Shale vitrinite reflectivity determination method and device based on neutron-density envelope area, computer equipment and storage medium

Abstract

The invention discloses a shale vitrinite reflectivity determination method and device based on a neutron-density envelope area, computer equipment and a storage medium, and relates to the technical field of oil and gas exploration and development. According to the method, address characteristics of a research area and a logging response rule are combined, left and right scales of a compensated neutron and lithologic density logging curve of the research area are fixed, unit areas of the compensated neutron and the lithologic density logging curve are calculated firstly, and then envelope areas of the compensated neutron and the lithologic density logging curve are determined; and establishing a relationship between the enveloping area and the vitrinite reflectance of core analysis by adopting a mathematical fitting model, so as to quickly and quantitatively calculate and predict the shale vitrinite reflectance of the well. The operation method is simple, the replicability is high, the calculation progress is high, the calculation result meets the field requirement of an oil field, and the method has good universality and popularization value especially in old well review with deficient data.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploration and development, and more specifically to a method, device, computer equipment and storage medium for determining shale vitrinite reflectivity based on neutron-density envelope area. Background Art

[0002] In recent years, with the increasing demand for oil and gas resources in the world and the growing awareness and demand for clean energy, conventional oil and gas resources can no longer meet the needs of the country, society and individuals. With the continuous development of resource exploration and development, my country has gradually shifted the focus of exploration and development to unconventional oil and gas resources. Shale oil was first discovered and recognized in the 1720s.

[0003] The exploration, development and use of shale oil meet the needs of green development in the world and my country. Global shale oil resources are very abundant.

[0004] The research on shale reservoirs mainly focuses on the mineral composition, physical properties, oil content, geochemistry and rock mechanics parameters of the reservoirs, among which the research on geochemical parameters mainly focuses on the organic matter in the formations. However, due to the large differences in geological characteristics such as sedimentary environment, lithology, lithofacies, mineral composition and evolution stage in various regions, the use of traditional shale evaluation methods to evaluate reservoir geochemical parameters will result in low evaluation accuracy and even failure of the evaluation method.

[0005] Organic matter is not only the material basis for the formation of hydrocarbons, but also provides an important carrier for the adsorption of shale oil. In addition, in the process of converting organic matter into hydrocarbons, the organic pores and microcracks formed are also important places for the occurrence of shale oil. The abundance and maturity of organic matter are important indicators of the development degree of shale oil.

[0006] Organic matter maturity is a parameter that characterizes the degree of organic matter evolution, and can determine the effectiveness of rock hydrocarbon generation and the properties of the products. Vitrinite reflectance is an optical indicator that characterizes the maturity of organic matter and is an important parameter for evaluating the hydrocarbon generation of organic matter. Vitrinite reflectance has the characteristics of simple operation, short cycle and low cost. At the same time, it reacts in organic diagenesis, deep diagenesis and metamorphism, and has a positive correlation and irreversibility with organic matter maturity. Therefore, domestic and foreign scholars regard it as an important parameter for evaluating organic matter maturity. Although domestic and foreign scholars have conducted in-depth research on shale reservoir evaluation this year, the quantitative evaluation of vitrinite reflectance using logging data has received less attention, especially the lack of data from old wells in oil fields, and the difficulty in evaluating shale vitrinite reflectance. Summary of the invention

[0007] In order to overcome the defects and deficiencies in the above-mentioned prior art, the present invention provides a method, device, computer equipment and storage medium for determining the shale vitrinite reflectance based on the neutron-density envelope area. The purpose of the present invention is to solve the problem of lack of data on old wells in oil fields and difficulty in evaluating the shale vitrinite reflectance. The present invention combines the address characteristics of the study area with the logging response law, fixes the left and right scales of the compensated neutron and lithology density logging curves in the study area, first calculates the unit area of ​​the compensated neutron and lithology density logging curves, and then determines the envelope area of ​​the two, and then uses a mathematical fitting model to establish the relationship between the envelope area and the core analysis vitrinite reflectance, so as to achieve rapid quantitative calculation of the shale vitrinite reflectance of the predicted well. The present invention has a simple operation method, strong reproducibility, high calculation progress, and the calculation results meet the needs of the oil field site. Especially in the review of old wells with scarce data, it has good universality and promotion value.

[0008] In order to solve the above problems existing in the prior art, the present invention is implemented through the following technical solutions.

[0009] The first aspect of the present invention provides a method for determining the shale vitrinite reflectance based on the neutron-density envelope area, the determination method comprising the following steps: S1. Take shale cores from multiple wells in the study area, conduct vitrinite reflectance experimental measurements on the shale cores of each well, and obtain vitrinite reflectance experimental data for core analysis of each well; S2, obtaining the well logging curve data of the well corresponding to the core of each well in step S1; S3, plotting the vitrinite reflectance of the core analysis obtained in step S1 and the well logging curve of the corresponding well obtained in step S2 on the same graph; S4. In the graph drawn in step S3, the left and right scales of the compensated neutron and lithology density logging curves are adjusted so that the compensated neutron and lithology density logging curves overlap in the sandstone reservoir section; S5, calculating the envelope area of ​​the compensated neutron and lithology density logging curves of the wells corresponding to each core; S6. Analyze the relationship between the vitrinite reflectance at the depth point of the shale core measurement of each well and the corresponding envelope area, and establish a vitrinite reflectance logging interpretation model for shale in the study area; S7. Based on the shale vitrinite reflectance logging interpretation model established in step S6, combined with the compensated neutron and lithology density logging curves in the prediction well, quantitatively calculate the shale vitrinite reflectance in the prediction well.

[0010] Further preferably, in step S1, the experimental data of vitrinite reflectance of core analysis is obtained according to the process specified in the standard "SY / T5124-2012 Method for Determination of Vitrinite Reflectance in Sedimentary Rocks".

[0011] Further preferably, in step S3, the vitrinite reflectance of the core analysis and the natural gamma (GR), compensated neutron (CNL) and core density (DEN) logging curves of the well corresponding to the core are plotted on the same graph.

[0012] More preferably, the vitrinite reflectance of the core analysis is displayed using a bar graph.

[0013] Further preferably, in step S4, the left and right scales of the compensated neutron and core density logging curves are adjusted, specifically, the compensated neutron and core density logging curves are both linearly scaled, and the scale range is [CNL L ,CNL R ] and [DEN L ,DEN R ] so that the compensated neutron and core density logging curves overlap in the sandstone reservoir section.

[0014] Further preferably, in step S5, a one-to-one mapping method is used to eliminate the difference in physical dimension level between the compensated neutron and core density logging curves, calculate the unit area of ​​the compensated neutron and core density logging curves, and determine the envelope area of ​​the compensated neutron and lithology density logging curves.

[0015] More preferably, the unit area of ​​the compensated neutron logging curve is: ; In the formula, CNL is the compensated neutron value, %; and compensated neutron unit area, dimensionless.

[0016] More preferably, the unit area of ​​the lithology density logging curve is: , where DEN is the lithology density, g / cm 3 ; Lithology density per unit area, dimensionless.

[0017] More preferably, the envelope area of ​​the compensated neutron and lithology density logging curve is: , where mjc is the envelope area of ​​the compensated neutron and lithology density logging curves, dimensionless.

[0018] Further preferably, in step S6, a shale vitrinite reflectance logging interpretation model for the study area is established by statistically analyzing the shale vitrinite reflectance at the core measurement depth points of multiple wells and the corresponding envelope areas. The model expression is: , where Ro is the vitrinite reflectance of core analysis; and a and b are model parameters.

[0019] Further preferably, in step S7, the compensated neutron and lithology density logging curves in the prediction well are combined, specifically, the envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well is calculated based on the compensated neutron and lithology density logging curves of the prediction well, and the calculated envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well is substituted into the shale vitrinite reflectance logging interpretation model established in step S6 to calculate the shale vitrinite reflectance of the prediction well.

[0020] A second aspect of the present invention provides a device for determining shale vitrinite reflectance based on neutron-density envelope area, the device comprising: The data acquisition module is used to obtain the experimental data of vitrinite reflectance of the core analysis of each well in the study area and the logging curves of the wells corresponding to the core; The logging curve drawing module is used to draw the vitrinite reflectance of the core analysis and the logging curve of the well corresponding to the core on the same graph; The logging curve adjustment module is used to adjust the left and right scales of the compensation neutron and lithology density logging defects so that the compensation neutron and lithology density logging defects overlap in the sandstone reservoir section; An envelope area calculation module is used to calculate the envelope area of ​​the compensated neutron and lithology density measurement curves of the wells corresponding to each core; The statistical modeling module conducts statistical analysis on the vitrinite reflectance and corresponding envelope area of ​​core measurement depth points of multiple wells, and establishes a shale vitrinite reflectance logging interpretation model in the study area; The module for calculating the shale vitrinite reflectance in the prediction well obtains the compensated neutron and lithology density logging curves in the prediction well, substitutes them into the shale vitrinite reflectance logging interpretation model established by the statistical modeling module, and calculates the shale vitrinite reflectance in the prediction well.

[0021] Further preferably, in the logging curve drawing module, the vitrinite reflectance of the core analysis and the natural gamma (GR), compensated neutron (CNL) and core density (DEN) logging curves of the well corresponding to the core are drawn on the same graph.

[0022] More preferably, in the logging curve drawing module, the vitrinite reflectance of the core analysis is displayed in a rod graph.

[0023] Further preferably, in the logging curve adjustment module, the left and right scales of the compensated neutron and core density logging curves are adjusted, specifically, the compensated neutron and core density logging curves are both linearly scaled, and the scale range is [CNL L ,CNL R ] and [DEN L ,DEN R ] so that the compensated neutron and core density logging curves overlap in the sandstone reservoir section.

[0024] Further preferably, in the envelope area calculation module, a one-to-one mapping method is used to eliminate the difference in physical dimension level between the compensated neutron and core density logging curves, calculate the unit area of ​​the compensated neutron and core density logging curves, and determine the envelope area of ​​the compensated neutron and lithology density logging curves.

[0025] More preferably, the unit area of ​​the compensated neutron logging curve is: ; In the formula, CNL is the compensated neutron value, %; CNL L To compensate for the neutron left scale end value, CNL R To compensate for the right end of the neutron scale, to compensate for the neutron unit area, dimensionless.

[0026] More preferably, the unit area of ​​the lithology density logging curve is: , where DEN is the lithology density, g / cm 3 ;DEN L DWN is the left end value of the lithology density. R It is the right end value of the lithology density, lithology density per unit area, dimensionless.

[0027] More preferably, the envelope area of ​​the compensated neutron and lithology density logging curve is: , where mjc is the envelope area of ​​the compensated neutron and lithology density logging curves, dimensionless.

[0028] Further preferably, in the statistical modeling module, the shale vitrinite reflectance and the corresponding envelope area at the core measurement depth points of multiple wells are statistically analyzed to establish a shale vitrinite reflectance logging interpretation model in the study area. The model expression is: , where Ro is the vitrinite reflectance of core analysis; and a and b are model parameters.

[0029] Further preferably, in the prediction well shale vitrinite reflectance calculation module, the envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well is calculated based on the compensated neutron and lithology density logging curves of the prediction well, and the calculated envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well is substituted into the shale vitrinite reflectance logging interpretation model established by the statistical modeling module to calculate the shale vitrinite reflectance of the prediction well.

[0030] The third aspect of the present invention provides a computer device, comprising a processor, an input device, an output device and a memory, wherein the processor, the input device, the output device and the memory are interconnected, wherein the memory is used to store a computer program, the computer program comprises program instructions, and the processor is configured to call the program instructions to execute some or all of the steps described in the first aspect of the present invention.

[0031] The fourth aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute some or all of the steps described in the first aspect of the present invention.

[0032] Compared with the prior art, the beneficial technical effects brought by the present invention are as follows: The present invention provides a method for determining the shale vitrinite reflectance based on the neutron-density envelope area. Combining the geological characteristics of the study area with the logging response law, by fixing the left and right scales of the compensated neutron and lithology density logging curves in the study area, the unit area of ​​the compensated neutron and lithology density logging curves is first calculated, and then the envelope area of ​​the two is determined, and then a mathematical fitting model is used to establish the relationship between the envelope area and the vitrinite reflectance of the core analysis, so as to achieve rapid quantitative calculation of the shale vitrinite reflectance of the predicted well. The method of the present invention is simple, easy to operate, highly reproducible, and has a high calculation progress. The calculation results meet the needs of the oil field site, especially in the review of old wells with scarce data, and have good universality and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a flow chart of a method for determining shale vitrinite reflectance based on neutron-density envelope area of ​​the present invention; Figure 2 It is a comparison diagram of the calculation results of the vitrinite reflectance of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings of the present invention specification to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0035] Example 1 As a preferred embodiment of the present invention, refer to the attached specification Figure 1 As shown, this embodiment discloses a method for determining the shale vitrinite reflectance based on the neutron-density envelope area, and the determination method comprises the following steps: S1. Take shale cores from multiple wells in the study area, conduct vitrinite reflectance experimental measurements on the shale cores of each well, and obtain vitrinite reflectance experimental data for core analysis of each well; S2, obtaining the well logging curve data of the well corresponding to the core of each well in step S1; S3, plotting the vitrinite reflectance of the core analysis obtained in step S1 and the well logging curve of the corresponding well obtained in step S2 on the same graph; S4. In the graph drawn in step S3, the left and right scales of the compensated neutron and lithology density logging curves are adjusted so that the compensated neutron and lithology density logging curves overlap in the sandstone reservoir section; S5, calculating the envelope area of ​​the compensated neutron and lithology density logging curves of the wells corresponding to each core; S6. Analyze the relationship between the vitrinite reflectance at the depth point of the shale core measurement of each well and the corresponding envelope area, and establish a vitrinite reflectance logging interpretation model for shale in the study area; S7. Based on the shale vitrinite reflectance logging interpretation model established in step S6, combined with the compensated neutron and lithology density logging curves in the prediction well, quantitatively calculate the shale vitrinite reflectance in the prediction well.

[0036] Example 2 As another preferred embodiment of the present invention, this embodiment discloses a method for determining the shale vitrinite reflectance based on the neutron-density envelope area, and the determination method comprises the following steps: S1. Take shale cores from multiple wells in the study area, conduct vitrinite reflectance experimental measurements on the shale cores of each well, and obtain the vitrinite reflectance (Ro) experimental data of the core analysis of each well. The vitrinite reflectance (Ro) experimental data of the core analysis is obtained according to the process specified in the standard "SY / T5124-2012 Method for Determination of Vitrinite Reflectance in Sedimentary Rocks".

[0037] S2, obtaining the well logging curve data of the well corresponding to the core of each well in step S1; S3. Plot the vitrinite reflectance of the core analysis obtained in step S1 and the well logging curve of the well corresponding to the core on the same graph, wherein the well logging curve includes a natural gamma (GR) logging curve, a compensated neutron (CNL) logging curve and a lithology density (DEN) logging curve, that is, plot the vitrinite reflectance of the core analysis and the natural gamma (GR), compensated neutron (CNL) and lithology density (DEN) logging curves of the well corresponding to the core on the same graph.

[0038] The most preferred solution is to display the vitrinite reflectance of the core analysis in a bar graph (see Appendix Figure 2According to the actual working conditions, the vitrinite reflectance of the core analysis can be displayed in other shapes, such as bar graphs, dot graphs, etc.

[0039] S4. In the graph drawn in step S3, adjust the left and right scales of the compensated neutron and lithology density logging curves in combination with the geological characteristics of the study area and the corresponding logging law. Since the geological characteristics and logging response laws of different regions are different, according to the actual situation of the study area, adjust the left and right scales of the compensated neutron and lithology density logging curves so that the compensated neutron and lithology density logging curves overlap in the sandstone reservoir section (as shown in the attached manual). Figure 2 The second track (2985-2992m) uses a linear scale for compensated neutrons, with a scale range of [45, -15]; the lithology density uses a linear scale, with a scale range of [1.95, 2.95].

[0040] S5. Use a one-to-one mapping method to eliminate the difference in physical dimension level between the compensated neutron and lithology density logging curves, calculate the unit area of ​​the compensated neutron and lithology density logging curves, and determine the envelope area of ​​the compensated neutron and lithology density logging curves.

[0041] Calculate the unit area of ​​the compensated neutron curve, as shown in the attached manual. Figure 2 The 4th CNL_mj curve: , where CNL is the compensated neutron value, %; and compensated neutron unit area, dimensionless.

[0042] Calculate the unit area of ​​the lithology density logging curve, as shown in the attached manual. Figure 2 The fourth DEN_mj curve: , where DEN is the lithology density, g / cm 3 ; Lithology density per unit area, dimensionless.

[0043] Calculate the envelope area of ​​compensated neutron and lithology density logging curves, as shown in the attached manual. Figure 2 The 4th gray filled part, the 5th to the mjc curve: , where mjc is the envelope area of ​​compensated neutron and lithology density logging curves, dimensionless.

[0044] S6. Analyze the relationship between the vitrinite reflectance at the core measurement depth point of each well and the corresponding envelope area, and establish a logging interpretation model for the vitrinite reflectance of shale in the study area. Specifically, statistically analyze the vitrinite reflectance at the core measurement depth point of multiple wells and the corresponding envelope area, and establish a logging interpretation model for the vitrinite reflectance of shale in the study area. The model expression is: , where Ro is the vitrinite reflectance of core analysis; and a and b are model parameters.

[0045] By statistically analyzing the relationship between the vitrinite at the core measurement depth points of multiple wells in the study area and the corresponding envelope area, the two parameters a and b in the model were determined by mathematical fitting, where a= -7.3, b= 3.76, and the correlation coefficient of the model reached 0.8934.

[0046] S7. According to the shale vitrinite reflectance logging interpretation model established in step S6, the envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well is calculated according to the compensated neutron and lithology density logging curves of the prediction well, and the calculated envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well is substituted into the shale vitrinite reflectance logging interpretation model established in step S6 to calculate the shale vitrinite reflectance of the prediction well. The calculation method of the envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well is the same as the calculation method of step S5.

[0047] In the actual data processing process, a method for determining the shale vitrinite reflectance based on the neutron-density envelope area is implemented by writing a program. Figure 2 This is a comparison chart of the calculated results of shale vitrinite reflectance and core analysis. According to the process of steps one to five, combined with the geological characteristics of the study area and the logging response law, the compensated neutron linear scale [45, -15] and the lithology density linear scale [1.95, 2.95] are adjusted to overlap the compensated neutron and lithology density logging curves in the sandstone reservoir section (2985-2992m), and the unit area of ​​the compensated neutron and lithology density logging curves is calculated, and then the envelope area of ​​the two is determined. Then, the relationship between the envelope area and the vitrinite reflectance is established by the mathematical fitting method, so as to realize the continuous depth rapid quantitative calculation of the vitrinite reflectance of the predicted well. From the actual data processing results, the calculated results of the vitrinite reflectance are in good agreement with the measured values ​​of the core analysis, which shows the feasibility of this method.

[0048] Example 3 As another preferred embodiment of the present invention, this embodiment provides a device for determining shale vitrinite reflectance based on neutron-density envelope area, the device comprising: a data acquisition module, for acquiring vitrinite reflectance experimental data of core analysis of each well in the study area and well logging curves of the wells corresponding to the core; The logging curve drawing module is used to draw the vitrinite reflectance of the core analysis and the logging curve of the well corresponding to the core on the same graph; The logging curve adjustment module is used to adjust the left and right scales of the neutron and lithology density logging defects so that the neutron and lithology density logging defects are overlapped in the sandstone reservoir section; the logging curve adjustment module provides an adjustment port, and the operator can adjust the left and right scales of the logging curve map drawn by the logging curve drawing module through the logging curve adjustment module according to the geological characteristics of the study area and the logging response law; An envelope area calculation module is used to calculate the envelope area of ​​the compensated neutron and lithology density measurement curves of the wells corresponding to each core; The statistical modeling module conducts statistical analysis on the vitrinite reflectance and corresponding envelope area of ​​core measurement depth points of multiple wells, and establishes a shale vitrinite reflectance logging interpretation model in the study area; The module for calculating the shale vitrinite reflectance in the prediction well obtains the compensated neutron and lithology density logging curves in the prediction well, substitutes them into the shale vitrinite reflectance logging interpretation model established by the statistical modeling module, and calculates the shale vitrinite reflectance in the prediction well.

[0049] Example 4 As another preferred embodiment of the present invention, this embodiment further describes and supplements the technical solution of the present application on the basis of the above-mentioned embodiment 3. In this embodiment, the shale vitrinite reflectance determination device based on the neutron-density envelope area includes a data acquisition module, a logging curve drawing module, a logging curve adjustment module, an envelope area calculation module, a statistical modeling module and a prediction well shale vitrinite reflectance calculation module. The above modules are all functional modules, which can be implemented by programming languages. In the process of programming language implementation, they can be combined with each other according to their functions. The programming languages ​​for implementing the functional modules include but are not limited to C language, C++, python, etc.

[0050] In actual use, shale cores were taken from multiple wells in the study area, and the vitrinite reflectance experimental measurements were performed on the shale cores of each well. The vitrinite reflectance (Ro) experimental data of the core analysis was obtained according to the process specified in the standard "SY / T5124-2012 Method for Determination of Vitrinite Reflectance in Sedimentary Rocks".

[0051] The obtained experimental data of vitrinite reflectance (Ro) of the core analysis of each well and the logging curve data of the well corresponding to the core are input into the device through the data acquisition module. When inputting, the input can be carried out in sequence according to the well number, such as inputting the experimental data of vitrinite reflectance (Ro) of the core analysis of well 1# and its logging curve data, and then inputting the experimental data of vitrinite reflectance (Ro) of the core analysis of well 2# and its logging curve data, and so on. Alternatively, the vitrinite reflectance and logging curve data of the core analysis of each well are packaged and input as a whole. The input method can be automatically received in the form of a data interface, or it can be manually input.

[0052] After completing the data input, the logging curve drawing module draws the vitrinite reflectance of the core analysis and the logging curve of the corresponding well of the core on the same graph, where the logging curve includes the natural gamma (GR) logging curve, the compensated neutron (CNL) logging curve and the lithology density (DEN) logging curve, that is, the vitrinite reflectance of the core analysis and the natural gamma (GR), compensated neutron (CNL) and lithology density (DEN) logging curves of the corresponding well of the core are drawn on the same graph. One well corresponds to one graph, and the processing process of the logging curve drawing module is to process the data in sequence according to the order of the acquired data, or to wait for all the data to be received and then process the data in sequence; or to process them together, which can be determined according to the processing capacity of the hardware equipment.

[0053] The most preferred solution is that the logging curve drawing module displays the vitrinite reflectance of the core analysis in a rod graph (see the attached manual). Figure 2 According to the actual working conditions, the vitrinite reflectance of the core analysis can be displayed in other shapes, such as bar graphs, dot graphs, etc.

[0054] After the logging curve drawing module generates the vitrinite reflectance and logging curve diagram of the core analysis of the well, the logging curve adjustment module adjusts the left and right scales of the compensated neutron and lithology density logging curves in combination with the geological characteristics of the study area and the corresponding logging rules, so that the compensated neutron and lithology density logging curves overlap in the sandstone reservoir section (i.e., the low GR reservoir section) (see the attached manual). Figure 2 The second track (2985-2992m) uses a linear scale for compensated neutrons, with a scale range of [45, -15]; the lithology density uses a linear scale, with a scale range of [1.95, 2.95].

[0055] This function can be realized by the logging curve drawing module, that is, the logging curve drawing module and the logging curve adjustment module are integrated into one functional module.

[0056] The envelope area calculation module uses a one-to-one mapping method to eliminate the difference in physical dimension level between the compensated neutron and lithology density logging curves, calculates the unit area of ​​the compensated neutron and lithology density logging curves, and determines the envelope area of ​​the compensated neutron and lithology density logging curves; Calculate the unit area of ​​the compensated neutron curve, as shown in the attached manual. Figure 2 The 4th CNL_mj curve: , where CNL is the compensated neutron value, %; compensated neutron unit area, dimensionless; Calculate the unit area of ​​the lithology density logging curve, as shown in the attached manual. Figure 2 The fourth DEN_mj curve: , where DEN is the lithology density, g / cm 3 ; Lithology density per unit area, dimensionless; Calculate the envelope area of ​​compensated neutron and lithology density logging curves, as shown in the attached manual. Figure 2 The 4th gray filled part, the 5th to the mjc curve: , where mjc is the envelope area of ​​compensated neutron and lithology density logging curves, dimensionless.

[0057] The statistical modeling module analyzes the relationship between the vitrinite reflectance at the measured depth point of the shale core of each well and the corresponding envelope area, and establishes a logging interpretation model for the vitrinite reflectance of shale in the study area. Specifically, the statistical modeling module conducts statistical analysis on the vitrinite reflectance at the measured depth point of the core of multiple wells and the corresponding envelope area, and establishes a logging interpretation model for the vitrinite reflectance of shale in the study area. The model expression is: , where Ro is the vitrinite reflectance of core analysis; and a and b are model parameters.

[0058] By statistically analyzing the relationship between the vitrinite at the core measurement depth points of multiple wells in the study area and the corresponding envelope area, the two parameters a and b in the model were determined by mathematical fitting, where a= -7.3, b= 3.76, and the correlation coefficient of the model reached 0.8934.

[0059] The prediction well shale vitrinite reflectance calculation module calculates the envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well based on the compensated neutron and lithology density logging curves of the prediction well, substitutes the calculated envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well into the shale vitrinite reflectance logging interpretation model established by the statistical modeling module, and calculates the shale vitrinite reflectance of the prediction well.

[0060] Example 5 As another preferred embodiment of the present invention, in order to achieve the above-mentioned purpose, according to another aspect of the present application, a computer device is also provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the steps of the method for determining the shale vitrinite reflectance based on the neutron-density envelope area described in the above-mentioned embodiment 1 or embodiment 2 are implemented.

[0061] In this embodiment, the processor may be a central processing unit (CPU). The processor may also be 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, or a combination of the above chips.

[0062] The memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer executable programs and units, such as the corresponding program units in the above method embodiments of the present invention. The processor executes various functional applications of the processor and works data processing by running the non-transitory software programs, instructions and modules stored in the memory, that is, implementing the method in the above method embodiments.

[0063] The memory may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created by the processor, etc. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory may optionally include a memory remotely arranged relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0064] The one or more units are stored in the memory, and when executed by the processor, the method in the above-mentioned embodiment 1 or embodiment 2 is executed.

[0065] Example 6 As another preferred embodiment of the present invention, this embodiment discloses a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned embodiment 1 or embodiment 2 are implemented.

Claims

1. A method for determining shale vitrinite reflectance based on neutron-density envelope area, characterized in that: The determination method comprises the following steps: S1. Take shale cores from multiple wells in the study area, conduct vitrinite reflectance experimental measurements on the shale cores of each well, and obtain vitrinite reflectance experimental data for core analysis of each well; S2, obtaining the well logging curve data of the well corresponding to the core of each well in step S1; S3, plotting the vitrinite reflectance of the core analysis obtained in step S1 and the well logging curve of the corresponding well obtained in step S2 on the same graph; S4. In the graph drawn in step S3, the left and right scales of the compensated neutron and lithology density logging curves are adjusted so that the compensated neutron and lithology density logging curves overlap in the sandstone reservoir section; S5, calculating the envelope area of ​​the compensated neutron and lithology density logging curves of the wells corresponding to each core; S6. Analyze the relationship between the vitrinite reflectance at the depth point of the shale core measurement of each well and the corresponding envelope area, and establish a vitrinite reflectance logging interpretation model for shale in the study area; S7. Based on the shale vitrinite reflectance logging interpretation model established in step S6, combined with the compensated neutron and lithology density logging curves in the prediction well, quantitatively calculate the shale vitrinite reflectance in the prediction well.

2. The method for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 1, characterized in that: In step S4, the left and right scales of the compensated neutron and core density logging curves are adjusted. Specifically, the compensated neutron and core density logging curves are both linearly scaled, and the scale range is [CNL L ,CNL R ] and [DEN L ,DEN R ] so that the compensated neutron and core density logging curves overlap in the sandstone reservoir section.

3. A method for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 1 or 2, characterized in that: In step S5, a one-to-one mapping method is used to eliminate the difference in physical dimension level between the compensated neutron and core density logging curves, calculate the unit area of ​​the compensated neutron and core density logging curves, and determine the envelope area of ​​the compensated neutron and lithology density logging curves.

4. The method for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 3, characterized in that: The unit area of ​​the compensated neutron logging curve is: ; In the formula, CNL is the compensated neutron value, %; CNL L To compensate for the neutron left scale end value, CNL R is the right end value of the compensated neutron scale, CNL_mj is the compensated neutron unit area, dimensionless.

5. The method for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 3, characterized in that: The unit area of ​​the lithology density logging curve is: , where DEN is the lithology density, g / cm 3 ;DEN L DWN is the left end value of the lithology density. R is the right end value of the lithology density, DEN_mj is the lithology density per unit area, dimensionless.

6. The method for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 3, characterized in that: The envelope area of ​​the compensated neutron and lithology density logging curve is: , where mjc is the envelope area of ​​compensated neutron and lithology density logging curves, dimensionless; CNL_mj is the compensated neutron unit area, dimensionless; DEN_mj is the lithology density unit area, dimensionless.

7. A method for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 1 or 2, characterized in that: In step S6, the shale vitrinite reflectance at the core measurement depth points of multiple wells and the corresponding envelope area are statistically analyzed to establish a shale vitrinite reflectance logging interpretation model in the study area. The model expression is: , where Ro is the vitrinite reflectance of core analysis; and a and b are model parameters.

8. A method for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 1 or 2, characterized in that: In step S1, the experimental data of vitrinite reflectance of core analysis is obtained according to the process specified in the standard "SY∕T5124-2012 Method for Determination of Vitrinite Reflectance in Sedimentary Rocks".

9. A method for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 1 or 2, characterized in that: In step S3, the vitrinite reflectance of the core analysis and the natural gamma (GR), compensated neutron (CNL) and core density (DEN) logging curves of the corresponding well of the core are plotted on the same graph.

10. The method for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 9, characterized in that: The vitrinite reflectance of the core analysis is displayed as a bar graph.

11. A method for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 1 or 2, characterized in that: In step S7, the compensated neutron and lithology density logging curves in the prediction well are combined, specifically, the envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well is calculated based on the compensated neutron and lithology density logging curves of the prediction well, and the calculated envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well is substituted into the shale vitrinite reflectance logging interpretation model established in step S6 to calculate the shale vitrinite reflectance of the prediction well.

12. A device for determining shale vitrinite reflectance based on neutron-density envelope area, characterized in that: The device includes: The data acquisition module is used to obtain the experimental data of vitrinite reflectance of the core analysis of each well in the study area and the logging curves of the wells corresponding to the core; The logging curve drawing module is used to draw the vitrinite reflectance of the core analysis and the logging curve of the well corresponding to the core on the same graph; The logging curve adjustment module is used to adjust the left and right scales of the compensation neutron and lithology density logging defects so that the compensation neutron and lithology density logging defects overlap in the sandstone reservoir section; An envelope area calculation module is used to calculate the envelope area of ​​the compensated neutron and lithology density measurement curves of the wells corresponding to each core; The statistical modeling module conducts statistical analysis on the vitrinite reflectance and corresponding envelope area of ​​core measurement depth points of multiple wells, and establishes a shale vitrinite reflectance logging interpretation model in the study area; The module for calculating the shale vitrinite reflectance in the prediction well obtains the compensated neutron and lithology density logging curves in the prediction well, substitutes them into the shale vitrinite reflectance logging interpretation model established by the statistical modeling module, and calculates the shale vitrinite reflectance in the prediction well.

13. The device for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 12, characterized in that: In the logging curve adjustment module, adjust the left and right scales of the compensated neutron and core density logging curves. Specifically, the compensated neutron and core density logging curves are both linearly scaled, with a scale range of [CNL L ,CNL R ] and [DEN L ,DEN R ] so that the compensated neutron and core density logging curves overlap in the sandstone reservoir section.

14. The device for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 12 or 13, characterized in that: In the envelope area calculation module, a one-to-one mapping method is used to eliminate the difference in physical dimension level between the compensated neutron and core density logging curves, calculate the unit area of ​​the compensated neutron and core density logging curves, and determine the envelope area of ​​the compensated neutron and lithology density logging curves.

15. The device for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 14, characterized in that: The unit area of ​​the compensated neutron logging curve is: ; In the formula, CNL is the compensated neutron value, %; CNL L To compensate for the neutron left scale end value, CNL R is the right end value of the compensated neutron scale, CNL_mj is the compensated neutron unit area, dimensionless.

16. The device for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 14, characterized in that: The unit area of ​​the lithology density logging curve is: , where DEN is the lithology density, g / cm 3 ;DEN L DWN is the left end value of the lithology density. R is the right end value of the lithology density, DEN_mj is the lithology density per unit area, dimensionless.

17. The device for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 14, characterized in that: The envelope area of ​​the compensated neutron and lithology density logging curve is: , where mjc is the envelope area of ​​compensated neutron and lithology density logging curves, dimensionless; CNL_mj is the compensated neutron unit area, dimensionless; DEN_mj is the lithology density unit area, dimensionless.

18. The device for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 12 or 13, characterized in that: In the statistical modeling module, the shale vitrinite reflectance and the corresponding envelope area at the core measurement depth points of multiple wells are statistically analyzed to establish a shale vitrinite reflectance logging interpretation model in the study area. The model expression is: , where Ro is the vitrinite reflectance of core analysis; and a and b are model parameters.

19. The device for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 12 or 13, characterized in that: In the logging curve drawing module, the vitrinite reflectance of the core analysis and the natural gamma (GR), compensated neutron (CNL) and core density (DEN) logging curves of the corresponding well of the core are drawn on the same graph.

20. The device for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 19, characterized in that: In the logging curve drawing module, the vitrinite reflectance of core analysis is displayed in a rod graph.

21. The device for determining shale vitrinite reflectance based on neutron-density envelope area according to claim 12 or 13, characterized in that: In the prediction well shale vitrinite reflectance calculation module, the envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well is calculated according to the compensated neutron and lithology density logging curves of the prediction well, and the calculated envelope area of ​​the compensated neutron and lithology density logging curves of the prediction well is substituted into the shale vitrinite reflectance logging interpretation model established by the statistical modeling module to calculate the shale vitrinite reflectance of the prediction well.

22. A computer device, characterized in that: The method comprises a processor, an input device, an output device and a memory, wherein the processor, the input device, the output device and the memory are interconnected, wherein the memory is used to store a computer program, the computer program comprises program instructions, and the processor is configured to call the program instructions to execute the method according to any one of claims 1 to 11.

23. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein the computer program includes program instructions, and when the program instructions are executed by a processor, the processor executes the method according to any one of claims 1 to 11.

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