A short sub shielding structure for a while-drilling density instrument

Abstract

The application discloses a short joint shielding structure of a while-drilling density instrument, which comprises a drill collar body, a mounting hole arranged on the drill collar body, a density source detachably connected in the mounting hole, a detector assembly arranged on the drill collar body, a shielding assembly arranged on the drill collar body and located between the density source and the detector assembly to shield gamma rays, and a source window arranged on the drill collar body and the shielding assembly and corresponding to the density source. The application can effectively shield gamma rays, thereby improving the measurement accuracy.

Description

Technical Field

[0001] This invention belongs to the field of logging instrument technology, specifically relating to a shielding structure for a short section used in drilling density measurement. Background Technology

[0002] In the exploration and development of energy resources such as oil, natural gas, and coalbed methane, well logging technology is a key means of obtaining underground geological information and evaluating reservoir characteristics. Among them, density logging, as an important core logging method, provides geological engineers with core parameters for lithology identification, porosity calculation, gas saturation assessment, and formation pressure prediction by measuring the volumetric density of the formation.

[0003] Existing density logging instruments typically consist of a short section, a density source, and a detector. The density source emits gamma rays into the formation, which collide with and scatter electrons in the formation before being received by the detector. Since the intensity of the scattered rays is proportional to the electron density of the formation, and thus related to the bulk density of the formation, the density value of the formation can be calculated by measuring the intensity of the scattered rays.

[0004] However, the lack of an effective shielding structure between the density source and the detector in the relevant technology makes it difficult to effectively shield gamma rays, thus affecting the measurement accuracy and requiring improvement. Summary of the Invention

[0005] To address all or some of the aforementioned problems, the present invention aims to provide a short-section shielding structure for drilling density measurement instruments that can effectively shield gamma rays, thereby improving measurement accuracy.

[0006] This invention provides a shielding structure for a short section used in drilling density measurement, comprising: Drill collar body; Mounting holes are provided on the drill collar body; The density source is detachably connected to the mounting hole; A detector assembly is mounted on the drill collar body; A shielding assembly is disposed on the drill collar body and located between the density source and the detector assembly to shield gamma rays; The source window is set on the drill collar body and the shielding assembly, and is set in correspondence with the density source.

[0007] Optionally, the shielding component includes: A side shielding block is disposed on the drill collar body; An upper shielding block is disposed on the drill collar body; A shielding cylinder is coaxially disposed within the drill collar body; The side shielding block is located between the density source and the detector assembly, while the upper shielding block and the shielding cylinder are located on both sides of the density source.

[0008] Optionally, the drill collar body is provided with a first limiting groove, the side shielding block is tightly inserted into the first limiting groove, the drill collar body is detachably connected with a shielding cover plate, the shielding cover plate is provided with a second limiting groove, the upper shielding block is tightly inserted into the second limiting groove, and the shielding cover plate is used to press the side shielding block and the upper shielding block together.

[0009] Optionally, a shock-absorbing pad is provided in the first limiting groove, and the side shielding block is in close contact with the shock-absorbing pad.

[0010] Optionally, the drill collar body is provided with a first source hole, the upper shielding block is provided with a second source hole, and the shielding cover is provided with a third source hole. The first source hole, the second source hole, and the third source hole are aligned with each other and together form the source window. The opening side of the source window is inclined toward the detector assembly, and the inner wall of the source window has an flared structure.

[0011] Optionally, the drill collar body is provided with a release groove, and the first source hole is located between the first limiting groove and the release groove.

[0012] Optionally, the detector assembly includes: A third limiting groove is provided on the drill collar body; The remote detector is tightly fitted into the third limiting groove; The near detector is tightly fitted into the third limiting groove, and the near detector is located between the far detector and the shielding component; The detector cover plate is detachably connected to the drill collar body and is used to press the far detector and the near detector together. A fourth limiting groove is provided on the detector cover plate, and the far detector and the near detector are respectively inserted into the fourth limiting groove.

[0013] Optionally, a buffer pad is provided in the third limiting groove, and the far detector and the near detector are respectively in close contact with the buffer pad.

[0014] Optionally, the drill collar body is provided with a positioning post, the detector cover is provided with a positioning hole, and the positioning post is tightly inserted into the positioning hole.

[0015] Optionally, the far detector and the near detector each include a shielding shell, a detector body, a shielding end cap, and an elastic element. The detector body is tightly inserted into the shielding shell, the shielding end cap is detachably connected to the opening side of the shielding shell, and the elastic element is disposed between the detector body and the shielding end cap.

[0016] As can be seen from the above technical solution, the shielding structure for the drilling density instrument measurement sub provided by the present invention has the following advantages: The short-section shielding structure of the density-while-drilling instrument effectively shields gamma rays by adding a shielding component between the density source and the detector, thereby improving measurement accuracy.

[0017] Other features and advantages of the present invention will be set forth in the following description. Attached Figure Description

[0018] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0019] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a cross-sectional view of an embodiment of the present invention; Figure 3 for Figure 2 Enlarged view of region A in the middle; Figure 4 This is a front view of the drill collar body in an embodiment of the present invention; Figure 5 for Figure 2 A magnified view of region B in the middle.

[0020] Explanation of reference numerals in the attached figures: 1. Drill collar body; 2. Mounting hole; 3. Density source; 4. Detector assembly; 41. Far detector; 42. Near detector; 43. Third limiting groove; 44. Detector cover plate; 45. Fourth limiting groove; 46. Buffer pad; 5. Shielding assembly; 51. Side shielding block; 52. Upper shielding block; 53. Shielding cylinder; 54. First limiting groove; 55. Shielding cover plate; 56. Second limiting groove; 57. Shock-absorbing pad; 6. Source window; 61. First source hole; 62. Second source hole; 63. Third source hole; 7. Release groove; 8. Positioning post; 9. Positioning hole; 10. Shielding shell; 11. Detector body; 12. Shielding end cap; 13. Elastic component. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be arbitrarily combined with each other.

[0022] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 The illustration shows an embodiment of the present invention, which discloses a shielding structure for a drilling density instrument measurement sub. The structure includes a drill collar body 1, with a mounting hole 2 radially disposed on the drill collar body 1, and a density source 3 threadedly connected to the mounting hole 2. A detector assembly 4 and a shielding assembly 5 are disposed on the drill collar body 1, with the shielding assembly 5 located between the density source 3 and the detector assembly 4 to shield gamma rays. Simultaneously, source windows 6 are provided on both the drill collar body 1 and the shielding assembly 5, and the source windows 6 are correspondingly positioned to the density source 3, thereby providing an emission path for gamma rays from the density source 3.

[0023] The short section shielding structure for the density measurement instrument in this embodiment effectively shields gamma rays by adding a shielding component 5 between the density source 3 and the detector, thereby improving measurement accuracy.

[0024] In one embodiment, such as Figure 2 , Figure 3 , Figure 4 As shown, the shielding assembly 5 includes a side shielding block 51, an upper shielding block 52, and a shielding cylinder 53. A first limiting groove 54 is provided on the drill collar body 1. The side shielding block 51 is tightly fitted into the first limiting groove 54, and is located between the density source 3 and the detector assembly 4. Simultaneously, the side shielding block 51 is provided with threaded holes, allowing workers to easily remove the side shielding block 51 from the first limiting groove 54 using a threaded hammer.

[0025] In one embodiment, such as Figure 2 , Figure 3 , Figure 4 As shown, the upper shielding block 52 presses against the drill collar body 1. A shielding cover plate 55 is detachably connected to the drill collar body 1 by screws. The shielding cover plate 55 is provided with a second limiting groove 56. The upper shielding block 52 is tightly inserted into the second limiting groove 56, and the shielding cover plate 55 is used to press the side shielding block 51 and the upper shielding block 52 together. The shielding cylinder 53 is assembled into the flow channel of the drill collar body by interference fit, and the upper shielding block 52 and the shielding cylinder 53 are located on both sides of the density source 3.

[0026] In this embodiment, the side shielding block 51 is cubic in shape and uses high-density shielding material, including but not limited to tungsten alloys and lead alloys, to shield gamma rays emitted from the side of the source port. The shielding cylinder 53 uses high-density shielding material, including but not limited to tungsten alloys and lead alloys, to shield gamma rays emitted from the direction of the drill collar flow channel. The upper shielding block 52 is cuboid in shape and uses high-density shielding material, including but not limited to tungsten alloys and lead alloys, to shield gamma rays.

[0027] In this embodiment, the shielding cover 55 is made of Inconel 718 material, and a tungsten carbide wear-resistant layer is laser-coated on the surface of the shielding cover 55. Firstly, it can further shield gamma rays; secondly, it can adhere to the well wall to improve the measurement effect; and thirdly, it can improve wear resistance.

[0028] In one embodiment, such as Figure 2 , Figure 3 , Figure 4 As shown, a shock-absorbing pad 57 is provided in the first limiting groove 54, and the side shielding block 51 is in close contact with the shock-absorbing pad 57 to achieve buffering and shock absorption of the side shielding block 51, thereby protecting the side shielding block 51. In this embodiment, the side shielding block 51 is made of shock-absorbing materials such as silicone foam and is placed below the side shielding block 51 to achieve shock absorption and protection.

[0029] In one embodiment, such as Figure 2 , Figure 3 As shown, the drill collar body 1 is provided with a first source hole 61, the upper shielding block 52 is provided with a second source hole 62, and the shielding cover plate 55 is provided with a third source hole 63. The first source hole 61, the second source hole 62 and the third source hole 63 are aligned with each other and together form a source window 6.

[0030] In one embodiment, such as Figure 2 , Figure 3 As shown, the opening side of the source window 6 is inclined toward the detector assembly 4, and the inner wall of the source window 6 has a flared structure, that is, the source window 6 is inclined. The opening side of the source window 6 is close to the detector assembly 42, and the bottom side of the slot is close to the density source 3. The source window 6 is formed in the shape of a trumpet, that is, the inner diameter of the opening side of the source window 6 is larger than the inner diameter of its bottom side.

[0031] In one embodiment, such as Figure 2 , Figure 3 As shown, in order to ensure the consistency of the measurement, the source window 6 formed by the first source hole 61, the second source hole 62 and the third source hole 63 is filled with organic material, including but not limited to silicone rubber, epoxy resin, PEEK, etc.

[0032] In one embodiment, such as Figure 2 , Figure 3 , Figure 4As shown, the drill collar body 1 is provided with a release groove 7, and the first source hole 61 is located between the first limiting groove 54 and the release groove 7 to release stress.

[0033] In one embodiment, such as Figure 2 , Figure 4 , Figure 5 As shown, the detector assembly 4 includes a far detector 41 and a near detector 42. A third limiting groove 43 is provided on the drill collar body 1. The far detector 41 and the near detector 42 are tightly inserted into the third limiting groove 43 respectively. The near detector 42 is located between the far detector 41 and the shielding assembly 5.

[0034] In one embodiment, such as Figure 2 , Figure 4 , Figure 5 As shown, a detector cover plate 44 is detachably connected to the drill collar body 1 by screws, and the detector cover plate 44 is used to press the far detector 41 and the near detector 42. At the same time, the detector cover plate 44 is provided with a fourth limiting groove 45, and the far detector 41 and the near detector 42 are respectively inserted into the fourth limiting groove 45. That is, one side of the far detector 41 and the near detector 42 are respectively inserted into the third limiting groove 43, and the other side is respectively inserted into the fourth limiting groove 45, thereby improving the limiting effect.

[0035] In this embodiment, the drill collar body 1 and the detector cover plate 44 are sealed by a sealing ring. The detector cover plate 44 is made of Inconel 718 material and has a tungsten carbide wear-resistant layer laser-coated on its surface. Firstly, it can further shield gamma rays; secondly, it can adhere to the well wall to improve the measurement effect; and thirdly, it can improve wear resistance.

[0036] In addition, in order to enable gamma rays to be received, near-density detector windows and far-density detector windows are provided on the detector cover plate 44. To ensure measurement consistency and prevent mud from entering the far-density detector window, organic materials, including but not limited to silicone rubber, epoxy resin, PEEK, etc., are filled in the far-density detector window.

[0037] In one embodiment, such as Figure 2 , Figure 5 As shown, a buffer pad 46 is provided in the third limiting groove 43, and the far detector 41 and the near detector 42 are respectively in close contact with the buffer pad 46 to achieve buffering and shock absorption of the detectors, thereby protecting the detectors. In this embodiment, the buffer pad 46 is made of shock-absorbing materials such as silicone foam and is placed below the near detector 42 and the far detector 41 to achieve shock absorption and protection.

[0038] In one embodiment, such as Figure 5As shown, the drill collar body 1 is provided with a positioning post 8, and the detector cover plate 44 is provided with a positioning hole 9. The positioning post 8 is tightly inserted into the positioning hole 9, which can not only realize the installation and positioning of the detector cover plate 44, but also improve the limiting effect of the detector cover plate 44.

[0039] In one embodiment, such as Figure 5 As shown, the far detector 41 and the near detector 42 each include a shielding shell 10, a detector body 11, a shielding end cap 12, and a spring element 13. The detector body 11 is tightly inserted into the shielding shell 10, and the shielding end cap 12 is detachably connected to the opening side of the shielding shell 10 by screws. The spring element 13 is disposed between the detector body 11 and the shielding end cap 12. In this embodiment, the spring element 13 can be a spring or a rubber block to dampen the near detector 42 and the far detector 41, preventing damage to them from vibration.

[0040] It should be noted that, unless otherwise stated, the technical or scientific terms used in this invention should have the ordinary meaning as understood by one of ordinary skill in the art.

[0041] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A shielding structure for a short section used in drilling density measurement, characterized in that, include: Drill collar body(1); Mounting hole (2) is provided on the drill collar body (1); Density source (3) is detachably connected to the mounting hole (2); The detector assembly (4) is disposed on the drill collar body (1); A shielding assembly (5) is disposed on the drill collar body (1) and located between the density source (3) and the detector assembly (4) to shield gamma rays; Source window (6) is set on the drill collar body (1) and the shielding component (5) and is set in correspondence with the density source (3).

2. The shielding structure for the drilling density instrument measurement short section according to claim 1, characterized in that, The shielding component (5) includes: A side shielding block (51) is disposed on the drill collar body (1); The upper shielding block (52) is disposed on the drill collar body (1); The shielding cylinder (53) is coaxially disposed inside the drill collar body (1); The side shielding block (51) is located between the density source (3) and the detector assembly (4), and the upper shielding block (52) and the shielding cylinder (53) are located on both sides of the density source (3).

3. The shielding structure for the drilling density instrument measurement short section according to claim 2, characterized in that, The drill collar body (1) is provided with a first limiting groove (54), the side shielding block (51) is tightly inserted into the first limiting groove (54), the drill collar body (1) is detachably connected with a shielding cover plate (55), the shielding cover plate (55) is provided with a second limiting groove (56), the upper shielding block (52) is tightly inserted into the second limiting groove (56), and the shielding cover plate (55) is used to press the side shielding block (51) and the upper shielding block (52).

4. The shielding structure for the drilling density instrument measurement short section according to claim 3, characterized in that, The first limiting groove (54) is provided with a shock-absorbing pad (57), and the side shielding block (51) is in close contact with the shock-absorbing pad (57).

5. The shielding structure for the drilling density instrument measurement short section according to claim 3, characterized in that, The drill collar body (1) is provided with a first source hole (61), the upper shielding block (52) is provided with a second source hole (62), and the shielding cover plate (55) is provided with a third source hole (63). The first source hole (61), the second source hole (62) and the third source hole (63) are aligned with each other and together form the source window (6). The opening side of the source window (6) is inclined toward the detector assembly (4), and the inner wall of the source window (6) has an flared structure.

6. The shielding structure for the drilling density instrument measurement short section according to claim 5, characterized in that, The drill collar body (1) is provided with a release groove (7), and the first source hole (61) is located between the first limiting groove (54) and the release groove (7).

7. The shielding structure for the drilling density instrument measurement short section according to claim 1, characterized in that, The detector assembly (4) includes: The third limiting groove (43) is provided on the drill collar body (1); The remote detector (41) is tightly inserted into the third limiting groove (43); The near detector (42) is tightly inserted into the third limiting groove (43), and the near detector (42) is located between the far detector (41) and the shielding component (5); The detector cover (44) is detachably connected to the drill collar body (1) and is used to press the far detector (41) and the near detector (42); The fourth limiting groove (45) is provided on the detector cover plate (44), and the far detector (41) and the near detector (42) are respectively inserted into the fourth limiting groove (45).

8. The shielding structure for the drilling density instrument measurement sub according to claim 7, characterized in that, A buffer pad (46) is provided in the third limiting groove (43), and the far detector (41) and the near detector (42) are in close contact with the buffer pad (46).

9. The shielding structure for the drilling density instrument measurement short section according to claim 7, characterized in that, The drill collar body (1) is provided with a positioning post (8), and the detector cover plate (44) is provided with a positioning hole (9), and the positioning post (8) is tightly inserted into the positioning hole (9).

10. The shielding structure for the drilling density instrument measurement short section according to claim 7, characterized in that, The far detector (41) and the near detector (42) respectively include a shielding shell (10), a detector body (11), a shielding end cap (12) and an elastic member (13). The detector body (11) is tightly inserted into the shielding shell (10). The shielding end cap (12) is detachably connected to the opening side of the shielding shell (10), and the elastic member (13) is disposed between the detector body (11) and the shielding end cap (12).

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