A method and apparatus for identifying evaporite depositional environments

Abstract

The application discloses a method and device for identifying an evaporite sedimentary environment, and the method comprises the following steps: determining a sedimentary sub-environment of a single well in a study area according to core data and geochemical analysis data of the single well; establishing an environment identification chart according to the determined sedimentary sub-environment, a trace element uranium value in the geochemical analysis data and a logging curve gamma value; and determining an evaporite sedimentary environment of a single well to be identified in the study area according to a logging curve uranium value and a logging curve gamma value of the single well to be identified, and combining the environment identification chart.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil and gas geological exploration, and in particular to a method and device for identifying evaporite sedimentary environment. BACKGROUND

[0002] Evaporite sedimentary system is widely distributed in the world, and important oil and gas discoveries have been made in three major marine basins in China. It is an important field of oil and gas exploration. The research on reservoirs and source rocks of evaporite system is the basis of oil and gas exploration, and the key lies in the identification of sedimentary environment.

[0003] At present, there are many methods for identifying sedimentary environment, such as core observation and geochemical method. However, the above methods have the disadvantages of long analysis time and high application cost.

[0004] Therefore, it is an urgent problem to realize a rapid sedimentary environment identification method. SUMMARY

[0005] The present application provides a method and device for identifying evaporite sedimentary environment. The method is based on the calibration of the sedimentary environment of the coring well by the trace elements in the early stage, the reverse calibration of the U-GR sedimentary environment identification threshold of the logging, and the establishment of the environment identification template based on the logging data to quickly and automatically divide the sedimentary environment.

[0006] In a first aspect, the present application provides a method for identifying evaporite sedimentary environment, comprising:

[0007] determining the sedimentary sub-environment of a single well in the study area according to the core data and geochemical analysis data of the well;

[0008] establishing an environment identification chart according to the sedimentary sub-environment of the well, the trace element uranium value in the geochemical analysis data, and the gamma value of the logging curve;

[0009] determining the evaporite sedimentary environment of a single well to be identified in the study area according to the logging curve uranium value, the logging curve gamma value of the single well to be identified, and the environment identification chart.

[0010] In a second aspect, the present application further provides a device for identifying evaporite sedimentary environment, comprising a memory and a processor; the memory is used to save a program for identifying evaporite sedimentary environment, and the processor is used to read and execute the program for identifying evaporite sedimentary environment, and execute the method of any one of the above embodiments.

[0011] In a third aspect, the present application further provides a computer readable storage medium, wherein the computer readable storage medium stores a data processing program, and the data processing program is executed by a processor to execute the method for identifying evaporite sedimentary environment of any one of the above embodiments.

[0012] Compared with the related art, the application provides a method and device for identifying an evaporite sedimentary environment, the method comprising: determining a sedimentary sub-environment of a single well in a study area according to core data and geochemical analysis data of the well; establishing an environment identification chart according to the sedimentary sub-environment of the well, a trace element uranium value in the geochemical analysis data and a gamma value of a logging curve; and determining an evaporite sedimentary environment of a single well to be identified in the study area according to a uranium value of a logging curve of the single well to be identified, a gamma value of a logging curve of the single well to be identified and the environment identification chart. The application is based on previous calibration of a sedimentary environment of a cored well by trace elements, reverse calibration of a logging U-GR sedimentary environment identification threshold, establishment of an environment identification template based on logging data, and can be widely applied to sedimentary environment identification of evaporite and other marine basins.

[0013] Other features and advantages of the application will be set forth in the following description, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the application. Other advantages of the application can be realized and attained by means of the instrumentalities and combinations particularly pointed out in the description and appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0014] The accompanying drawings are included to provide an understanding of the application scheme, and constitute a part of the specification, and are used together with the embodiments of the application to explain the technical scheme of the application, and do not constitute a limitation on the technical scheme of the application.

[0015] Figure 1 A flow chart of the method for identifying an evaporite sedimentary environment of the embodiments of the application;

[0016] Figure 2 A schematic diagram of the device for identifying an evaporite sedimentary environment of the embodiments of the application;

[0017] Figure 3 A column chart of a sedimentary environment division standard in some exemplary embodiments;

[0018] Figure 4 A logging U-GR environment identification chart in some exemplary embodiments;

[0019] Figure 5 Single well evaporite environment identification and cluster analysis in some exemplary embodiments. DETAILED DESCRIPTION

[0020] This application describes several embodiments, but these descriptions are exemplary and not restrictive, and it will be apparent to those skilled in the art that many more embodiments and implementations are possible within the scope of the embodiments described herein. Although many possible combinations of features are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with, or may replace, any feature or element of any other embodiment.

[0021] This application includes and contemplates combinations of features and elements known to those skilled in the art. The embodiments, features, and elements disclosed in this application may also be combined with any conventional features or elements to form a unique inventive scheme as defined by the claims. Any feature or element of any embodiment may also be combined with features or elements from other inventive schemes to form another unique inventive scheme as defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in this application may be implemented individually or in any suitable combination. Therefore, the embodiments are not limited except by the limitations imposed by the appended claims and their equivalents. Furthermore, various modifications and changes may be made within the scope of the appended claims.

[0022] Furthermore, in describing representative embodiments, the specification may have presented methods and / or processes as a specific sequence of steps. However, the method or process should not be limited to the specific order of steps described herein, to the extent that it does not depend on such a specific order. As will be understood by those skilled in the art, other sequences of steps are also possible. Therefore, the specific order of steps set forth in the specification should not be construed as a limitation of the claims. Moreover, the claims concerning the method and / or process should not be limited to the steps performed in the written order, and those skilled in the art will readily understand that these orders can be varied and still remain within the spirit and scope of the embodiments of this application.

[0023] This invention provides a method for identifying evaporite depositional environments, such as... Figure 1 As shown, the method includes steps S100-S130:

[0024] S100: The sedimentary subenvironment of this well is determined based on core data and geochemical analysis data from a single well in the study area;

[0025] S110: Establish an environmental identification chart based on the sedimentary subenvironment of the well, the trace element uranium values ​​in the geochemical analysis data, and the gamma GR values ​​of the logging curves;

[0026] S120: Determine the evaporite sedimentary environment of each single well according to the logging curves U and the logging curves gamma GR of other single wells in the study area, and in combination with the established environmental identification chart.

[0027] In an example embodiment, the sedimentary sub-environment includes an oxidation section, a sub-oxidation section, and a sulfidation section. In the oxidation section sedimentary sub-environment, the lithology is generally granular or powder crystalline dolomite, the carbon and oxygen isotope values are obviously positive, the U and Mo element contents are low, and the TOC value is low. In the sub-oxidation section sedimentary sub-environment, the lithology is mainly limestone, argillaceous limestone, and cloud spot limestone, the carbon and oxygen isotope values are moderately negative, the U and Mo element contents are moderately low, and the TOC value is moderate. In the sulfidation section sedimentary sub-environment, the lithology is generally gypsum-containing or gypsodolomite, the carbon and oxygen isotope values are moderately low, the U and Mo element contents are high, and the TOC value is high. O

[0028] In an example embodiment, the sedimentary sub-environment of a single well is determined according to the single well with core data and geochemical analysis data in the study area, including:

[0029] First, select a drilling well with full core and geochemical analysis data;

[0030] Second, establish an evaporite sedimentary environment standard column chart, comprehensively analyze the core data and geochemical analysis data, and identify the sedimentary sub-environment; wherein the sedimentary sub-environment includes an oxidation section, a sub-oxidation section, and a sulfidation section;

[0031] Third, establish a matching corresponding relationship between the sedimentary sub-environment and the reservoir and source rock.

[0032] In an example embodiment, the process of establishing an environmental identification chart is:

[0033] First, establish a measured U-GR environmental identification chart according to the trace element uranium value in the geochemical analysis data and the logging curve gamma value;

[0034] In this step, normalize the trace element U value of the test analysis and the logging curve GR value, and establish a measured U-GR intersection environmental identification chart according to the normalized trace element U value and the logging curve GR value;

[0035] Second, establish a logging U-GR environmental identification chart according to the logging curve uranium value and the logging curve gamma value;

[0036] In this step, normalize the logging U value and the GR value, and establish a logging U-GR intersection environmental identification chart according to the normalized logging U value and the GR value;

[0037] ​Thirdly, the measured U-GR environment identification chart is corrected according to the measured U-GR environment identification chart of the well to obtain an environment identification chart.

[0038] In this step, the measured U-GR intersection environment identification chart and the logging U-GR intersection environment identification chart are calibrated by a standard column chart to establish an environment identification chart.

[0039] In an example embodiment, after the establishment of the environment identification chart, a standard threshold corresponding to each sedimentary sub-environment is determined according to the environment identification chart.

[0040] In an example embodiment, the evaporite sedimentary environment of a single well to be identified is determined according to the logging curve U and the logging curve gamma GR of the single well to be identified in the research area, and the established environment identification chart.

[0041] Firstly, a first evaporite sedimentary environment is determined according to the logging curve U and the determined standard threshold.

[0042] Secondly, a second evaporite sedimentary environment is determined according to the logging curve gamma GR and the determined standard threshold.

[0043] Thirdly, a final evaporite sedimentary environment is determined according to the first evaporite sedimentary environment and the second evaporite sedimentary environment.

[0044] In an example embodiment, the process of identifying the sedimentary environment by using the established environment identification chart is as follows:

[0045] I. A threshold is determined according to the established environment identification chart, and the threshold is used as an identification parameter.

[0046] II. The logging curve U and the logging curve gamma GR are automatically input into the identification chart in batches, and clustering analysis is performed to cluster into three levels, i.e., 1 represents an oxidation environment, 2 represents a sub-oxidation environment, and 3 represents a sulfidation environment.

[0047] III. A standard threshold corresponding to each sedimentary sub-environment is determined according to the environment identification chart.

[0048] Secondly, the measured U-GR environment identification chart is corrected according to the measured U-GR environment identification chart of the well to obtain an environment identification chart.

[0049] In a third aspect, the embodiments of the present application further provide a computer readable storage medium, wherein the computer readable storage medium stores a data processing program, and the data processing program is executed by a processor to perform the method for identifying the evaporation rock sedimentary environment according to any one of the above embodiments.

[0050] Example one

[0051] The method for identifying the evaporation rock sedimentary environment in the present application is used to take the Ordovician Majiagou Formation in the Ordos Basin as the research object, and the process of quickly identifying the evaporation rock sedimentary environment is as follows:

[0052] First step, according to the core data and geochemical analysis data of a single well in the research area, the sedimentary sub-environment of the well is determined;

[0053] Step 11. Select T112 well with full coring and geochemical analysis data;

[0054] Step 12. Establish the evaporation rock sedimentary environment standard columnar chart of the Majiagou Formation:

[0055] Step 13. Comprehensive analysis of core and geochemical analysis data (including trace elements, carbon and oxygen isotopes, rare earth elements and other environmental sensitive parameters) to identify the sedimentary sub-environment (oxidation section, sub-oxidation section and sulfidation section);

[0056] Step 14. Establish the matching corresponding relationship between each sedimentary sub-environment and reservoir (porosity development section) and source rock (TOC high value section), as shown in Figure 3

[0057] Second step, establish the environmental identification chart of the Majiagou Formation:

[0058] Step 21. Normalize the trace element U value and the GR value of the logging curve of the Majiagou Formation M4-M5 section, and use the normalized trace element U value and the GR value of the logging curve to establish the measured U-GR intersection environmental identification chart;

[0059] Step 22. Normalize the logging U value and the GR value of the logging curve of the Majiagou Formation, and use the normalized logging U value and the GR value of the logging curve to establish the logging U-GR intersection environmental identification chart;

[0060] Step 23. Calibrate and calibrate the two charts by the evaporation rock environmental standard columnar chart of the Majiagou Formation, establish the environmental identification chart, and determine the standard threshold of the environmental identification chart, as shown in Figure 4 , respectively determine the standard threshold of the logging curve U and the logging curve GR under each sedimentary sub-environment.

[0061] Third step, use the environmental identification chart of the Majiagou Formation to identify the sedimentary environment:

[0062] ​Step 31. The standard threshold of the established environmental identification chart of Majiagou Formation is taken as an identification parameter.

[0063] Step 32. The U and GR logging curves of Majiagou Formation of T59 well are automatically input into the environmental identification chart, and clustering analysis is performed, and clustering is divided into three levels of 1-3. As shown in the figure, 1 represents an oxidation environment, 2 represents a sub-oxidation environment, and 3 represents a sulfidation environment. The oxidation environment corresponds to the dolomite reservoir section, the sulfidation environment generally corresponds to the gypsum section or argillaceous gypsum section, and the source rock is relatively developed. The identification result can effectively support the analysis of source-reservoir configuration relationship and the analysis of late oil and gas reservoir forming conditions. Figure 5

[0064] The method for identifying the sedimentary environment of evaporite rocks realized by the embodiment solves the problems of long analysis time and high cost of application of traditional environmental recovery methods such as core observation and geochemical analysis, and can identify the sedimentary environment of evaporite rocks in batches and automatically after one calibration. The identification time of a single well can be shortened by 10-50 times, and the economic cost is reduced to 5-10% of the original, and the method has good identification effect for high-frequency sequences.

[0065] Those skilled in the art can understand that all or some of the steps in the method disclosed above, the functional modules / units in the system and the device can be implemented as software, firmware, hardware and appropriate combinations thereof. In the hardware implementation, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component can have multiple functions, or one function or step can be performed by several physical components in cooperation. Some or all of the components can be implemented as software executed by a processor such as a digital signal processor or a microprocessor, or as hardware, or as an integrated circuit such as an application-specific integrated circuit. Such software can be distributed on a computer readable medium, which can include computer storage media (or non-transitory media) and communication media (or transitory media). As known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer readable instructions, data structures, program modules or other data, which are implemented in any method or technology. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. In addition, as known to those skilled in the art, communication media generally includes computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and can include any information delivery medium.​

Claims

1. A method of identifying an evaporite depositional environment, characterized by, The method comprises: determining a sedimentary sub-environment of a single well in a study area according to core data and geochemical analysis data of the single well; establishing an environmental identification chart according to the determined sedimentary sub-environment, trace element uranium values in the geochemical analysis data and gamma values of a logging curve; determining an evaporite sedimentary environment of a single well to be identified in the study area according to uranium values of a logging curve, gamma values of a logging curve of the single well to be identified and the environmental identification chart. The sedimentary sub-environment comprises an oxidation section, a sub-oxidation section and a sulfidation section. The environmental identification chart is established according to the determined sedimentary sub-environment, trace element uranium values in the geochemical analysis data and gamma values of a logging curve, and comprises: establishing a measured U-GR environmental identification chart according to the trace element uranium values in the geochemical analysis data and the gamma values of the logging curve; establishing a logging U-GR environmental identification chart according to uranium values of a logging curve and gamma values of a logging curve; correcting the logging U-GR environmental identification chart according to the sedimentary sub-environment of the well, the measured U-GR environmental identification chart, to obtain an environmental identification chart.

2. The method for identifying an evaporite sedimentary environment according to claim 1, wherein the measured U-GR environmental identification chart is established according to the trace element uranium values in the geochemical analysis data and the gamma values of the logging curve, and comprises: normalizing the trace element uranium values in the geochemical analysis data and the gamma values of the logging curve; establishing the measured U-GR environmental identification chart according to the normalized trace element uranium values and the gamma values of the logging curve.

3. The method for identifying an evaporite sedimentary environment according to claim 1, wherein the logging U-GR environmental identification chart is established according to uranium values of a logging curve and gamma values of a logging curve, and comprises: normalizing the uranium values of the logging curve and the gamma values of the logging curve; establishing the logging U-GR environmental identification chart according to the normalized uranium values of the logging curve and the gamma values of the logging curve. After the environmental identification chart is established, the method further comprises: determining a standard threshold value corresponding to each sedimentary sub-environment according to the environmental identification chart.

4. The method of identifying depositional environment of evaporite rocks as claimed in claim 1 wherein, 5. The method for identifying an evaporite sedimentary environment according to claim 4, wherein the evaporite sedimentary environment of the single well to be identified is determined according to uranium values of a logging curve, gamma values of a logging curve of the single well to be identified and the environmental identification chart, and comprises: determining a first evaporite sedimentary environment according to the uranium values of the logging curve of the single well to be identified and the determined standard threshold value; determining a second evaporite sedimentary environment according to the gamma GR of the logging curve of the single well to be identified and the determined standard threshold value; determining a final evaporite sedimentary environment according to the first evaporite sedimentary environment and the second evaporite sedimentary environment.

6. The method for identifying an evaporite sedimentary environment according to claim 5, wherein the first evaporite sedimentary environment is determined according to the uranium values of the logging curve of the single well to be identified and the determined standard threshold value, and comprises: determining the first evaporite sedimentary environment through cluster analysis according to the uranium values of the logging curve of the single well to be identified and the determined standard threshold value. ​ ​ ​ ​ 7. A device for identifying evaporite depositional environments, characterized in that, The device comprises a memory and a processor; the memory is used to save a program for identifying an evaporite rock sedimentary environment, and the processor is used to read and execute the program for identifying the evaporite rock sedimentary environment, and execute the method of any one of claims 1-6. 8.A computer readable storage medium, having a data processing program stored thereon, the data processing program being executed by a processor to perform the method of identifying an evaporite rock sedimentary environment according to any one of claims 1-6.

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