crystal 42 with the heat-conducting sleeve 70, the heat-conducting sleeve 70 can provide good heat conduction for the gamma sensor 40 while reducing the amount of material used and lowering costs. Optionally, the heat-conducting sleeve 70 can also wrap the sides and end faces of the NaI crystal 42 and the photomultiplier tube 41, which can further increase the heat conduction area and enhance the heat conduction effect on the gamma sensor 40.

[0078] Understandably, the heat-conducting sleeve 70 at least covers the sides and ends of the NaI crystal 42, which can form an efficient heat conduction path, quickly dissipate the heat generated by the absorption of gamma rays by the NaI crystal 42, avoid damage to the NaI crystal 42 at high temperatures, and improve the reliability of the remote gamma measurement device 100 for logging while drilling.

[0079] In some embodiments of this utility model, reference is made to Figure 3 and Figure 5 The mounting frame 20 is provided with a mounting groove 20a, and the heat-conducting sleeve 70 and the gamma sensor 40 are disposed in the mounting groove 20a. The peripheral side of the heat-conducting sleeve 70 contacts the mounting groove 20a, and at least one end of the heat-conducting sleeve 70 in the axial direction contacts the mounting groove 20a.

[0080] The axial direction of the heat-conducting sleeve 70 can be referenced. Figure 3 The left and right directions.

[0081] It is understood that the heat-conducting sleeve 70 can contact the mounting groove 20a at one end in the axial direction, or at both ends in the axial direction. The shape of the mounting groove 20a can match the shape of the gamma sensor 40, which can be, but is not limited to, cylindrical, rectangular, etc. For example, the gamma sensor 40 can be cylindrical, and the mounting groove 20a can be a semi-circular groove.

[0082] In the above technical solution, the peripheral side of the heat-conducting sleeve 70 contacts the mounting groove 20a, and at least one end of the heat-conducting sleeve 70 in the axial direction contacts the mounting groove 20a. This can increase the contact area between the heat-conducting sleeve 70 and the mounting groove 20a, improve the heat conduction efficiency of the heat-conducting sleeve 70, and reduce the risk of high-temperature damage to the NaI crystal 42.

[0083] In some embodiments of this utility model, reference is made to Figure 4 and Figure 5 The heat-conducting sleeve 70 includes a first cylindrical part 71 and a second cylindrical part 72. The first cylindrical part 71 and the second cylindrical part 72 are arranged and connected along the axial direction of the pressure-resistant sleeve 10. The ends of the first cylindrical part 71 and the second cylindrical part 72 that are away from each other are closed ends. The first cylindrical part 71 is closer to the main control and power board 30 than the second cylindrical part.

[0084] The connection method between the first cylindrical part 71 and the second cylindrical part 72 can be, but is not limited to, welding, riveting, bolting, snap-fitting, flange connection, adhesive bonding, threaded connection, etc.

[0085] Understandably, the closed end of the first cylindrical section 71 is provided with a through hole, which can be used for the gamma sensor 40 to electrically connect to the main control and power board 30.

[0086] In the above technical solution, the first cylinder 71 and the second cylinder 72 are arranged and connected along the axial direction of the pressure-resistant cylinder 10. This allows the first cylinder 71 and the second cylinder 72 to be installed at both ends of the gamma sensor 40, respectively. Compared with the integrated heat-conducting component 70, the first cylinder 71 and the second cylinder 72 are smaller in size, which facilitates assembly, reduces the installation difficulty of the heat-conducting sleeve 70, and improves the assembly efficiency of the remote gamma measurement device 100 for logging while drilling.

[0087] In some embodiments of this utility model, reference is made to Figure 5 The gamma sensor 40 includes a photomultiplier tube 41 and a NaI crystal 42. The photomultiplier tube 41 is located on the side of the NaI crystal 42 close to the main control and power board 30. A docking position 73 is provided between the first cylindrical part 71 and the second cylindrical part 72. The docking position 73 is located between the two end faces of the photomultiplier tube 41 in the axial direction of the pressure-resistant cylinder 10.

[0088] In the above technical solution, the docking position 73 is located between the two end faces of the photomultiplier tube 41 in the axial direction of the pressure-resistant cylinder 10. This can reduce the risk that the fastening method of the docking position 73 may transmit mechanical stress to the NaI crystal 42, thereby reducing the probability of damage to the NaI crystal 42 and improving the reliability of the gamma sensor 40.

[0089] In some embodiments of this utility model, reference is made to Figure 5 The logging-while-drilling remote gamma measurement device 100 includes a temperature detection element 110, which is located inside the heat-conducting sleeve 70. A docking position 73 is provided between the first cylinder 71 and the second cylinder 72. The docking position 73 is located between the two end faces of the temperature detection element 110 in the axial direction of the pressure-resistant cylinder 10.

[0090] In the above technical solution, the docking position 73 is located between the two end faces of the temperature sensing element 110 in the axial direction of the pressure-resistant cylinder 10. This facilitates the installation of the temperature sensing element 110 and allows for real-time indirect monitoring of the temperature of the NaI crystal 42, thereby compensating for deviations in the detection results caused by temperature changes and further improving the reliability of the detection results from the remote gamma measurement device 100 during drilling. Since the first cylinder 71 and the second cylinder 72 are docked at the docking position 73, and the docking position 73 is located between the two end faces of the temperature sensing element 110 in the axial direction of the pressure-resistant cylinder 10, the temperature sensing element 110 is close to the splicing position of the first cylinder 71 and the second cylinder 72, making it convenient to assemble the temperature sensing element 110 inside the heat-conducting sleeve 70.

[0091] In some embodiments of this utility model, reference is made to Figure 5 The metal shielding sleeve 60 is closed at least at one end near the NaI crystal 42. Optionally, both ends of the metal shielding sleeve 60 may be closed. Alternatively, the end of the metal shielding sleeve 60 near the NaI crystal 42 may also be closed.

[0092] In the above technical solution, the metal shielding sleeve 60 is closed at least at one end close to the NaI crystal 42, which can improve the signal shielding capability of the metal shielding sleeve 60, further avoid the influence of external signals on the photomultiplier tube 41, and improve the reliability of the metal shielding sleeve 60.

[0093] The following is combined with Figures 1 to 5 This describes a specific embodiment of the remote gamma measurement device 100 for logging while drilling according to this utility model.

[0094] The remote gamma measurement device 100 for logging while drilling includes: a pressure-resistant cylinder 10, a mounting frame 20, a main control and power board 30, a gamma sensor 40, a shielding layer 50, a metal shielding sleeve 60, a heat-conducting sleeve 70, a first connector assembly 80, a second connector assembly 90, and a temperature detection element 110.

[0095] The mounting frame 20 is installed inside the pressure-resistant cylinder 10.

[0096] The main control and power board 30 are mounted on the mounting frame 20.

[0097] The gamma sensor 40 is mounted on the mounting frame 20 and electrically connected to the main control and power board 30. The gamma sensor includes a photomultiplier tube 41 and a NaI crystal 42. The photomultiplier tube 41 is located on the side of the NaI crystal 42 closer to the main control and power board 30.

[0098] The shielding layer 50 is located inside the pressure-resistant cylinder 10 and is used to shield the peripheral area of ​​the gamma sensor 40.

[0099] A metal shielding sleeve 60 is fitted over a photomultiplier tube 41 and includes a first part 61, a second part 62, and a transition part 63. The first part 61 and the second part 62 are connected by the transition part 63. The first part 61 is further away from the NaI crystal 42 than the second part 62. The inner diameter of the first part 61 is smaller than the inner diameter of the second part 62. A first step 64 is formed between the transition part 63 and the first part 61. The thickness of the transition part 63 is greater than the wall thickness of the first part 61 and greater than the wall thickness of the second part 62. In the axial direction of the pressure-resistant cylinder 10, the length of the first part 61 is greater than the length of the second part 62, and the length of the second part 62 is greater than the length of the transition part 63. The transition part 63 has an inner surface 63a, which includes a connected straight section 63b and a sloped section 63c. The straight section 63b connects to the first part 61 and is coplanar with the inner wall surface of the first part 61. The sloped section 63c connects to the second part 62. The two ends of the metal shielding sleeve 60 are closed.

[0100] The heat-conducting sleeve 70 is fitted over the metal shielding sleeve 60 and the NaI crystal 42, and can conduct heat from the NaI crystal 42 to the mounting frame 20. The heat-conducting sleeve 70 includes a first cylindrical portion 71 and a second cylindrical portion 72. The first cylindrical portion 71 is fitted over the metal shielding sleeve 60, and the second cylindrical portion 72 is fitted over the metal shielding sleeve 60 and the NaI crystal 42. The first cylindrical portion 71 is provided with a second step 74.

[0101] The first connector assembly 80 is located on the pressure-resistant cylinder 10 and is electrically connected to the main control and power supply board 30.

[0102] The second connector assembly 90 is located on the pressure-resistant cylinder 10 and is electrically connected to the gamma sensor 40.

[0103] The temperature detection element 110 is a temperature sensor, located on the outside of the metal shielding sleeve 60, and abuts against the first step 64.

[0104] In the description of this specification, references to terms such as "some embodiments," "optionally," "furthermore," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0105] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A remote gamma measurement device for logging while drilling, characterized in that, include: Pressure-resistant cylinder; The mounting frame is disposed inside the pressure-resistant cylinder; The main control and power supply board are mounted on the mounting frame. A gamma sensor is mounted on the mounting frame and electrically connected to the main control and power board. The gamma sensor includes a photomultiplier tube and a NaI crystal. The photomultiplier tube is located on the side of the NaI crystal closer to the main control and power board. A metal shielding sleeve is fitted over the photomultiplier tube. A shielding layer is disposed inside the pressure-resistant cylinder to shield the peripheral area of ​​the gamma sensor. The first connector assembly is disposed on the pressure-resistant cylinder and electrically connected to the main control and power supply board; The second connector assembly is disposed on the pressure-resistant cylinder and electrically connected to the gamma sensor.

2. The remote gamma measurement device for logging while drilling according to claim 1, characterized in that, The outer side of the metal shielding sleeve is provided with a first step, and the remote gamma measurement device for logging while drilling includes a temperature detection element, which is located on the outer side of the metal shielding sleeve and abuts against the first step.

3. The remote gamma measurement device for logging while drilling according to claim 2, characterized in that, The metal shielding sleeve includes a first part, a second part, and a transition part. The first part and the second part are connected through the transition part. The first part is further away from the NaI crystal than the second part. The inner diameter of the first part is smaller than the inner diameter of the second part. A first step is formed between the transition part and the first part.

4. The remote gamma measurement device for logging while drilling according to claim 3, characterized in that, The thickness of the transition portion is greater than the wall thickness of the first portion and greater than the wall thickness of the second portion.

5. The remote gamma measurement device for logging while drilling according to claim 3 or 4, characterized in that, In the axial direction of the pressure-resistant cylinder, the length of the first part is greater than the length of the second part, and the length of the second part is greater than the length of the transition part.

6. The remote gamma measurement device for logging while drilling according to claim 3 or 4, characterized in that, The transition portion has an inner surface, which includes a straight section and a sloped section connected together. The straight section connects to the first portion and is coplanar with the inner wall surface of the first portion. The sloped section connects to the second portion.

7. The remote gamma measurement device for logging while drilling according to claim 2, characterized in that, The remote gamma measurement device for logging while drilling includes a heat-conducting sleeve, which is fitted over the metal shielding sleeve and the NaI crystal, and can conduct the heat from the NaI crystal to the mounting frame.

8. The remote gamma measurement device for logging while drilling according to claim 7, characterized in that, The inner side of the heat-conducting sleeve is provided with a second step, and the end of the temperature detection element away from the first step abuts against the second step.

9. The remote gamma measurement device for logging while drilling according to claim 8, characterized in that, The heat-conducting sleeve includes a first cylindrical portion and a second cylindrical portion. The first cylindrical portion is fitted over the metal shielding sleeve, and the second cylindrical portion is fitted over the metal shielding sleeve and the NaI crystal. The first cylindrical portion is provided with a second step.

10. The remote gamma measurement device for logging while drilling according to claim 1, characterized in that, The metal shielding sleeve is closed at least at one end near the NaI crystal.

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