Elemental logging standard spectrum acquisition and spectrum unfolding method and related equipment

Abstract

The invention discloses an elemental logging standard spectrum acquisition and spectrum unfolding method and related equipment, and designs a mixed stratum-based standard spectrum acquisition method by considering the influence of stratum physical properties on a standard spectrum when the standard spectrum is acquired, thereby realizing the acquisition of the standard spectrum under different stratum conditions. The influence of the physical property change of the stratum on the interaction of rays and substances can be better simulated, so that a standard spectrum which can better reflect the physical property of the stratum can be obtained; in the spectrum unfolding process, the method for fitting or selecting the standard spectrum based on the stratum physical properties is designed, and compared with an existing spectrum unfolding method using a single standard spectrum, the method for fitting or selecting the standard spectrum based on the stratum physical properties has the advantages that the fitting formula is established; the standard spectrum is fitted or selected based on the stratum physical property obtained through actual detection, the influence of the stratum physical property on the standard spectrum is considered, the element content can be obtained through spectrum unfolding based on the physical property of the stratum to be detected, and the element spectrum unfolding precision is improved.

Description

Background Art

[0002] With the in-depth development of oil and gas resources, accurate understanding of the lithology and mineral composition of the formation has become an important issue that needs to be solved urgently. Element logging can obtain the elemental composition and porosity, formation density, oil saturation and other information of the formation, and can accurately identify the lithology of the formation. It is currently the only logging method that can identify the lithology by rock composition. Therefore, element logging has become a widely used nuclear logging method.

[0003] Due to the consumption of oil and gas resources, the exploration demand for conventional oil and gas reservoirs has decreased, and the formation environment that needs to be explored has become increasingly complex. The original logging method cannot meet the demand. Controlled source logging using pulsed neutron sources has many advantages over isotope logging. Unlike conventional isotope logging, the controlled source logging method uses 14MeV pulsed neutrons produced by deuterium-tritium nuclear fusion for logging. It has stronger penetration in the formation, higher efficiency in generating neutrons, and is safer and more controllable, and is not radioactive when the power is off.

[0004] The information carried by captured gamma, inelastic gamma, thermal neutrons and epithermal neutrons produced by the slowing down and absorption of pulsed neutrons in the formation can be analyzed to obtain the physical properties of the formation such as porosity, density, element content, etc. These advantages make it a new unconventional formation exploration method that has been valued and widely used.

[0005] Using standard spectrum for elemental analysis is a common method to obtain element content in elemental logging. In the process of controlled source logging, the 14MeV neutrons generated by the pulsed neutron source will undergo inelastic scattering, elastic scattering, neutron capture and other reactions in the formation. The inelastic scattering and neutron capture processes will emit a series of energy-separated gamma rays, which will interact with the atoms in the formation and the logging instrument. Some of the gamma rays will enter the detector to make the detector respond, and the energy spectrum finally obtained in the detector is a continuous curve. What needs to be done in elemental analysis is to use the existing standard spectrum from the obtained mixed energy spectrum, and use a certain mathematical method to solve the capture and inelastic yield of each element, and finally obtain the mass fraction of each element.

[0006] The existing method of obtaining a standard spectrum by building an experimental platform requires the use of extremely pure oxide or carbonate standard samples of formation elements. In actual operation, it is impossible to fully guarantee that the purity of the standard samples used meets the standards. Errors may occur due to impurities, and a complex correction process is required, which will affect the accuracy of the obtained standard spectrum. Therefore, Monte Carlo simulation is often used to obtain the standard spectrum. When using the simulation software, in order to make the formation density and the neutron slowing down length consistent, the standard spectrum can only be obtained by constructing a special single-layer formation. This is not enough to reflect the changes in the response coefficient under different formations, which is not conducive to improving the accuracy of the spectrum interpretation. Summary of the invention

[0007] The purpose of the present invention is to provide a method for acquiring and interpreting an element logging standard spectrum and related equipment to solve the technical problem that in the prior art, the influence of formation physical properties on the standard spectrum is not considered when acquiring the standard spectrum, which is not conducive to improving the accuracy of spectrum interpretation.

[0008] In order to achieve the above object, the present invention adopts the following technical scheme: A method for obtaining and interpreting an element logging standard spectrum comprises the following steps: Based on the standard spectrum acquisition method of mixed formations, standard spectra of different formation physical properties are obtained, and fitting formulas of standard spectra under different formation physical properties are obtained; Based on the formation physical property parameters obtained through measurement, the existing standard spectrum is fitted through a fitting formula to obtain the actual standard spectrum; Deconstruct the actual standard spectrum and the mixed spectrum by using a deconstruction analysis method; The steps of the standard spectrum acquisition method based on mixed formations are: By tracking the trajectory of particles, the source elements of the gamma rays entering the detector in the formation are obtained; The energy spectrum of gamma rays is classified and saved according to the source elements of the gamma rays, and the response energy spectrum of the detector to each element in the formation is obtained; According to the physical process of producing gamma rays in the formation, the captured standard spectrum and inelastic standard spectrum of each element in the mixed formation are finally obtained, and the standard spectrum is obtained by integration.

[0009] Furthermore, the detailed steps of the standard spectrum acquisition method based on mixed formations are: Obtain relevant information about particles in each interaction and mark them; Track the marked particles, assign the mixed energy spectrum data to each formation element, and obtain the capture and inelastic energy spectrum of each element; The obtained capture and inelastic energy spectra of each element are integrated to form a standard spectrum based on the mixed formation.

[0010] Furthermore, the obtaining of information about particles in each interaction and marking the particles includes: Obtain information about gamma rays produced in all interactions and mark them, and at the same time obtain information about the previous generation of particles that produced them to track particle trajectories; Relevant information about gamma rays generated by neutron capture and inelastic scattering in the formation is obtained respectively, and information about formation elements involved in the neutron capture reaction or inelastic scattering interaction is obtained respectively by analyzing the neutron capture reaction formula; Using a method for acquiring detector measurement data, information on gamma rays that ultimately arrive in a near gamma scintillation detector is obtained.

[0011] Furthermore, the tracking of the marked particles and the distribution of the mixed energy spectrum data to each formation element to obtain the capture and inelastic energy spectrum of each element include: Tracking the labeled particles, linking the primary gamma rays produced in the formation by the interaction of neutrons with atomic nuclei in the formation with the gamma rays that eventually reach the detector; Integrate the measurement information obtained in the detector into the corresponding primary generation of gamma rays; The relationship between the gamma rays produced by neutron capture and inelastic scattering in the formation and the formation elements involved in the reaction is used to relate the measurement information obtained from the gamma scintillation detector to different formation elements; The hybrid data are assigned to the trapped and inelastic energy spectra of each formation element.

[0012] Furthermore, the physical process of generating gamma rays in the formation includes radiation capture and inelastic scattering.

[0013] Furthermore, the physical properties of the formation include at least porosity, lithology and density of the formation.

[0014] Furthermore, the process of decomposing the actual standard spectrum and the mixed spectrum by using the decomposition spectrum analysis method is as follows: The mixed energy spectrum obtained by the detector and the actual standard spectrum are directly demodulated to obtain the capture yield and the non-elastic yield. The elemental spectrum analysis results were obtained by using the oxide closure model and multi-element bridging method; According to the element spectrum analysis results, the mass content of each element to be measured in the formation is obtained, and the element spectrum analysis process is completed.

[0015] In a second aspect, an element logging standard spectrum acquisition and spectrum interpretation system includes a fitting formula acquisition module, a standard spectrum acquisition module, and an element spectrum interpretation module, wherein: Fitting formula acquisition module: used to obtain standard spectra reflecting the physical properties of different formations based on the standard spectrum acquisition method of mixed formations, and to obtain fitting formulas of standard spectra under different physical properties of formations; Standard spectrum module: Based on the formation physical property parameters obtained through measurement, the existing standard spectrum is fitted through the fitting formula to obtain the actual standard spectrum; Element spectrum analysis module: used to analyze the actual standard spectrum and mixed spectrum through spectrum analysis method; The steps of the standard spectrum acquisition method based on mixed formations are: By tracking the trajectory of particles, the source elements of the gamma rays entering the detector in the formation are obtained; The energy spectrum of gamma rays is classified and saved according to the source elements of the gamma rays, and the response energy spectrum of the detector to each element in the formation is obtained; According to the physical process of producing gamma rays in the formation, the captured standard spectrum and inelastic standard spectrum of each element in the mixed formation are finally obtained, and the standard spectrum is obtained by integration.

[0016] In a third aspect, a terminal device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0017] In a fourth aspect, a computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a method for acquiring and interpreting a standard spectrum of element logging. When acquiring a standard spectrum, the influence of formation physical properties on the standard spectrum is taken into consideration, and a method for acquiring a standard spectrum based on a mixed formation is designed to achieve the acquisition of standard spectra under different formation conditions. Compared with the previously commonly used standard spectrum acquisition method based on a single formation, the method can better simulate the influence of changes in the physical properties of the formation on the interaction between rays and matter, thereby obtaining a standard spectrum that can better reflect the physical properties of the formation; when interpreting the spectrum, a method for fitting or selecting a standard spectrum based on the physical properties of the formation is designed. Compared with the existing interpreting method using a single standard spectrum, the method for fitting or selecting a standard spectrum based on the physical properties of the formation is designed by establishing a fitting formula, fitting or selecting a standard spectrum based on the physical properties of the formation obtained by actual detection, taking into consideration the influence of the physical properties of the formation on the standard spectrum, and can obtain a standard spectrum that reflects the physical properties of the formation, thereby improving the accuracy of element interpreting the spectrum.

[0019] The present invention provides a method for selecting and interpreting a standard spectrum based on the physical properties of a formation, designs a method for acquiring a standard spectrum based on a mixed formation and a method for fitting a standard spectrum based on the physical properties of a formation for fitting or selecting a standard spectrum. The establishment of these methods does not depend on specific logging instruments and detector types. Therefore, for different types of logging instruments and detectors, the method given in the present invention can be used to perform an elemental spectrum interpretation process based on the physical properties of the formation to obtain the mass content of each element to be measured, thereby improving the accuracy of the spectrum interpretation.

[0020] Furthermore, a method for obtaining standard spectra based on mixed formations designed based on the Monte Carlo simulation software Geant4 is presented to achieve the acquisition of captured standard spectra and non-elastic standard spectra in mixed formations. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of a method for obtaining and interpreting an element logging standard spectrum in an embodiment of the present invention; Figure 2 This is an overall flow chart of obtaining standard spectra based on formation physical properties in an element logging standard spectrum acquisition and spectrum interpretation method in an embodiment of the present invention; Figure 3 It is an overall flow chart of elemental spectrum analysis of formation physical properties using an elemental well logging standard spectrum acquisition and spectrum analysis method in an embodiment of the present invention; Figure 4 This is a schematic diagram of the step hierarchy of the standard spectrum acquisition procedure based on mixed formations of the present invention; Figure 5 It is a schematic diagram of the event level of the standard spectrum acquisition program based on mixed formations of the present invention; Figure 6 It is a schematic diagram of the run level of the standard spectrum acquisition program based on mixed formations of the present invention; Figure 7 This is a process flow chart of fitting or selecting a standard spectrum for spectrum interpretation based on formation physical properties in the present invention; Figure 8 A visualization model diagram and a 3D modeling schematic diagram of a controlled neutron source logging tool selected for an embodiment of the present invention in a Monte Carlo simulation program Geant4; Fig. 9 The capture standard spectrum at the standard porosity of 5 pu; Fig.10 Inelastic standard spectrum at standard porosity of 5 pu; Fig.11 The capture standard spectrum at the standard porosity of 13.2 pu; Fig.12 Inelastic standard spectrum at standard porosity of 13.2 pu; Fig.13 The capture standard spectrum at the standard porosity of 20.2 pu; Fig.14 Inelastic standard spectrum at standard porosity of 20.2 pu; Fig.15 The capture standard spectrum at the standard porosity of 30 pu; Fig.16 Inelastic standard spectrum at standard porosity of 30 pu; Fig.17 The capture standard spectrum at the standard porosity of 37.2 pu; Fig.18 Inelastic standard spectrum at standard porosity of 37.2 pu; Fig.19The capture standard spectrum at the standard porosity of 52.9 pu; Fig. 20 Inelastic standard spectrum at standard porosity of 52.9 pu; DETAILED DESCRIPTION The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0023] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0024] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0025] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings: like Figure 1 As shown, a method for obtaining and interpreting an element logging standard spectrum comprises the following steps: Step 1: Based on the standard spectrum acquisition method of mixed formations, standard spectra of different formation physical properties are obtained, and fitting formulas of standard spectra under different formation physical properties are obtained: Specifically, a standard spectrum acquisition method based on mixed formations is designed to obtain standard spectra corresponding to different elements in mixed formations. According to the designed standard spectrum acquisition method, a set of standard spectra under different formation conditions are obtained through computer numerical simulation. Based on the obtained set of standard spectra under different formation physical properties, fitting is performed to obtain the fitting formula of standard spectra under different physical properties.

[0027] Step 2: Based on the formation physical property parameters obtained through measurement, the existing standard spectrum is fitted through a fitting formula to obtain the actual standard spectrum.

[0028] Step 3, deconstructing the actual standard spectrum and the mixed spectrum by using a deconstruction analysis method; Specifically, a capture-inelastic joint decomposition method is designed based on fitting or selecting standard spectra based on formation physical properties; according to known formation conditions, a set of standard spectra under different formation conditions obtained through computer numerical simulation are fitted or selected, and a decomposition program is used to perform decomposition based on the standard spectra adapted to the formation conditions obtained by fitting or selecting; based on the decomposition results of the decomposition program, the mass fraction of each element to be measured in the formation is analyzed to complete the element decomposition.

[0029] The steps of the standard spectrum acquisition method based on mixed formations are as follows: By tracking the trajectory of particles, the source elements of the gamma rays entering the detector in the formation are obtained; The energy spectrum of gamma rays is classified and saved according to the source elements of the gamma rays, and the response energy spectrum of the detector to each element in the formation is obtained; According to the physical process of gamma ray generation in the formation, the captured standard spectrum and the inelastic standard spectrum of each element in the mixed formation are finally obtained, and the standard spectrum is obtained by integration; Specifically, the standard spectrum to be obtained is divided into a capture standard spectrum and an inelastic standard spectrum, that is, the corresponding standard spectrum can be obtained by integrating the two. The physical process mentioned in the above steps is radiation capture and inelastic scattering.

[0030] In one embodiment of the present invention, a method for obtaining and interpreting an element logging standard spectrum is provided. The detailed process is as follows: Figure 7 As shown, it includes the standard spectrum acquisition and spectrum interpretation process. The standard spectrum acquisition is as follows Figure 2 As shown in Figure 3 The specific steps shown are as follows: Step 1: Design a method for obtaining standard spectra in mixed formations. By identifying the initial formation source elements of the gamma rays reaching the gamma detector, it is possible to obtain the energy spectrum data of the inelastic standard spectrum and the capture standard spectrum of all the formation elements to be measured by performing a single simulation in mixed formations. According to this method, a standard spectrum acquisition program is established using a computer program. The program flow chart is shown in Figure 4-Figure 6 As shown; Step 2: According to the designed standard spectrum acquisition method based on mixed formations, the Monte Carlo simulation program is used to model the well logging tool and formation, and the standard spectrum acquisition program is completed; Step 3: According to the completed standard spectrum acquisition procedure, by changing the physical properties of the formation, a set of standard spectra that can reflect the physical properties of different formations are obtained through Monte Carlo simulation; Step 4: According to a set of standard spectra under different formation physical properties, fitting is performed to obtain fitting formulas of standard spectra under different physical properties; Step 5: Based on the fitting formula, a standard spectrum fitting and selection program is established. The program can fit or select the standard spectrum according to the input measured formation physical properties, so as to carry out the subsequent spectrum interpretation work. The process of fitting or selecting the standard spectrum is shown in Figure 6.

[0031] Step 6: According to the established standard spectrum fitting selection program, a standard spectrum that meets the physical properties of the formation to be measured is obtained, and the standard spectrum is imported into the spectrum analysis program for element spectrum analysis. The relative content of each element is obtained according to the spectrum analysis results. The element spectrum analysis process is as follows: First, the mixed energy spectrum obtained by the detector and the selected standard spectrum are imported into the program; then the capture yield and inelastic yield are calculated by direct demodulation method; then the elemental spectrum results are obtained by oxide closure model and multi-element bridging method; Finally, the mass content of each element to be measured in the formation can be obtained by analyzing the element spectrum analysis results, completing the element spectrum analysis process.

[0032] In another embodiment provided by the present invention, a standard spectrum acquisition method based on a mixed formation is used to establish a standard spectrum acquisition program using a computer program, and a standard spectrum acquisition method based on a mixed formation is designed based on the Monte Carlo simulation software Geant4 to achieve acquisition of captured standard spectrum and non-elastic standard spectrum in a mixed formation. The program flow chart is shown in FIG. Figure 4-Figure 6 As shown; The program contains three levels: step, event, and run: At the step level, Figure 4As shown, the main content is to obtain relevant information of particles in each interaction in order to carry out further work in the event level. First, the information of gamma rays generated in all interactions occurring in the simulation is obtained and marked, and the information of the previous generation particles that generated it is obtained at the same time, so as to track the particle trajectory. Then, the relevant information of gamma rays generated by neutron capture and inelastic scattering in the formation is obtained respectively. By analyzing the neutron capture reaction formula, the information of the formation elements participating in the neutron capture reaction or inelastic scattering interaction is obtained respectively. Finally, the conventional method of obtaining detector measurement data is used to obtain the information of gamma rays that finally reach the near gamma scintillation detector. In the event level, such as Figure 5 As shown in the figure, the main content is to distribute the energy spectrum raw data obtained by the detector to the formation elements that have different interactions with gamma rays (neutron capture and inelastic scattering) through the information obtained in the step level, which includes three steps: first, particle tracking is performed by the labeling method to link the primary gamma rays generated by the interaction between neutrons and atomic nuclei in the formation with the gamma rays that finally reach the detector, and then the measurement information obtained in the detector is integrated into the corresponding primary gamma rays (one primary gamma ray may correspond to multiple gamma rays that reach the detector), and finally, the measurement information obtained in the gamma scintillation detector is linked to different formation elements by the relationship between the gamma rays generated by neutron capture and inelastic scattering in the formation and the formation elements (atomic nuclei) involved in the reaction (distinguishing neutron capture and inelastic scattering); In the run level, such as Figure 6 As shown in the figure, the main content is to integrate the information obtained from each event and make it into an energy spectrum, and finally form a capture standard spectrum and a non-elastic standard spectrum based on the mixed formation.

[0033] The logging tool and formation model were established in Geant4. The controlled neutron source logging tool model was selected as follows: Figure 8 As shown in the figure, the main components of the controlled neutron source logging instrument include LaBr scintillator detector, He-3 gas detector, pulsed neutron source, shield and boron sleeve, etc. The total length of the instrument is 2.6 meters, including pulsed neutron source, tungsten nickel iron shield, 4 far thermal neutron detectors, 1 near thermal neutron detector, 1 epithermal neutron detector, 1 near LaBr scintillator detector, 1 far LaBr scintillator detector and other supporting parts; the specific parameter settings of the simulation model are as follows: (1) Strata: The height of the stratum is set to 3m and the radius is 100cm. A multi-element mixed stratum is used, and the stratum constituent elements and density are replaced according to actual conditions.

[0034] (2) Wellbore: The radius is set to 10.15cm and the height is the same as the formation. The interior is filled with pure water.

[0035] (3) Overall instrument: The total height of the instrument is 2.01m, and the maximum radius is 6.05cm. The instrument is placed close to the well wall and is surrounded by air. The shell material is set to titanium steel TC11 and TC18.

[0036] (4) The neutron source is set to a radius of 0.575 cm, an isotropic surface source, and the energy is set to 14 MeV.

[0037] (5) The shield is made of tungsten-nickel-iron alloy with a density of 18 g / cm 3 . The thickness is 12.5cm.

[0038] (6) Near-gamma scintillator detector: The source distance is 44.3 cm, and the scintillator crystal uses lanthanum bromide (LaBr 3 ), density is 5.3g / cm 3 .

[0039] (7) Other detectors: The neutron detector is filled with He-3; the material and size of the far-source gamma detector are the same as those of the near-source gamma detector.

[0040] According to the above modeling parameters and the designed standard spectrum acquisition method, a standard spectrum acquisition program based on mixed formations is established.

[0041] Taking formation porosity in formation physical properties as an example, a set of captured standard spectra and non-elastic standard spectra were obtained by simulating mixed formations with different porosities through the designed Geant4-based standard spectrum acquisition program; the porosities were selected as 5 pu, 13.2 pu, 20.2 pu, 30 pu, 37.2 pu, and 52.9 pu. The obtained set of standard spectra is as follows Figures 9 to 20 shown.

[0042] By fitting a set of captured standard spectra and inelastic standard spectra at different porosities, the fitting formulas of standard spectra at different porosities are obtained, as shown in formulas (1) to (5): (1) (2) (3) (4) (5) In the formula, is the standard spectrum when the porosity is x pu; formula (1) is applicable to the case where the porosity of the formation to be measured is 0 p.u.-13 p.u., formula (2) is applicable to the case where the porosity of the formation to be measured is 13 p.u.-20 p.u., formula (3) is applicable to the case where the porosity of the formation to be measured is 20 p.u.-30 p.u., formula (4) is applicable to the case where the porosity of the formation to be measured is 30 pu-37 p.u., and formula (5) is applicable to the case where the porosity of the formation to be measured is 37 p.u.-52 p.u.

[0043] Assuming that in actual well logging, the porosity of the formation is 7 p.u. obtained by the near-far neutron ratio obtained by the neutron detector, the new standard spectrum obtained by the standard spectrum fitting procedure can be expressed by formula (6): (6) The standard spectra of 5 p.u. and 13 p.u. are fitted using formula (6) to obtain the standard spectrum at 7 pu. The substituted standard spectrum is imported into the spectrum analysis program, and the mixed spectrum data is obtained by simulating the formation under this porosity.

[0044] The mixed spectrum and standard spectrum were imported into the spectrum analysis program to obtain the captured yield and inelastic yield of each element, and the mass fraction of each element was obtained through the oxide closure model and multi-element bridging method.

[0045] Table 1 Spectral analysis results of the fitting method used in the present invention

[0046] Table 2 Spectral analysis results of standard spectra under similar standard porosity

[0047] The mass fractions of elements in the formation simulated by different methods are compared with the mass fractions actually set, as shown in Tables 1, 2 and 3. The analysis results show that the average relative error between the simulated value and the actual set value of the mass fraction of each element in the spectrum interpretation result (Table 1) of the fitting method used in the present invention is 5.243%, the average relative error of the spectrum interpretation result (Table 2) using the standard spectrum under the standard porosity obtained by the present invention for spectrum interpretation is 14.401%, and the average relative error of the spectrum interpretation result (Table 3) using a single standard spectrum is 28.173%, indicating that the standard spectrum acquisition and spectrum interpretation method based on the physical properties of the formation provided by the present invention greatly improves the accuracy of element spectrum interpretation.

[0048] Table 3 Spectral analysis results using a single standard spectrum

[0049] It will be appreciated by those skilled in the art that various aspects of the present invention may be implemented as systems, methods or program products. Therefore, various aspects of the present invention may be specifically implemented in the following forms, namely: complete hardware implementation, complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software implementations, which may be collectively referred to herein as "circuits", "modules" or "platforms".

[0050] In yet another embodiment of the present invention, there is also provided an element logging standard spectrum acquisition and spectrum interpretation system, comprising a fitting formula acquisition module, a standard spectrum acquisition module, and an element spectrum interpretation module, wherein: Fitting formula acquisition module: used to obtain standard spectra reflecting the physical properties of different formations based on the standard spectrum acquisition method of mixed formations, and to obtain fitting formulas of standard spectra under different physical properties of formations; Standard spectrum module: Based on the formation physical property parameters obtained through measurement, the existing standard spectrum is fitted through the fitting formula to obtain the actual standard spectrum; Element spectrum analysis module: used to analyze the actual standard spectrum and mixed spectrum through spectrum analysis method; The steps of the standard spectrum acquisition method based on mixed formations are: By tracking the trajectory of particles, the source elements of the gamma rays entering the detector in the formation are obtained; The energy spectrum of gamma rays is classified and saved according to the source elements of the gamma rays, and the response energy spectrum of the detector to each element in the formation is obtained; According to the physical process of producing gamma rays in the formation, the captured standard spectrum and inelastic standard spectrum of each element in the mixed formation are finally obtained, and the standard spectrum is obtained by integration.

[0051] A terminal device provided in one embodiment of the present invention comprises: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned method embodiments are implemented. Alternatively, when the processor executes the computer program, the functions of the modules / units in the above-mentioned device embodiments are implemented.

[0052] The computer program may be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to accomplish the present invention.

[0053] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0054] The processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0055] The memory may be used to store the computer programs and / or modules, and the processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory and calling the data stored in the memory.

[0056] If the module / unit integrated in the terminal device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0057] The present invention provides a method for selecting and interpreting a standard spectrum based on the physical properties of the formation, designs a method for obtaining a standard spectrum based on a mixed formation and a method for fitting or selecting a standard spectrum based on the physical properties of the formation. The establishment of these methods does not depend on the specific logging instrument and detector type. Therefore, for different types of logging instruments and detectors, the elemental spectrum interpretation process can be performed based on the physical properties of the formation according to the method given in this patent to obtain the mass content of each element to be measured, thereby improving the accuracy of the spectrum interpretation, which is very convenient in practical applications. The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for obtaining and interpreting standard element logging spectra, characterized in that: The following steps are involved: Based on the standard spectrum acquisition method of mixed formations, standard spectra of different formation physical properties are obtained, and fitting formulas of standard spectra under different formation physical properties are obtained; Based on the formation physical property parameters obtained through measurement, the existing standard spectrum is fitted through a fitting formula to obtain the actual standard spectrum; Deconstruct the actual standard spectrum and the mixed spectrum by using a deconstruction analysis method; The steps of the standard spectrum acquisition method based on mixed formations are: By tracking the trajectory of particles, the source elements of the gamma rays entering the detector in the formation are obtained; The energy spectrum of gamma rays is classified and saved according to the source elements of the gamma rays, and the response energy spectrum of the detector to each element in the formation is obtained; According to the physical process of gamma ray generation in the formation, the capture energy spectrum and inelastic energy spectrum of each element in the mixed formation are obtained, and finally the standard spectrum is integrated.

2. The method for obtaining and interpreting an element logging standard spectrum according to claim 1, characterized in that: The detailed steps of the standard spectrum acquisition method based on mixed formations are: Obtain relevant information about particles in each interaction and mark them; Track the marked particles, assign the mixed energy spectrum data to each formation element, and obtain the capture and inelastic energy spectrum of each element; The obtained capture and inelastic energy spectra of each element are integrated to form a standard spectrum based on the mixed formation.

3. The method for obtaining and interpreting an element logging standard spectrum according to claim 2, characterized in that: The obtaining and marking of information about particles in each interaction includes: Obtain information about gamma rays produced in all interactions and mark them, and at the same time obtain information about the previous generation of particles that produced them to track particle trajectories; Relevant information about gamma rays generated by neutron capture and inelastic scattering in the formation is obtained respectively, and information about formation elements involved in the neutron capture reaction or inelastic scattering interaction is obtained respectively by analyzing the neutron capture reaction formula; Using a method for acquiring detector measurement data, information on gamma rays that ultimately arrive in a near gamma scintillation detector is obtained.

4. The method for obtaining and interpreting an element logging standard spectrum according to claim 2, characterized in that: The method of tracking the marked particles and assigning the mixed energy spectrum data to each formation element to obtain the capture and inelastic energy spectrum of each element includes: Tracking the labeled particles, linking the primary gamma rays produced in the formation by the interaction of neutrons with atomic nuclei in the formation with the gamma rays that eventually reach the detector; Integrate the measurement information obtained in the detector into the corresponding primary generation of gamma rays; The relationship between the gamma rays produced by neutron capture and inelastic scattering in the formation and the formation elements involved in the reaction is used to relate the measurement information obtained from the gamma scintillation detector to different formation elements; The hybrid data are assigned to the trapped and inelastic energy spectra of each formation element.

5. The method for obtaining and interpreting an element logging standard spectrum according to claim 1, characterized in that: The physical processes that generate gamma rays in the formation include radiation capture and inelastic scattering.

6. The method for obtaining and interpreting element logging standard spectrum according to claim 1, characterized in that: The physical properties of the formation include at least the porosity, lithology and density of the formation.

7. A method for obtaining and interpreting element logging standard spectra according to claim 1 or 5, characterized in that: The process of decomposing the actual standard spectrum and the mixed spectrum by using the decomposition spectrum analysis method is as follows: The mixed energy spectrum obtained by the detector and the actual standard spectrum obtained by fitting are used to calculate the capture yield and the inelastic yield through direct demodulation method. The elemental spectrum analysis results were obtained by using the oxide closure model and multi-element bridging method; According to the element spectrum analysis results, the mass content of each element to be measured in the formation is obtained, and the element spectrum analysis process is completed.

8. An element logging standard spectrum acquisition and spectrum interpretation system, characterized in that: It includes fitting formula acquisition module, standard spectrum acquisition module and element spectrum analysis module, among which: Fitting formula acquisition module: used to obtain standard spectra reflecting the physical properties of different formations based on the standard spectrum acquisition method of mixed formations, and to obtain fitting formulas of standard spectra under different physical properties of formations; Standard spectrum module: Based on the formation physical property parameters obtained through measurement, the existing standard spectrum is fitted through the fitting formula to obtain the actual standard spectrum; Element spectrum analysis module: used to analyze the actual standard spectrum and mixed spectrum through spectrum analysis method; The steps of the standard spectrum acquisition method based on mixed formations are: By tracking the trajectory of particles, the source elements of the gamma rays entering the detector in the formation are obtained; The energy spectrum of gamma rays is classified and saved according to the source elements of the gamma rays, and the response energy spectrum of the detector to each element in the formation is obtained; According to the physical process of producing gamma rays in the formation, the captured standard spectrum and inelastic standard spectrum of each element in the mixed formation are finally obtained, and the standard spectrum is obtained by integration.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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