A neutron well logging device with variable source distance

Abstract

The present invention relates to a variable source distance neutron logging device, comprising a neutron generator assembly, a collection assembly and a transmission assembly; the collection assembly has a first installation cavity and a second installation cavity that are interconnected, a near detector assembly and a far detector assembly are respectively arranged in the first installation cavity and the second installation cavity, the end of the near detector assembly is connected to the first installation cavity through a first spacing adjustment mechanism, and the end of the far detector assembly is connected to the second installation cavity through a second spacing adjustment mechanism; the near detector assembly and the far detector assembly are both electrically connected to the transmission assembly. The present invention can not only match and adapt to a variety of neutron sources, but also study the influence of different source distance schemes on the measurement accuracy of reservoir porosity or density.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum well logging, in particular to a variable source distance neutron well logging device. Background Art

[0002] Oil logging uses high-precision technologies such as sound, electricity, radioactivity, and nuclear magnetic resonance to measure underground formation information in order to discover oil and gas reservoirs and evaluate oil and gas reserves. It plays an important role in oil and gas exploration and production. According to the measurement mechanism, logging methods can be divided into electrical logging, acoustic logging, radioactive logging, and other logging methods.

[0003] Among many logging methods, neutron porosity logging and density logging are the most commonly used nuclear logging methods. At present, most domestic neutron logging instruments use Am-Be isotope chemical neutron sources, and most density logging instruments use Cs-137 isotope chemical gamma sources. During neutron porosity logging, the neutron source continuously emits high-energy neutrons to the surrounding formations. The emitted neutrons collide with the nuclei of elements in the formation to produce secondary neutrons carrying formation information. These secondary neutrons are detected and analyzed to obtain porosity data. During density logging, the gamma-ray source can emit gamma rays of fixed intensity to the surrounding formations. When the gamma rays pass through the formation, the Compton effect occurs, generating scattered gamma rays. The density of the lithology can be determined by detecting and analyzing these gamma rays. In addition, current logging instruments all use a certain fixed neutron source or gamma source, and their source distances are also fixed.

[0004] With the development of HSE (Health, Safety, and Environmental Protection) concepts, people are paying more and more attention to the hazards of radioactivity, and isotope chemical source instruments will gradually fade out of the market. The development of DD / DT controlled neutron source neutron logging instruments is imperative.

[0005] Therefore, those skilled in the art are committed to developing a variable source distance neutron logging device, which can not only match and adapt to a variety of neutron sources, but also study the influence of different source distance schemes on the measurement accuracy of reservoir porosity or density. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a variable source distance neutron logging device, which can not only match and adapt to a variety of neutron sources, but also study the influence of different source distance schemes on the measurement accuracy of reservoir porosity and density.

[0007] The technical solution of the present invention to solve the above technical problems is as follows: a variable source distance neutron logging device, comprising a neutron generator component, a collection component and a transmission component;

[0008] The acquisition assembly has a first installation cavity and a second installation cavity that are interconnected, wherein a near detector assembly and a far detector assembly are respectively disposed in the first installation cavity and the second installation cavity, wherein an end of the near detector assembly is connected to the first installation cavity via a first spacing adjustment mechanism, and an end of the far detector assembly is connected to the second installation cavity via a second spacing adjustment mechanism;

[0009] The near detector assembly and the far detector assembly are both electrically connected to the transmission assembly.

[0010] The beneficial effects of the present invention are as follows: the near detector assembly and the far detector assembly can be moved in the first installation cavity and the second installation cavity respectively, and different source distance combinations can be formed. Not only can different source distances be used to match Am-Be sources, DD sources and DT sources, but also can be used to study the influence of different source distance schemes on the measurement accuracy of reservoir porosity and density when a certain fixed type of neutron source is used, thereby determining the optimal source distance.

[0011] Based on the above technical solution, the present invention can also be improved as follows.

[0012] Further, the neutron generator assembly has a first avoidance hole for movement of the near detector assembly, and the transmission assembly has a second avoidance hole for movement of the far detector assembly.

[0013] The beneficial effect of adopting the above further solution is that the first avoidance hole and the second avoidance hole provide sufficient avoidance space for the near detector assembly and the far detector assembly to move, thereby achieving large distance adjustment.

[0014] Furthermore, the near detector assembly includes a near detector body, the near detector body is arranged in a near detector housing, and a near detector end cap is also installed at the end of the near detector housing.

[0015] The beneficial effect of adopting the above further solution is that the near detector outer cover and the near detector end cover are not only beneficial to protecting the near detector body, but also beneficial to the distance adjustment.

[0016] Furthermore, the remote detector assembly includes a remote detector body, the remote detector body is arranged in a remote detector jacket, and a remote detector end cap is also installed at the end of the remote detector jacket.

[0017] The beneficial effect of adopting the above further solution is that the remote detector jacket and the remote detector end cover are not only beneficial to protecting the remote detector body, but also beneficial to the distance adjustment.

[0018] Further, the first spacing adjustment mechanism includes a first external thread provided on the outer casing of the near detector, and a second internal thread matching the first external thread is provided inside the first installation cavity;

[0019] The first external thread is also provided with a first scale bar.

[0020] The beneficial effect of adopting the above further solution is that the position of the near detector assembly in the first installation cavity can be adjusted by rotating the thread, and the moving distance of the near detector assembly can be accurately adjusted by the first scale bar to achieve stepless adjustment.

[0021] Further, the second spacing adjustment mechanism includes a second external thread provided on the outer sleeve of the remote detector, and a fourth internal thread matching with the second external thread is provided inside the second installation cavity;

[0022] The second external thread is also provided with a second scale bar.

[0023] The beneficial effect of adopting the above further solution is that the position adjustment of the remote detector assembly in the second installation cavity can be achieved by rotating the thread, and the moving distance of the remote detector assembly can be accurately adjusted by the second scale bar.

[0024] Further, the first spacing adjustment mechanism comprises a first slide groove provided on the near detector housing, a first slider which is in gap fit with the first slide groove is provided inside the first installation cavity, and a first scale bar is further provided on the first slide groove or the first slider;

[0025] The second spacing adjustment mechanism includes a second slider disposed on the outer casing of the remote detector, a second slide groove matched with the second slider is disposed inside the second mounting cavity, and a second scale bar is also disposed on the second slider or the second slide groove.

[0026] The beneficial effect of adopting the above further solution is that the detector can be moved along the installation cavity through the cooperation between the slider and the slide groove to adjust the position of the detector, and the moving distance of the detector can be accurately adjusted through the scale bar.

[0027] Furthermore, a wiring hole is provided between the first installation cavity and the second installation cavity, a connecting wire is provided in the wiring hole and is respectively connected to the near detector body and the far detector body, the other end of the connecting wire is connected to the transmission component, and the transmission component is also connected to the control device.

[0028] The beneficial effect of adopting the above further solution is that the wiring holes are conducive to the distribution of connecting wires and improve the space utilization of the acquisition component.

[0029] Furthermore, wire grooves for arranging the connecting wires are also provided on the outer side walls of the collection component and the transmission component.

[0030] The beneficial effect of adopting the above further solution is that the wire trough is conducive to the arrangement of connecting wires. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of a specific embodiment of the present invention;

[0032] Figure 2 For the present invention Figure 1 AA cross-sectional structure diagram;

[0033] Figure 3 For the present invention Figure 1 AA cross-sectional structure diagram;

[0034] Figure 4 The figure is a schematic diagram of the structure of a collection component according to a specific embodiment of the present invention.

[0035] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0036] 100, neutron generator assembly; 200, collection assembly; 300, transmission assembly;

[0037] 101. The first avoidance hole;

[0038] 201, first installation cavity; 202, second installation cavity;

[0039] 210, near detector assembly; 211, near detector body; 212, near detector jacket; 213, near detector end cover; 217, first external thread; 218, first internal thread; 219, second internal thread;

[0040] 220, remote detector assembly; 221, remote detector body; 222, remote detector jacket; 223, remote detector end cover; 225, second external thread; 226, third internal thread; 227, fourth internal thread;

[0041] 230, first scale bar; 240, second scale bar; 250, wiring hole; 251, wire slot;

[0042] 301. The second avoidance hole. DETAILED DESCRIPTION

[0043] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0044] In the description of the present invention, it is necessary to understand that the terms "center", "length", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "inside", "outside", "peripheral", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred system or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0045] In the description of the present invention, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0046] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, a variable source distance neutron logging device comprises a neutron generator assembly 100, a collection assembly 200 and a transmission assembly 300; the collection assembly 200 comprises a first installation cavity 201 and a second installation cavity 202 which are connected to each other, a near detector assembly 210 and a far detector assembly 220 are respectively arranged in the first installation cavity 201 and the second installation cavity 202, an end of the near detector assembly 210 is connected to the first installation cavity 201 via a first distance adjustment mechanism, and an end of the far detector assembly 220 is connected to the second installation cavity 202 via a second distance adjustment mechanism;

[0048] Both the near detector assembly 210 and the far detector assembly 220 are electrically connected to the transmission assembly 300 .

[0049] In the present invention, the near detector assembly 210 and the far detector assembly 220 can be moved in the first installation cavity 201 and the second installation cavity 202 respectively, and different source distance combinations can be formed. Not only can different source distances be used to match Am-Be sources, DD sources and DT sources, but they can also be used to study the effects of different source distance schemes on the measurement accuracy of reservoir porosity and density when a fixed type of neutron source is used, thereby determining the optimal source distance.

[0050] like Figure 1 , Figure 2 and Figure 3 As shown, in some embodiments, the neutron generator assembly 100 provides a neutron source for a variable source distance neutron logging instrument, which may be an Am-Be source, a DD source, or a DT source. The neutron generator assembly 100 has a first avoidance hole 101 for movement of the near detector assembly 210, and the transmission assembly 300 has a second avoidance hole 301 for movement of the far detector assembly 220. The first avoidance hole 101 and the second avoidance hole 301 are respectively used to provide sufficient avoidance space for the near detector assembly 210 and the far detector assembly 220 when adjusting the distance, thereby achieving large distance adjustment.

[0051] In a specific embodiment, the near detector assembly 210 includes a near detector body 211. The near detector body 211 can adopt a He3 tube thermal neutron detector. When the He3 tube thermal neutron detector is adopted, it is mainly used as a neutron porosity instrument to study the influence of different source distance schemes on the reservoir porosity measurement accuracy. In another embodiment, the near detector body 211 can also adopt a NaI detector, a LaBr3 detector or a BGO detector. When the NaI detector, the LaBr3 detector or the BGO detector is adopted, it is mainly used as a density logging instrument to study the influence of different source distance schemes on the reservoir density measurement accuracy. Different near detector bodies 211 are selected according to different needs to meet the versatility of the logging device. The near detector body 211 is arranged in a near detector jacket 212, and a near detector end cap 213 is also installed at the end of the near detector jacket 212.

[0052] The remote detector assembly 220 includes a remote detector body 221. The remote detector body 221 may also be made of He 3 The remote detector body 221 is arranged in the remote detector jacket 222, and the remote detector end cover 223 is also installed at the end of the remote detector jacket 222.

[0053] like Figure 1 , Figure 2 and Figure 3As shown, in some embodiments, the first spacing adjustment mechanism includes a first external thread 217 provided on the near detector housing 212. In the embodiment, in order to facilitate the connection between the neutron generator assembly 100 and the near detector assembly 210, the side wall of the first avoidance hole 101 is provided with a first internal thread 218 that matches the first external thread 217. It is also possible to provide mutually connected fasteners on the neutron generator assembly 100 and the collection assembly 200, so as to connect the neutron generator assembly 100 with the collection assembly 200. A second internal thread 219 that matches the first external thread 217 is provided inside the first installation cavity 201, and a first scale bar 230 is also provided on the first external thread 217. When adjusting, the near detector housing 212 is rotated to move the near detector assembly 210 in the first installation cavity 201, and the moving distance is determined by the first scale bar 230 to achieve stepless adjustment, thereby forming different source distance combinations.

[0054] Similarly, the second spacing adjustment mechanism includes a second external thread 225 provided on the remote detector housing 222. In the embodiment, in order to facilitate the connection between the transmission component 300 and the remote detector component 220, a third internal thread 226 cooperating with the second external thread 225 is provided on the side wall of the second avoidance hole 301. Interconnected fasteners can also be provided on the transmission component 300 and the collection component 200 to connect the transmission component 300 with the collection component 200. A fourth internal thread 227 cooperating with the second external thread 225 is provided inside the second installation cavity 202, and a second scale bar 240 is also provided on the second external thread 225. When adjusting, the remote detector housing 222 is rotated to move the remote detector component 220 in the second installation cavity 202, and the moving distance is determined by the second scale bar 240 to achieve stepless adjustment, thereby forming different source distance combinations.

[0055] In another embodiment, the first spacing adjustment mechanism includes a first slide groove provided on the near detector cover 212, a first slider that matches the first slide groove gap is provided inside the first installation cavity 201, and a first scale bar is further provided on the first slide groove or the first slider. During the adjustment process, the near detector cover 212 is pulled to move the first slide groove along the first slider, and the moving distance of the near detector cover 212 is determined by the first scale bar, thereby adjusting the near detector assembly 210 to a suitable position.

[0056] Similarly, the second spacing adjustment mechanism includes a second slider disposed on the remote detector cover 222, a second slide groove cooperating with the second slider is disposed inside the second mounting cavity 202, and a second scale bar is also disposed on the second slider or the second slide groove. During the adjustment process, the remote detector cover 222 is pulled to move the first slider along the first slide groove, and the moving distance of the remote detector cover 222 is determined by the second scale bar, thereby adjusting the remote detector assembly 220 to a suitable position.

[0057] The first spacing adjustment mechanism and the second spacing adjustment mechanism are selected according to actual conditions and are not limited here.

[0058] like Figure 1 and Figure 2 As shown, a wiring hole 250 is provided between the first installation cavity 201 and the second installation cavity 202, and the wiring hole 250 is also provided on the side of the acquisition component 200. The connecting wire is provided in the wiring hole 250 and is respectively connected to the near detector body 211 and the far detector body 221. The other end of the connecting wire is connected to the transmission component 300. The connecting wire transmits the signals of the near detector body 211 and the far detector body 221 to the transmission component 300. The transmission component 300 is also connected to the control device. The transmission component 300 and the control device can be connected by wire or wirelessly. A wire groove 251 for setting the connecting wire is also provided on the outer wall of the acquisition component 200 and the transmission component 300. The wire groove 251 is used to arrange the connecting wire.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A variable source distance neutron logging device, characterized in that: It comprises a neutron generator component (100), a collection component (200) and a transmission component (300); The acquisition assembly (200) comprises a first installation cavity (201) and a second installation cavity (202) which are interconnected, wherein a near detector assembly (210) and a far detector assembly (220) are respectively arranged in the first installation cavity (201) and the second installation cavity (202), wherein an end of the near detector assembly (210) is connected to the first installation cavity (201) via a first spacing adjustment mechanism, and an end of the far detector assembly (220) is connected to the second installation cavity (202) via a second spacing adjustment mechanism; The near detector assembly (210) and the far detector assembly (220) are both electrically connected to the transmission assembly (300); The neutron generator assembly (100) has a first avoidance hole (101) for the movement of the near detector assembly (210), and the transmission assembly (300) has a second avoidance hole (301) for the movement of the far detector assembly (220); The near detector assembly (210) comprises a near detector body (211), wherein the near detector body (211) is arranged in a near detector jacket (212), and a near detector end cap (213) is also installed at the end of the near detector jacket (212); The remote detector assembly (220) comprises a remote detector body (221), wherein the remote detector body (221) is arranged in a remote detector jacket (222), and a remote detector end cap (223) is also installed at the end of the remote detector jacket (222); The first spacing adjustment mechanism comprises a first external thread (217) arranged on the near detector housing (212), and a second internal thread (219) matching with the first external thread (217) is arranged inside the first installation cavity (201); The first external thread (217) is also provided with a first scale bar (230); The second spacing adjustment mechanism comprises a second external thread (225) arranged on the remote detector housing (222), and a fourth internal thread (227) matching with the second external thread (225) is arranged inside the second installation cavity (202); The second external thread (225) is also provided with a second scale bar (240); A wiring hole (250) is provided between the first installation cavity (201) and the second installation cavity (202); a connecting wire is provided in the wiring hole (250) and is respectively connected to the near detector body (211) and the far detector body (221); the other end of the connecting wire is connected to the transmission component (300); and the transmission component (300) is also connected to a control device; The outer side walls of the collection component (200) and the transmission component (300) are also provided with wire grooves (251) for arranging the connecting wires.

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