Double-spacing integrated gamma detector and logging instrument
By designing an integrated dual-source-spacing gamma detector, the problems of volume redundancy and source-spacing inaccuracy in traditional gamma logging tools are solved, enabling high-precision measurement and improved reliability in complex wellbore environments, and providing high-quality uranium content data.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-28
- Publication Date
- 2026-04-07
AI Technical Summary
Traditional gamma logging tools use axially separated discrete detectors, which result in system complexity, volume redundancy, and source distance inaccuracy. This leads to poor adaptability in complex well structures such as small boreholes and highly deviated wells, and measurement accuracy is easily affected. Furthermore, the connections are complex and the reliability is low.
The dual-source distance integrated gamma detector adopts a spatial multiplexing architecture by integrating near-source distance probes and far-source distance probes in the housing and combining them with readout electronics modules. A shielding layer is set in the housing to fix the probe position, reduce redundant cables, and improve the detector's anti-interference capability and measurement accuracy.
It effectively reduces detector size, avoids source-to-source misalignment, improves measurement accuracy and reliability, reduces the risk of connection failures, and provides high-quality uranium content data, providing a reliable basis for resource assessment and geological analysis.
Smart Images
Figure CN224096024U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of uranium exploration logging technology, and more specifically, to a dual-source distance integrated gamma detector and logging instrument. Background Technology
[0002] Natural gamma logging is one of the key technologies for identifying formation lithology, dividing reservoirs, and conducting formation correlation. Its core lies in accurately measuring gamma rays produced by the decay of natural radionuclides in the formation through a detector. Traditional gamma logging tools generally adopt an axially separated discrete scintillator detector scheme, that is, a neutron source and two detectors, such as NaI(Tl) or BGO crystals, in combination with photomultiplier tubes, arranged at a specific interval along the instrument axis.
[0003] However, this traditional discrete detector structure has several inherent defects that severely limit the performance and reliability of logging tools, mainly in the following aspects:
[0004] 1. The instrument's length and size limit its miniaturization and adaptability. To achieve effective measurement and compensation, sufficient axial distance must be maintained between the two detectors and the neutron source, i.e., the minimum source distance difference must be met. This physical requirement directly leads to an excessively long overall length and high structural redundancy of the instrument. As exploration and development become more refined, complex well structures such as small-diameter and highly deviated wells are increasingly common. Existing logging instruments, due to their excessive length, face challenges in adaptability, operational difficulties, and even inability to be deployed into these restricted well environments.
[0005] 2. Measurement accuracy is easily affected by mechanical vibration and impact. In harsh downhole operating environments, strong vibration and impact can easily cause microscopic shifts or axial displacements in the relative positions between the neutron source and the detector. This "source-distance misalignment" phenomenon directly changes the measurement geometry of gamma rays, introducing non-negligible systematic errors, which seriously affect the accuracy of energy spectrum data and the reliability of formation evaluation results.
[0006] 3. Low system integration, complex connections and challenges to reliability: Discrete detectors and their supporting electronic modules, such as high-voltage power supplies, amplifiers, and multichannel analyzers, usually require independent packaging and a large number of interconnecting cables. This not only increases the overall complexity and manufacturing cost of the instrument, but also significantly increases the risk of failures such as connector failure and cable breakage due to the numerous downhole connection points, thus reducing the long-term operational stability of the entire logging system.
[0007] Therefore, there is an urgent need in this field for a new type of gamma logging detector solution to overcome the bottlenecks in size, accuracy and reliability caused by the aforementioned discrete structure. Utility Model Content
[0008] 1. Technical problem to be solved by the utility model
[0009] The purpose of this invention is to solve the technical problems of traditional gamma logging tools, which use axially separated discrete detectors, resulting in system complexity, volume redundancy, and source distance inaccuracy. This solution uses a mechanically rigid dual-probe gamma detector, combined with a dual-probe integrated readout electronics module to form a spatial reuse architecture and integrated packaging, thus solving the problems of volume redundancy and source distance inaccuracy of discrete detectors, effectively reducing redundant cables in the system, and improving the reliability of the detection results.
[0010] 2. Technical Solution
[0011] To achieve the above objectives, the technical solution provided by this utility model is as follows:
[0012] The first aspect of this utility model is to provide a dual-source distance integrated gamma detector, including a housing, a dual-probe assembly and a readout electronics module;
[0013] The dual-probe assembly includes a near-source probe and a far-source probe, which are fixedly spaced inside the housing and are both configured as radiation-resistant scintillation crystals connected to photoelectric converters. A central cavity is formed between the near-source probe and the far-source probe, as well as on the inner wall of the housing, and the readout electronics module is integrated within the central cavity. A shielding layer is provided on the inner wall of the housing to shield against electromagnetic interference and reduce neutron radiation damage.
[0014] Furthermore, it also includes a fixing bracket disposed inside the housing, the fixing bracket supporting and fixing the near-source distance probe and the far-source distance probe respectively, for defining the relative position between the near-source distance probe and the far-source distance probe.
[0015] Furthermore, if we define the structure connecting the near-field probe to the fixed bracket as the first end of the fixed bracket and the structure connecting the far-field probe as the second end of the fixed bracket, then:
[0016] A movable adjustment part is provided between the first end and the second end of the fixed bracket. The movable adjustment part is used to adjust the distance between the first end and the second end so that a central cavity of different size is formed between the housing and the dual probe assembly, thereby installing the readout electronics module of different size.
[0017] Furthermore, the readout electronics module includes a high-voltage circuit, a signal processing board, and a communication unit;
[0018] The high-voltage circuit is electrically connected to the dual-probe assembly, providing power and an independently adjustable bias voltage. The signal processing board is electrically connected to the high-voltage circuit and includes a preamplifier, an analog-to-digital converter, and an FPGA processor connected in sequence. It is used to acquire and process the output signals from the near-source and far-source probes in the dual-probe assembly, and to statistically analyze the count ratio and energy spectrum of characteristic gamma rays by the dual-probe assembly. The output of the photoelectric converter is connected to the input of the preamplifier, and the FPGA processor is internally configured with a pulse counting module and an energy spectrum analysis module. The communication unit is electrically connected to the signal processing board, used to upload the count ratio and energy spectrum statistically obtained from the dual-probe assembly for qualitative and quantitative analysis of the probed strata.
[0019] Furthermore, the radiation-resistant scintillation crystal is selected from CsI(Tl) crystal, Cs3Cu2I5(Tl) crystal, GSO:Ce crystal, LYSO:Ce crystal, BGO crystal, PWO crystal, BaF2 crystal, CeF3 crystal, and G-(Gd,La)2Si2O7:Ce³. + Crystals, Rb2AgBr3:Cu crystals, Cs3Cu2I5(Li / Tl) crystals, LuAG:Ce ceramic crystals, GYAGG ceramic crystals, GAGG crystals.
[0020] Furthermore, the movable adjustment part is selected from linear telescopic mechanism, screw adjustment mechanism, gear and rack mechanism, cam adjustment mechanism, linkage mechanism, eccentric wheel adjustment mechanism, and slide rail slider mechanism.
[0021] Furthermore, the communication unit is a single-cable transmission communication unit.
[0022] Furthermore, the shielding layer is a metal shielding layer.
[0023] Furthermore, the shielding layer is selected from aluminum shielding layers and copper shielding layers.
[0024] In a second aspect, this utility model provides a dual-source-distance integrated gamma logging tool, comprising a pulsed neutron source and a gamma detector, wherein the gamma detector is the dual-source-distance integrated gamma detector provided in the first aspect of this utility model.
[0025] 3. Beneficial effects
[0026] Compared with the prior art, the technical solution provided by this utility model has the following advantages:
[0027] (1) The dual-source distance integrated gamma detector provided by this utility model forms a central cavity through the shell and the near-source distance probe and far-source distance probe arranged at intervals inside it. The readout electronics module is placed in the central cavity to form a spatial multiplexing architecture, which effectively solves the problems of volume redundancy and source distance inaccuracy of discrete detectors. By efficiently integrating the detection function and signal readout function in the limited space of the shell, the overall volume and weight of the detector are greatly reduced, which is convenient for deployment in narrow or complex spaces. At the same time, the integrated structure fundamentally avoids the relative position deviation between probes caused by mechanical vibration or temperature change, ensuring the long-term stability of measurement geometry, thereby ensuring the consistency and reliability of data acquisition.
[0028] (2) The dual-source distance integrated gamma detector provided by this utility model adopts a metal shielding layer to realize the enclosed design of the space architecture of the dual probe assembly and readout electronics module, which can effectively block stray radiation and electromagnetic noise from the external environment, enabling the detector to accurately focus on the target detection signal, effectively improving the detector's anti-interference ability and reducing measurement errors; at the same time, the robust metal shielding layer provides physical protection for the internal precision components, enhances the mechanical strength and overall structural stability of the detector, thereby significantly improving the service life and field adaptability of the equipment and reducing maintenance costs.
[0029] (3) The dual-source distance integrated gamma detector provided by this utility model can more accurately remove environmental interference and reflect the true uranium element information of the strata by acquiring the gamma ray count rate under different source distances with stable source distance difference at the same time point, so that the final uranium content data is more accurate and reliable, and provides a high-quality data foundation for resource assessment and geological analysis. Attached Figure Description
[0030] Figure 1 A cross-sectional view of the gamma detector provided by this utility model.
[0031] The specific meanings of each mark in the diagram are as follows:
[0032] 101-Near-source probe; 102-Long-source probe; 103-Central cavity; 104-High voltage circuit; 105-Signal processing board; 106-Communication unit; 107-Shielding layer; 108-Housing. Detailed Implementation
[0033] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings.
[0034] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0035] The dual-source distance integrated gamma detector and logging tool disclosed in this utility model will be further described below with reference to the embodiments shown in the accompanying drawings.
[0036] This embodiment provides a dual-source distance integrated gamma detector, including a metal housing 108, a dual-probe assembly, and a readout electronics module; the housing 108 is hermetically sealed except for a reserved hole through which the signal lines of the readout electronics module pass, and is typically made of stainless steel; the dual-probe assembly includes a near-source distance probe 101 and a far-source distance probe 102, such as... Figure 1 As shown, the near-range probe 101 and the far-range probe 102 are fixedly disposed at intervals inside the housing 108, and both are radiation-resistant scintillation crystals connected to photoelectric converters; the photoelectric converters are selected as photomultiplier tubes, which are coupled to the radiation-resistant scintillation crystals. A central cavity 103 is formed between the near-range probe 101 and the far-range probe 102, and on the inner wall of the housing 108, and the readout electronics module is integrated within the central cavity 103. Optionally, the radiation-resistant scintillation crystal is selected from CsI(Tl) crystal, Cs3Cu2I5(Tl) crystal, GSO:Ce crystal, LYSO:Ce crystal, BGO crystal, PWO crystal, BaF2 crystal, CeF3 crystal, and G-(Gd,La)2Si2O7:Ce³. + Crystals, such as Rb2AgBr3:Cu crystal, Cs3Cu2I5(Li / Tl) crystal, LuAG:Ce ceramic crystal, GYAGG ceramic crystal, GAGG crystal, etc., are preferred in the embodiments, with CsI(Tl) crystal being preferred.
[0037] Compared to traditional discrete detectors, this invention significantly reduces the overall size of the detector and improves its adaptability by spatially reusing the dual-probe assembly and readout electronics module within the housing 108. Furthermore, by integrating the dual-probe assembly and readout electronics module into a single structure within the housing 108, the detector's size is further reduced while simultaneously fixing the relative positions of the near-source distance probe 101 and the far-source distance probe 102. This prevents microscopic shifts or axial movement in the relative position between the neutron source and the detector caused by vibrations and impacts during downhole operations, thus improving the detector's measurement accuracy. Consequently, when the integrated dual-source distance gamma detector is installed in the logging tool, the spacing between the near-source distance probe 101 and the far-source distance probe 102 along the logging tool's axis within the housing 108 must meet the minimum source distance difference requirement.
[0038] To further improve the detector's detection accuracy, a shielding layer 107 is applied to the inner wall of the housing 108 to shield against electromagnetic interference and reduce neutron radiation damage. Optionally, the shielding layer 107 is a metal shielding layer. A metal shielding layer not only shields against electromagnetic noise and reduces neutron radiation damage, but also provides physical protection for the dual-probe assembly and readout electronics module inside the housing 108, enhancing the detector's mechanical strength and overall structural stability, and extending the device's service life. Optionally, the shielding layer 107 is selected from aluminum or copper shielding layers; in this embodiment, an aluminum shielding layer is preferred.
[0039] In specific implementation, to avoid source distance misalignment and ensure the stability of the source distance between the near-source distance probe 101 and the far-source distance probe 102, one approach is to directly fix the near-source distance probe 101 and the far-source distance probe 102 to the inner walls of the housing 108 respectively. Another approach is to indirectly fix them to the housing 108 in other ways, such as using a bracket fixed to the housing 108 to fix the probes, thereby fixing the relative positions of the two probes.
[0040] In this embodiment, the dual-probe assembly is indirectly fixed to the housing 108 to achieve stable source distance between the near-source distance probe 101 and the far-source distance probe 102. Specifically, the integrated dual-source distance gamma detector also includes a fixed bracket disposed inside the housing 108. The fixed bracket supports and is fixed to the near-source distance probe 101 and the far-source distance probe 102 respectively, and is used to define the relative position between the near-source distance probe 101 and the far-source distance probe 102. In this embodiment, the fixed bracket is a titanium alloy bracket to rigidly fix the near-source distance probe 101 and the far-source distance probe 102, and control the source distance error within the industry allowable range. The mechanical rigid fixation ensures that the source distance between the near-source distance probe 101 and the far-source distance probe 102 remains unchanged, ensuring accurate measurement results.
[0041] To accommodate complex well structures such as small-diameter wells and highly deviated wells, gamma logging tools come in various sizes. The size of the gamma logging tool can be adjusted by changing the size of the internal detector. For example, while ensuring that the minimum source distance difference requirement is met between the near-source distance probe 101 and the far-source distance probe 102, an adjustable mounting bracket can be designed to accommodate housings 108 of different sizes, thereby forming central cavities 103 of different sizes to install readout electronics modules of different sizes, thus meeting the requirements of logging tools of different sizes.
[0042] Specifically, defining the structure connecting the near-range probe 101 to the fixed bracket as the first end of the fixed bracket and the structure connecting the far-range probe 102 as the second end of the fixed bracket, then: a movable adjustment part is provided between the first end and the second end of the fixed bracket. The movable adjustment part is used to adjust the distance between the first end and the second end, so that a central cavity 103 of different sizes is formed between the housing 108 and the dual-probe assembly, thereby installing the readout electronics modules of different sizes. Optionally, the movable adjustment part is selected from a linear telescopic mechanism, a screw adjustment mechanism, a gear and rack mechanism, a cam adjustment mechanism, a linkage mechanism, an eccentric wheel adjustment mechanism, and a slide rail slider mechanism. For example, when the movable adjustment part is selected as a linear telescopic mechanism, the linear telescopic mechanism includes a telescopic part composed of several telescopic sections sequentially fitted together and at least one limiting post. Each telescopic section is provided with a limiting hole at a corresponding position, and the limiting hole and the limiting post are adapted to engage. The first end and the second end are respectively located at both ends of the telescopic part in the telescopic direction. The telescopic section is stretched to the corresponding position of the limiting hole and engaged by the limiting post to complete the stretching. The distance between the first end and the second end is adjusted, that is, after cooperating with the housing 108, a central cavity 103 of different sizes is formed.
[0043] Further integration Figure 1As shown, the readout electronics module includes a high-voltage circuit 104, a signal processing board 105, and a communication unit. The high-voltage circuit 104 is electrically connected to the dual-probe assembly and is used to power the dual-probe assembly, providing an independently adjustable bias voltage. In this embodiment, the high-voltage circuit 104 uses a miniature DC-DC module with continuously adjustable output voltage. The signal processing board 105 is electrically connected to the high-voltage circuit 104 and includes a preamplifier, an analog-to-digital converter, and an FPGA processor connected in sequence. It is used to acquire and process the output signals of the near-source probe 101 and the far-source probe 102 in the dual-probe assembly, and to count the count ratio of characteristic gamma rays by the dual-probe assembly. The output terminal of the photoelectric converter is connected to the input terminal of the preamplifier, and the FPGA processor is configured with pulse counting and time spectrum analysis functions. The communication unit 106 is electrically connected to the signal processing board 105 and is used to upload the count ratio counted by the dual-probe assembly. In this embodiment, the communication unit 106 is configured as a single-cable transmission communication unit, that is, data is transmitted through a single cable to reduce connection points.
[0044] Compared to traditional discrete gamma detectors with their separate electronics modules, this invention only requires a single readout electronics module. It uses an analog-to-digital converter and an FPGA processor for signal processing and transmits data via a single cable, greatly reducing redundant cables and lowering the risk of connection failures.
[0045] Another embodiment of this utility model proposes a dual-source-spacing integrated gamma logging tool, including a pulsed neutron source and a gamma detector. The gamma detector is the dual-source-spacing integrated gamma detector disclosed in the above embodiment. During installation, the pulsed neutron source and the gamma detector are sequentially fixed inside the logging tool housing. In operation, the pulsed neutron source is first activated, exciting formation elements to generate characteristic gamma rays. Then, the near-source-spacing probe 101 and the far-source-spacing probe 102 simultaneously acquire energy spectra. The readout electronics module processes the data signals in real time, determines the count ratio of characteristic gamma rays, and uploads this count ratio to the surface logging computer via the communication unit 106. Finally, the uranium content in the formation is inverted by combining the calibration model and other data.
[0046] The dual-source-distance integrated gamma detector and logging tool disclosed in this utility model, in the first aspect, solves the technical problems of volume redundancy and source-distance inaccuracy of traditional discrete detectors by forming a spatial multiplexing architecture through the housing 108, the dual-probe assembly and the readout electronics module, thus maintaining fixed geometric conditions for gamma ray measurement; in the second aspect, the shielding layer set on the inner wall of the housing 108 improves the detector's anti-interference capability and service life; furthermore, based on the working principle of synchronous data acquisition by the near-source-distance probe 101 and the far-source-distance probe 102, the structural improvements and effects of the first and second aspects are combined to achieve the technical effect of optimizing the calculation accuracy of uranium content when the detector is used for uranium content detection in the formation, thereby improving the reliability of formation evaluation results.
[0047] The above description is illustrative of the present invention and its embodiments. This description is not restrictive and is merely one embodiment of the present invention, and is not actually limited thereto. Therefore, if those skilled in the art, inspired by this description, design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.
Claims
1. A dual-source integrated gamma detector, characterized in that, Includes housing, dual-probe assembly, and readout electronics module; The dual-probe assembly includes a near-source probe and a far-source probe, which are fixedly spaced inside the housing and are both configured as radiation-resistant scintillation crystals connected to photoelectric converters. A central cavity is formed between the near-source probe and the far-source probe, as well as on the inner wall of the housing, and the readout electronics module is integrated within the central cavity. A shielding layer is provided on the inner wall of the housing to shield against electromagnetic interference and reduce neutron radiation damage.
2. The dual-source integrated gamma detector according to claim 1, characterized in that, It also includes a fixing bracket disposed inside the housing, which supports and is fixed to the near-source distance probe and the far-source distance probe respectively, and is used to define the relative position between the near-source distance probe and the far-source distance probe.
3. The dual-source integrated gamma detector according to claim 2, characterized in that, Define the structure connecting the near-field probe to the fixed bracket as the first end of the fixed bracket, and the structure connecting the far-field probe as the second end of the fixed bracket, then: A movable adjustment part is provided between the first end and the second end of the fixed bracket. The movable adjustment part is used to adjust the distance between the first end and the second end so that a central cavity of different size is formed between the housing and the dual probe assembly, thereby installing the readout electronics module of different size.
4. The dual-source integrated gamma detector according to claim 1, characterized in that, The readout electronics module includes a high-voltage circuit, a signal processing board, and a communication unit; The high-voltage circuit is electrically connected to the dual-probe assembly, providing power and an independently adjustable bias voltage. The signal processing board is electrically connected to the high-voltage circuit and includes a preamplifier, an analog-to-digital converter, and an FPGA processor connected in sequence. It is used to acquire and process the output signals from the near-source and far-source probes in the dual-probe assembly, and to statistically analyze the count ratio and energy spectrum of characteristic gamma rays detected by the dual-probe assembly. The output of the photoelectric converter is connected to the input of the preamplifier, and the FPGA processor is internally configured with a pulse counting module and an energy spectrum analysis module. The communication unit is electrically connected to the signal processing board and is used to upload the count ratio and energy spectrum statistically obtained from the dual-probe assembly for qualitative and quantitative analysis of the detected strata.
5. The dual-source integrated gamma detector according to claim 1, characterized in that, The radiation-resistant scintillation crystals are selected from CsI(Tl) crystals, Cs3Cu2I5(Tl) crystals, GSO:Ce crystals, LYSO:Ce crystals, BGO crystals, PWO crystals, BaF2 crystals, CeF3 crystals, and G-(Gd,La)2Si2O7:Ce³. + Crystals, Rb2AgBr3:Cu crystals, Cs3Cu2I5(Li / Tl) crystals, LuAG:Ce ceramic crystals, GYAGG ceramic crystals, GAGG crystals.
6. The dual-source integrated gamma detector according to claim 3, characterized in that, The movable adjustment part is selected from linear telescopic mechanism, screw adjustment mechanism, gear and rack mechanism, cam adjustment mechanism, linkage mechanism, eccentric wheel adjustment mechanism, and slide rail slider mechanism.
7. The dual-source integrated gamma detector according to claim 4, characterized in that, The communication unit is a single-cable transmission communication unit.
8. The dual-source integrated gamma detector according to claim 1, characterized in that, The shielding layer is a metal shielding layer.
9. The dual-source integrated gamma detector according to claim 1, characterized in that, The shielding layer is selected from aluminum shielding layer and copper shielding layer.
10. A dual-source integrated gamma logging tool, comprising a pulsed neutron source and a gamma detector, characterized in that, The gamma detector is the dual-source integrated gamma detector as described in any one of claims 1-9.