Controllable neutron and gamma generating device for nuclear logging

Abstract

The invention discloses a controllable neutron and gamma generation device for nuclear logging, which can control a controllable neutron generation module to generate neutrons through a control instruction issued by an external upper computer according to logging requirements, and can generate neutrons, gamma and a neutron and gamma mixed field by controlling a LiH moderator, a first neutron absorber, a second neutron absorber and a gamma absorber. Compared with traditional natural source well logging, the method improves the radiation safety level of the nuclear well logging industry while improving the well logging efficiency, and reduces the radiation dose of workers.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear well logging, and more specifically, relates to a controllable neutron and gamma generating device for nuclear well logging. Background Art

[0002] At present, the main types of petroleum logging include electrical logging, acoustic logging, production logging and nuclear logging. Among them, nuclear logging has many types, which are mainly divided into three categories: neutron logging, gamma logging and nuclear magnetic resonance logging. Commonly used nuclear logging radiation sources include americium-beryllium neutron source, radionuclide natural gamma source, and controlled neutron source.

[0003] Americium-beryllium neutron sources and radionuclide gamma sources are natural sources. The storage, transportation and production operations of the sources require high radiation protection, which poses a great radiation safety hazard to the workers. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a controllable neutron and gamma generator for nuclear logging, which can replace the natural sources currently used in nuclear logging in the petroleum industry, effectively improve the radiation safety level of the nuclear logging industry, and reduce the radiation dose of workers.

[0005] To achieve the above-mentioned purpose of the invention, the present invention provides a controllable neutron and gamma generating device for nuclear well logging, characterized in that it comprises: a communication and control module, a controllable neutron generating module, a driving component, a LiH moderator, a neutron absorber 1, a neutron absorber 2, a gamma absorber, a driving connecting rod, and a communication and control line;

[0006] The control instructions are sent to the communication and control module through an external host computer. After the communication and control module parses the relevant instructions, it controls the entire device to generate fast neutrons or specific energy gamma rays or intensity controllable gamma rays or a mixed source of neutrons and gamma rays used in nuclear logging.

[0007] The object of the invention of the present invention is achieved in this way:

[0008] The invention discloses a controllable neutron and gamma generating device for nuclear well logging. According to the well logging requirement, a controllable neutron generating module can be controlled to generate neutrons by sending control instructions through an external host computer, and neutrons, gammas, and a neutron and gamma mixed field can be generated by controlling a LiH moderator, a first neutron absorber, a second neutron absorber, and a gamma absorber. Compared with the traditional natural source well logging, the method improves the well logging efficiency and the radiation safety level of the nuclear well logging industry, and reduces the radiation dose of the workers.

[0009] At the same time, the controllable neutron and gamma generator for nuclear well logging of the present invention also has the following beneficial effects:

[0010] (1) The present invention can replace the natural americium-beryllium neutron source and natural gamma source currently used in nuclear well logging in the petroleum industry. Eliminating the natural americium-beryllium neutron source and natural gamma source used in nuclear well logging can simplify the shielding, transportation, and management procedures of the radioactive source and improve economic efficiency; at the same time, it can improve the radiation safety level of the nuclear well logging industry and reduce the radiation dose of workers;

[0011] (2) The present invention provides a controllable generation scheme of neutron, gamma, and neutron and gamma mixed fields. In the actual oil well logging process, different types of rays can be quickly generated according to the logging requirements without interrupting the logging process to replace the radiation source, which greatly improves the logging efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of a controllable neutron and gamma generator for nuclear well logging according to the present invention;

[0013] Figure 2 It is a schematic diagram of the neutron production mode;

[0014] Figure 3 This is a schematic diagram of the neutron and gamma mixed source generation mode. DETAILED DESCRIPTION

[0015] The specific implementation of the present invention is described below in conjunction with the accompanying drawings so that those skilled in the art can better understand the present invention. It should be noted that in the following description, when the detailed description of known functions and designs may dilute the main content of the present invention, these descriptions will be omitted here.

[0016] Example

[0017] Figure 1 This is a structural diagram of a controllable neutron and gamma generating device for nuclear well logging according to the present invention.

[0018] In this embodiment, if Figure 1 As shown, the present invention is a controllable neutron and γ generating device for nuclear well logging, comprising: a communication and control module 1, a controllable neutron generating module 2, a driving component 3, a LiH moderator 4, a neutron absorber 1 5, a neutron absorber 2 6, a γ absorber 7, a driving connecting rod 8, and a communication and control line 9;

[0019] The control instructions issued by the external host computer are transmitted to the communication and control module 1 through the communication and control line 9. After the communication and control module 1 parses the relevant instructions, it controls the entire device to generate fast neutrons or specific energy gamma rays or intensity controllable gamma rays or a mixed source of neutrons and gamma rays for nuclear logging.

[0020] Next, we will explain in detail the process of generating fast neutrons or specific energy gamma rays or intensity controllable gamma rays or mixed sources of neutrons and gamma rays for nuclear logging:

[0021] (1) The specific process of fast neutron generation is as follows: the external host computer sends a control instruction to the communication and control module 1. After the communication and control module 1 analyzes the relevant instructions, the control driving component 3 drives the connecting rod 8 to withdraw the LiH moderator 4, the neutron absorber 1 5, the neutron absorber 2 6, and the γ absorber 7 to the storage position, such as Figure 2 As shown; then the communication and control module 1 controls the controllable neutron generation module 2 to generate fast neutrons for logging.

[0022] (2) The specific process of generating gamma rays of specific energy is as follows: a control instruction is sent to the communication and control module 1 by an external host computer. After the communication and control module 1 analyzes the relevant instruction, the control driving component 3 drives the connecting rod 8 to lift the LiH moderator 4 from the storage position to the working position. In this embodiment, the storage position is that the upper ends of the LiH moderator 4, the neutron absorber 1 5, the neutron absorber 2 6, and the gamma absorber 7 are flush with the lower end of the controllable neutron generating module 2; the working position is that the upper ends of the LiH moderator 4, the neutron absorber 1 5, the neutron absorber 2 6, and the gamma absorber 7 exceed the lower end of the controllable neutron generating module 2;

[0023] Then, the neutron absorber 1 5 is lifted from the storage position to the working position by driving the connecting rod 8; then the communication and control module 1 controls the controllable neutron generation module 2 to generate fast neutrons for logging; the fast neutrons are then moderated by the LiH moderator to become thermal neutrons, and the thermal neutrons undergo neutron capture reactions with the neutron absorber 1 5 or the neutron absorber 2 6 to generate gamma rays of specific energy. In this embodiment, in addition to the neutron absorber 1 5 and the neutron absorber 2 6, gamma rays of different energies can also be obtained by using different neutron absorbers.

[0024] (3) The specific process of generating intensity-controlled gamma rays is as follows: the control instruction is sent to the communication and control module 1 by the external host computer. After the communication and control module 1 analyzes the relevant instruction, the control driving component 3 is controlled to lift the LiH moderator 4 from the storage position to the working position by driving the connecting rod 8, and then the neutron absorber 1 5 is lifted from the storage position to the working position by driving the connecting rod 8, and then the gamma absorber 7 is lifted from the storage position to the working position by driving the connecting rod 8, and finally the controllable neutron generating module 2 is controlled by the communication and control module 1 to generate fast neutrons for logging; the fast neutrons are slowed down into thermal neutrons by the LiH moderator, and the thermal neutrons react with the neutron absorber 1 5 or the neutron absorber 2 6 to generate gamma rays of specific energy; the gamma rays are attenuated in intensity after passing through the gamma absorber 7, and gamma rays with controllable intensity are obtained. In this embodiment, the gamma absorber 7 is a multi-layer structure, and the gamma ray intensity can be controlled by adjusting the number of layers of the gamma absorber 7.

[0025] (4) The specific generation process of the neutron and gamma-ray mixed source is as follows: a control instruction is sent to the communication and control module 1 through an external host computer. After the communication and control module 1 analyzes the relevant instructions, the control driving component 3 drives the connecting rod 8 to lift the LiH moderator 4 and the neutron absorber 1 5 from the storage position to the working position; and then the controllable neutron generating module 2 is controlled by the communication and control module 1 to generate fast neutrons for logging, wherein some fast neutrons directly enter the formation after being generated, and the other part of the fast neutrons are slowed down by the LiH moderator to become thermal neutrons, and the thermal neutrons undergo neutron capture reaction with the neutron absorber 1 5 or the neutron absorber 2 6 to generate gamma rays of specific energy.

[0026] Although the above describes the illustrative specific embodiments of the present invention to facilitate those skilled in the art to understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A controllable neutron and gamma generator for nuclear well logging, characterized in that: include: Communication and control module, controllable neutron generation module, drive components, LiH moderator, neutron absorber 1, neutron absorber 2, gamma absorber, drive connecting rod, communication and control lines; The control instructions are sent to the communication and control module through an external host computer. After the communication and control module parses the relevant instructions, it controls the entire device to generate fast neutrons or specific energy gamma rays or intensity controllable gamma rays or a mixed source of neutrons and gamma rays used in nuclear logging.

2. A controllable neutron and gamma generator for nuclear well logging according to claim 1, characterized in that: The specific process of generating fast neutrons is as follows: an external host computer sends a control instruction to the communication and control module, and after the communication and control module parses the relevant instruction, the control driving component withdraws the LiH moderator, the neutron absorber 1, the neutron absorber 2, and the gamma absorber to the storage position through the driving connecting rod, and then the communication and control module controls the controllable neutron generating module to generate fast neutrons for logging.

3. The controllable neutron and gamma generator for nuclear well logging according to claim 1, characterized in that: The specific generation process of the gamma ray of specific energy is as follows: a control instruction is sent to the communication and control module by an external host computer; after the communication and control module parses the relevant instruction, the control driving component is controlled to lift the LiH moderator from the storage position to the working position by driving the connecting rod, and then the neutron absorber 1 is lifted from the storage position to the working position by driving the connecting rod; then the communication and control module controls the controllable neutron generating module to generate fast neutrons for logging; the fast neutrons are then slowed down by the LiH moderator to become thermal neutrons, and the thermal neutrons undergo neutron capture reaction with the neutron absorber 1 or the neutron absorber 2 to generate gamma ray of specific energy.

4. A controllable neutron and gamma generator for nuclear well logging according to claim 1, characterized in that: The specific generation process of the intensity-controllable gamma ray is as follows: a control instruction is sent to the communication and control module by an external host computer; after the communication and control module parses the relevant instruction, the driving component is controlled to lift the LiH moderator from the storage position to the working position by the driving connecting rod, and then the neutron absorber 1 is lifted from the storage position to the working position by the driving connecting rod, and then the gamma absorber is lifted from the storage position to the working position by the driving connecting rod, and finally the controllable neutron generation module is controlled by the communication and control module to generate fast neutrons for logging; the fast neutrons are slowed down into thermal neutrons by the LiH moderator, and the thermal neutrons undergo neutron capture reaction with the neutron absorber 1 or the neutron absorber 2 to generate gamma rays with specific energy; the gamma rays are attenuated in intensity after passing through the gamma absorber, and gamma rays with controllable intensity are obtained.

5. The controllable neutron and gamma generator for nuclear well logging according to claim 1, characterized in that: The specific generation process of the neutron and gamma-ray mixed source is as follows: a control instruction is sent to the communication and control module by an external host computer; after the communication and control module parses the relevant instruction, the control driving component is controlled to lift the LiH moderator and the neutron absorber 1 from the storage position to the working position by driving the connecting rod; and then the controllable neutron generation module is controlled by the communication and control module to generate fast neutrons for logging, wherein part of the fast neutrons directly enter the formation after being generated, and the other part of the fast neutrons are slowed down by the LiH moderator to become thermal neutrons, and the thermal neutrons undergo neutron capture reaction with the neutron absorber 1 or the neutron absorber 2 to generate gamma rays of specific energy.

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