Method and device for calculating mineral content in carbonate rock

Abstract

The invention discloses a method and a device for calculating mineral content in carbonate rocks, which are characterized in that after a logging curve of a to-be-detected object is obtained, the shale content of the to-be-detected object is calculated according to a natural gamma curve in the logging curve, and then the mineral content in the to-be-detected object is calculated according to a photoelectric absorption cross section index and volume density corresponding to a volume density logging curve. And finally, the volume photoelectric absorption cross section index of the to-be-detected object is introduced into the physical volume model of the three mineral rocks, the content of the three minerals in the to-be-detected object is obtained through calculation, the calculation amount is small, the mineral content calculation method is simple, and the rock recognition precision is high.

Description

Technical Field

[0001] The invention relates to the field of resource and environmental technology, and in particular to a method and a device for obtaining the mineral content in carbonate rocks. Background Art

[0002] Carbonate rocks have complex and diverse lithologies, mainly calcite (CaCO 3 ) and dolomite (CaMg(CO 3 ) 2 ) are composed of two carbonate minerals. Carbonate rocks dominated by calcite become limestone, and carbonate rocks dominated by dolomite become dolomite, making it difficult to identify the rock types.

[0003] Carbonate reservoir space is diverse in type, distribution pattern is unclear, and heterogeneity and anisotropy are strong, making carbonate oil and gas exploration and development difficult. In general, the lithology, physical properties, electrical properties and other properties of rocks are used to comprehensively evaluate the quality of carbonate reservoirs. The evaluation is mainly based on the relationship between lithology, physical properties, electrical properties, etc. The relationship between lithology and minerals and reservoir logging response is analyzed, and the logging response characteristics of different rock minerals are clarified. Through core and thin section data, logging intersection plate method, electrical imaging, digital core simulation, etc., rock mineral logging is quantitatively identified, and logging identification plates of different lithology and minerals are established; the relationship between reservoir lithology, physical properties, electrical properties and gas content is analyzed, and the relationship between mineral content, rock characteristics and gas content of carbonate reservoirs is further clarified. Therefore, lithology identification is extremely important in carbonate reservoir evaluation.

[0004] At present, for carbonate rock lithology identification methods, logging is mainly based on on-site cuttings observation, thin section identification under a microscope, X-ray fluorescence element logging and other technologies. Well logging mainly uses photoelectric absorption cross-section index, intersection plate method, electrical imaging and other means to carry out qualitative identification of carbonate rock lithology. Neutron-density complex lithology processing technology calculates the dolomite and limestone content, the calculation process is complex, and requires special processing software, and the calculation cost is high.

[0005] The calculation method in the prior art has the following disadvantages:

[0006] (1) Application No. 201510053573.5, entitled "A method for rapid identification of lithology while drilling in carbonate formations", uses X-ray fluorescence element logging technology to analyze and count the pulse content of Ca and Mg elements to determine limestone and dolomite. However, this method calculates the pulse content, and the calculation process is cumbersome, making it difficult to apply in the field.

[0007] (2) Patent document ZL201610219656.1 entitled “A method for identifying the lithology of sedimentary rocks using element logging” discloses a method for identifying the lithology of sedimentary rocks using element logging. Specifically, the method uses element logging measurement data as parameters and establishes a lithology identification model by analyzing the chemical composition and diagenetic principles of various lithologies, thereby solving the problem of while-drilling lithology identification using element logging. Although this method is suitable for carbonate rocks, the invention has low lithology identification accuracy. Summary of the invention

[0009] The purpose of the present invention is to provide a method and device for calculating the mineral content in carbonate rock. The method for calculating the mineral content is simple and has high accuracy.

[0010] In order to solve the above technical problems, an embodiment of the present invention provides a method for obtaining the mineral content in carbonate rock, comprising:

[0011] S1, obtaining a logging curve of the object to be detected, wherein the logging curve includes a natural gamma curve, a photoelectric absorption cross-section index and a volume density logging curve;

[0012] S2, calculating the mud content of the object to be detected according to the natural gamma curve;

[0013] S3, obtaining a volume photoelectric absorption cross-section index of the object to be detected according to the photoelectric absorption cross-section index and the volume density corresponding to the volume density logging curve, wherein the volume photoelectric absorption cross-section index is: U=PE*DEN, PE is the photoelectric absorption cross-section index, and DEN is the volume density;

[0014] S4, introducing the volume photoelectric absorption cross-section index of the object to be detected into the physical volume model of three mineral rocks, and calculating the contents of the three minerals in the object to be detected, wherein the physical volume model includes:

[0015] U=U maa (1-φ)+U f φ;

[0016] U maa =U A V A +U B V B +U C V C ;

[0017] φ+V A +V B +V C =1;

[0018] Where U is the volume photoelectric absorption cross section index, U maais the rock skeleton volume photoelectric absorption cross-section index, φ is the porosity, U f is the fluid volume photoelectric absorption cross-section index, U A is the volume photoelectric absorption cross section index of mineral A, U B is the volume photoelectric absorption cross section index of mineral B, U C is the volume photoelectric absorption cross section index of mineral C, V A 、V B 、V C It is the relative content of three minerals A, B and C.

[0019] Wherein, after S4, the method further includes:

[0020] A mineral content instruction is received, and after parsing the mineral content instruction, content information of the mineral corresponding to the mineral content instruction is output.

[0021] Wherein, after S4, the method further includes:

[0022] Display the contents of three minerals in the object to be detected or display the content information of the mineral corresponding to the mineral content instruction.

[0023] In addition, the embodiment of the present application also provides a device for obtaining the mineral content in carbonate rock, including:

[0024] A logging curve acquisition module is used to acquire the logging curve of the object to be detected, wherein the logging curve includes a natural gamma curve, a photoelectric absorption cross-section index and a volume density logging curve;

[0025] A shale content calculation module, connected to the logging curve acquisition module, for calculating the shale content of the object to be detected according to the natural gamma curve;

[0026] A total volume photoelectric absorption cross-section index calculation module is connected to the logging curve acquisition module and is used to obtain the volume photoelectric absorption cross-section index of the object to be detected according to the photoelectric absorption cross-section index and the volume density corresponding to the volume density logging curve, wherein the volume photoelectric absorption cross-section index is: U=PE*DEN, PE is the photoelectric absorption cross-section index, and DEN is the volume density;

[0027] The content calculation module is used to introduce the volume photoelectric absorption cross-section index of the object to be detected into the physical volume model of three mineral rocks to calculate the content of the three minerals in the object to be detected, wherein the physical volume model includes:

[0028] U=U maa (1-φ)+U f φ;

[0029] U maa=U A V A +U B V B +U C V C ;

[0030] φ+V A +V B +V C =1;

[0031] Where U is the volume photoelectric absorption cross section index, U maa is the rock skeleton volume photoelectric absorption cross-section index, φ is the porosity, U f is the fluid volume photoelectric absorption cross-section index, U A is the volume photoelectric absorption cross section index of mineral A, U B is the volume photoelectric absorption cross section index of mineral B, U C is the volume photoelectric absorption cross section index of mineral C, V A 、V B 、V C It is the relative content of three minerals A, B and C.

[0032] It also includes a mineral content instruction module connected to the content calculation module, which is used to receive a mineral content instruction and output the content information of the mineral corresponding to the mineral content instruction after parsing the mineral content instruction.

[0033] Among them, it also includes a display module connected to the content calculation module, which is used to display the content of various minerals in the object to be detected.

[0034] It also includes a communication module connected to the content calculation module and the mineral content instruction, which is used to transmit the mineral content instruction and the content information of the mineral corresponding to the mineral content instruction.

[0035] The communication module includes at least one of a WIFI module, a 5G module, and a 4G module.

[0036] The method and device for obtaining the mineral content in carbonate rock provided by the embodiment of the present invention have the following advantages compared with the prior art:

[0037] The method and device for obtaining the mineral content in carbonate rock provided by the embodiment of the present invention calculate the mud content of the object to be detected according to the natural gamma curve after obtaining the logging curve of the object to be detected, and then obtain the volume photoelectric absorption cross-section index of the object to be detected according to the volume density corresponding to the photoelectric absorption cross-section index and the volume density logging curve, and finally introduce the volume photoelectric absorption cross-section index of the object to be detected into the physical volume model of three mineral rocks to calculate the contents of the three minerals in the object to be detected. The calculation amount is small, the method for calculating the mineral content is simple, and the rock recognition accuracy is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A schematic diagram of a flow chart of steps in one embodiment of a method for obtaining the mineral content in carbonate rock provided by the present invention;

[0040] Figure 2 A schematic diagram of the connection structure of an embodiment of the device for obtaining the mineral content in carbonate rock provided by the present invention. DETAILED DESCRIPTION

[0041] 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 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.

[0042] Please refer to Figure 1-2 , Figure 1 A schematic diagram of a flow chart of steps in one embodiment of a method for obtaining the mineral content in carbonate rock provided by the present invention; Figure 2 A schematic diagram of the connection structure of an embodiment of the device for obtaining the mineral content in carbonate rock provided by the present invention.

[0043] In a specific embodiment, the method for obtaining the mineral content in carbonate rock comprises:

[0044] S1, obtaining a logging curve of the object to be detected, wherein the logging curve includes a natural gamma curve, a photoelectric absorption cross-section index and a volume density logging curve;

[0045] S2, calculating the mud content of the object to be detected according to the natural gamma curve;

[0046] S3, obtaining a volume photoelectric absorption cross-section index of the object to be detected according to the photoelectric absorption cross-section index and the volume density corresponding to the volume density logging curve, wherein the volume photoelectric absorption cross-section index is: U=PE*DEN, PE is the photoelectric absorption cross-section index, and DEN is the volume density;

[0047] S4, introducing the volume photoelectric absorption cross-section index of the object to be detected into the physical volume model of three mineral rocks, and calculating the contents of the three minerals in the object to be detected, wherein the physical volume model includes:

[0048] U=U maa (1-φ)+U f φ;

[0049] U maa =U A V A +U B V B +U C V C ;

[0050] φ+V A +V B +V C =1;

[0051] Where U is the volume photoelectric absorption cross section index, U maa is the rock skeleton volume photoelectric absorption cross-section index, φ is the porosity, U f is the fluid volume photoelectric absorption cross-section index, U A is the volume photoelectric absorption cross section index of mineral A, U B is the volume photoelectric absorption cross section index of mineral B, U C is the volume photoelectric absorption cross section index of mineral C, V A 、V B 、V C It is the relative content of three minerals A, B and C.

[0052] After obtaining the logging curve of the object to be detected, the mud content of the object to be detected is calculated according to the natural gamma curve therein, and then the volume photoelectric absorption cross-section index of the object to be detected is obtained according to the volume density corresponding to the photoelectric absorption cross-section index and the volume density logging curve. Finally, the volume photoelectric absorption cross-section index of the object to be detected is introduced into the physical volume model of three mineral rocks to calculate the contents of the three minerals in the object to be detected. The calculation amount is small, the method for calculating the mineral content is simple, and the rock recognition accuracy is high.

[0053] Although the content information of three minerals can be obtained in the present application, in actual operation, not all the information is necessarily required. Therefore, in order to directly obtain the required specified content, in one embodiment, after S4, the following is further included:

[0054] A mineral content instruction is received, and after parsing the mineral content instruction, content information of the mineral corresponding to the mineral content instruction is output.

[0055] By receiving a mineral content instruction and, after parsing the mineral content instruction, outputting the content information of the mineral corresponding to the mineral content instruction, the required data can be directly obtained. In this way, there is no need to add the output of the mineral type in the transmission information. Therefore, only the content data needs to be output, and the data transmission volume is relatively small.

[0056] For example, before the mineral content instruction is parsed, the content of all minerals needs to be listed, the amount of data is large, and even the corresponding mineral types need to be marked. In the embodiment of the present application, data is directly output, and the staff can determine the data type.

[0057] In order to obtain the output information, after S4, the following steps are further included:

[0058] Display the contents of three minerals in the object to be detected or display the content information of the mineral corresponding to the mineral content instruction.

[0059] By displaying the contents of the three minerals outputted or displaying the content information of the minerals corresponding to the mineral content instructions, the specific data therein can be directly read.

[0060] It should be pointed out that the display of the contents of the three minerals in the object to be detected or the display of the mineral content information corresponding to the mineral content instruction in the present application can be displayed using a dedicated display or can be displayed via remote data transmission to a mobile electronic terminal such as a user's mobile phone.

[0061] In one embodiment, the device for obtaining the mineral content in carbonate rock comprises the following steps:

[0062] 1) Obtaining well logging curves of the target work area, wherein the well logging curves include natural gamma curves, photoelectric absorption cross-section index and volume density well logging curves;

[0063] 2) According to the rock photoelectric absorption cross-section index and volume density, the rock volume photoelectric absorption cross-section index is obtained; the corresponding volume photoelectric absorption cross-section index is: U = PE*DEN, PE is the photoelectric absorption cross-section index, and DEN is the volume density;

[0064] 3) The rock volume photoelectric absorption cross-section index is introduced into the rock physical volume model of the three minerals to calculate the content of any one of the three minerals.

[0065] Among them, U=U maa (1-φ)+U f φ;

[0066] U maa =U A V A +U B V B +U C V C ;

[0067] φ+V A +V B +V C =1;

[0068] Where U is the volume photoelectric absorption cross section index, U maa is the rock skeleton volume photoelectric absorption cross-section index, φ is the porosity, U f is the fluid volume photoelectric absorption cross-section index, U A is the volume photoelectric absorption cross section index of mineral A, U B is the volume photoelectric absorption cross section index of mineral B, U C is the volume photoelectric absorption cross section index of mineral C, V A 、V B 、V C It is the relative content of three minerals A, B and C.

[0069] Furthermore, in the absence of pores, the rock volume model formula is used to deduce the mineral B content as:

[0070]

[0071] Furthermore, the calculation method of the content of carbonate mineral B is that if A is calcite, B is dolomite, and C is a clay mineral, then the content of dolomite is:

[0072]

[0073] Where U lime is the volume photoelectric absorption cross section index of calcite, U dolo is the volume photoelectric absorption cross-section index of dolomite, Uc is the volume photoelectric absorption cross-section index of clay minerals, and Vc is the clay content.

[0074] Through the natural gamma curve obtained from logging, the mud content is calculated, and the photoelectric absorption cross-section index and volume density are obtained. The photoelectric absorption cross-section index is multiplied by the volume density to obtain the volume photoelectric absorption cross-section index. The volume photoelectric absorption cross-section index is introduced into the rock physics model to obtain the dolomite volume content. The calculated results are compared with the X-ray diffraction experimental data, and the correlation reaches 92%, which makes this method highly feasible and has broad promotion value.

[0075] The following is the well logging curve data and mineral content data in one embodiment:

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082] In addition, the embodiment of the present application also provides a device for obtaining the mineral content in carbonate rock, including:

[0083] The logging curve acquisition module 10 is used to acquire the logging curve of the object to be detected, wherein the logging curve includes a natural gamma curve, a photoelectric absorption cross-section index and a volume density logging curve;

[0084] A shale content calculation module 20, connected to the logging curve acquisition module, is used to calculate the shale content of the object to be detected according to the natural gamma curve;

[0085] The total volume photoelectric absorption cross-section index calculation module 30 is connected to the logging curve acquisition module, and is used to obtain the volume photoelectric absorption cross-section index of the object to be detected according to the photoelectric absorption cross-section index and the volume density corresponding to the volume density logging curve, wherein the volume photoelectric absorption cross-section index is: U=PE*DEN, PE is the photoelectric absorption cross-section index, and DEN is the volume density;

[0086] The content calculation module 40 is used to introduce the volume photoelectric absorption cross-section index of the object to be detected into the physical volume model of three mineral rocks to calculate the content of the three minerals in the object to be detected, wherein the physical volume model includes:

[0087] U=U maa (1-φ)+U f φ;

[0088] U maa =U A V A +U B V B +U C V C ;

[0089] φ+V A +V B +V C =1;

[0090] Where U is the volume photoelectric absorption cross section index, U maa is the rock skeleton volume photoelectric absorption cross-section index, φ is the porosity, U f is the fluid volume photoelectric absorption cross-section index, U A is the volume photoelectric absorption cross section index of mineral A, U B is the volume photoelectric absorption cross section index of mineral B, U C is the volume photoelectric absorption cross section index of mineral C, V A 、V B 、V C It is the relative content of three minerals A, B and C.

[0091] Since the device for obtaining the mineral content in carbonate rock is a device corresponding to the above-mentioned method for obtaining the mineral content in carbonate rock, and has the same beneficial effects, this application will not elaborate on it.

[0092] In order to further implement the specificity of data output, reduce the transmission of invalid data, and improve the transmission and utilization efficiency of data, in one embodiment, the device for obtaining the mineral content in carbonate rock also includes a mineral content instruction module connected to the content calculation module, which is used to receive a mineral content instruction, and after parsing the mineral content instruction, output the content information of the mineral corresponding to the mineral content instruction.

[0093] By providing a mineral content instruction module, which is used to receive a mineral content instruction and output the content information of the mineral corresponding to the mineral content instruction after parsing the mineral content instruction, the transmission efficiency and utilization efficiency of data are improved.

[0094] In order to further improve the efficiency of data use, in one embodiment, the device for obtaining the mineral content in carbonate rock further includes a display module connected to the content calculation module, which is used to display the content of various minerals in the object to be detected.

[0095] The display module is used to display the contents of various minerals in the object to be detected, thereby enabling real-time reading of various data.

[0096] This application does not limit the type of display module and display type.

[0097] To update a step further, in order to achieve efficient data transmission, in one embodiment, the device for obtaining the mineral content in carbonate rock also includes a communication module connected to the content calculation module and the mineral content instruction, for transmitting the mineral content instruction and the content information of the mineral corresponding to the mineral content instruction.

[0098] By transmitting the mineral content instruction and the mineral content information corresponding to the mineral content instruction through the communication module, the user can use a smaller device to directly transmit data, thereby improving the efficiency and flexibility of data utilization.

[0099] The present application does not limit the type of communication module, and the communication module includes at least one of a WIFI module, a 5G module, and a 4G module.

[0100] The device for obtaining the mineral content in carbonate rock obtains the photoelectric absorption cross-section index and the volume density through well logging, multiplies the photoelectric absorption cross-section index by the volume density to obtain the volume photoelectric absorption cross-section index, obtains the mud content through natural gamma curve calculation, introduces the mud content and the volume photoelectric absorption cross-section index into a rock physics model, and obtains the dolomite volume content. It does not need to obtain a large amount of well logging data, which can not only reduce costs but also quickly and accurately calculate the dolomite content, and has a relatively wide range of application value.

[0101] In summary, the method and device for obtaining the mineral content in carbonate rock provided by the embodiment of the present invention calculate the mud content of the object to be detected according to the natural gamma curve after obtaining the logging curve of the object to be detected, and then obtain the volume photoelectric absorption cross-section index of the object to be detected according to the volume density corresponding to the photoelectric absorption cross-section index and the volume density logging curve. Finally, the volume photoelectric absorption cross-section index of the object to be detected is introduced into the physical volume model of the three mineral rocks to calculate the contents of the three minerals in the object to be detected. The calculation amount is small, the method for calculating the mineral content is simple, and the rock identification accuracy is high.

[0102] The above is a detailed introduction to the method and device for obtaining the mineral content in carbonate rocks provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for obtaining the mineral content in carbonate rock, characterized in that: include: S1, obtaining a logging curve of the object to be detected, wherein the logging curve includes a natural gamma curve, a photoelectric absorption cross-section index and a volume density logging curve; S2, calculating the mud content of the object to be detected according to the natural gamma curve; S3, obtaining a volume photoelectric absorption cross-section index of the object to be detected according to the photoelectric absorption cross-section index and the volume density corresponding to the volume density logging curve, wherein the volume photoelectric absorption cross-section index is: U=PE*DEN, PE is the photoelectric absorption cross-section index, and DEN is the volume density; S4, introducing the volume photoelectric absorption cross-section index of the object to be detected into the physical volume model of three mineral rocks, and calculating the contents of the three minerals in the object to be detected, wherein the physical volume model includes: U=U maa (1-φ)+U f φ; U maa =U A V A +U B V B +U C V C ; φ+V A +V B +V C =1; Where U is the volume photoelectric absorption cross section index, U maa is the rock skeleton volume photoelectric absorption cross-section index, φ is the porosity, U f is the fluid volume photoelectric absorption cross-section index, U A is the volume photoelectric absorption cross section index of mineral A, U B is the volume photoelectric absorption cross section index of mineral B, U C is the volume photoelectric absorption cross section index of mineral C, V A 、V B 、V C It is the relative content of three minerals A, B and C.

2. The method for determining the mineral content in carbonate rock according to claim 1, characterized in that: After S4, the method further includes: A mineral content instruction is received, and after parsing the mineral content instruction, content information of the mineral corresponding to the mineral content instruction is output.

3. The method for obtaining the mineral content in carbonate rock according to claim 2, characterized in that: After S4, the method further includes: Display the contents of three minerals in the object to be detected or display the content information of the mineral corresponding to the mineral content instruction.

4. A device for determining the mineral content in carbonate rock, characterized in that: include: A logging curve acquisition module is used to acquire the logging curve of the object to be detected, wherein the logging curve includes a natural gamma curve, a photoelectric absorption cross-section index and a volume density logging curve; A shale content calculation module, connected to the logging curve acquisition module, for calculating the shale content of the object to be detected according to the natural gamma curve; A total volume photoelectric absorption cross-section index calculation module is connected to the logging curve acquisition module and is used to obtain the volume photoelectric absorption cross-section index of the object to be detected according to the photoelectric absorption cross-section index and the volume density corresponding to the volume density logging curve, wherein the volume photoelectric absorption cross-section index is: U=PE*DEN, PE is the photoelectric absorption cross-section index, and DEN is the volume density; The content calculation module is used to introduce the volume photoelectric absorption cross-section index of the object to be detected into the physical volume model of three mineral rocks to calculate the content of the three minerals in the object to be detected, wherein the physical volume model includes: U=U maa (1-φ)+U f φ; U maa =U A V A +U B V B +U C V C ; φ+V A +V B +V C =1; Where U is the volume photoelectric absorption cross section index, U maa is the rock skeleton volume photoelectric absorption cross-section index, φ is the porosity, U f is the fluid volume photoelectric absorption cross-section index, U A is the volume photoelectric absorption cross section index of mineral A, U B is the volume photoelectric absorption cross section index of mineral B, U C is the volume photoelectric absorption cross section index of mineral C, V A 、V B 、V C It is the relative content of three minerals A, B and C.

5. The device for determining the mineral content in carbonate rock according to claim 4, characterized in that: It also includes a mineral content instruction module connected to the content calculation module, which is used to receive a mineral content instruction and output the content information of the mineral corresponding to the mineral content instruction after parsing the mineral content instruction.

6. The method for determining the mineral content in carbonate rock according to claim 5, characterized in that: It also includes a display module connected to the content calculation module, which is used to display the content of various minerals in the object to be detected.

7. The method for determining the mineral content in carbonate rock according to claim 6, characterized in that: It also includes a communication module connected to the content calculation module and the mineral content instruction, and is used to transmit the mineral content instruction and the content information of the mineral corresponding to the mineral content instruction.

8. The method and device for determining the mineral content in carbonate rock according to claim 7, characterized in that: The communication module includes at least one of a WIFI module, a 5G module, and a 4G module.

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