Shale maturity logging prediction method and system and computer equipment

Abstract

According to the shale maturity logging prediction method and system and the computer equipment, the total porosity and the total organic carbon content of shale cores in different areas are analyzed and processed, the mathematical relationship between the relative porosity and the total organic carbon content is obtained, the mathematical relationship reflects the organic matter pore increasing efficiency, and the shale maturity logging prediction accuracy is improved. The pore-increasing efficiency of the organic matters is closely related to the vitrinite reflectivity reflecting the thermal maturity of the organic matters, and the pore-increasing efficiency of the organic matters in the reservoir is reduced along with the increase of the maturity. Therefore, the maturity of the shale reservoir can be predicted and evaluated according to the pore-increasing efficiency of the organic matters, and based on this, a three-parameter chart is established according to the total porosity, the total organic carbon content and the vitrinite reflectance data of the shale in different regions; the mathematical relationship between the relative porosity and the total organic carbon content of the shale reservoir is obtained through data processing of a to-be-detected area, the maturity condition of the organic matter can be judged by combining the three-parameter chart, and reference is provided for reservoir evaluation and prediction.

Description

Technical Field

[0001] The invention relates to the field of organic shale oil and gas reservoir evaluation, and in particular to a shale maturity logging prediction method and system and computer equipment. Background Art

[0002] After years of research and practice, the exploration and development of shale oil and gas reservoirs in my country has explored geological evaluation methods including oil and gas accumulation areas, sweet spots and sweet sections. The sweet sections are shale oil and gas layers with good oil and gas content, superior reservoir conditions, strong transformability and commercial development value under existing economic and technical conditions. The specific evaluation contents are hydrocarbon generation quality, reservoir quality, engineering mechanics quality and oil content.

[0003] From the perspective of the development of logging rock physics evaluation technology, we have experienced the "four properties" relationship analysis of conventional sandstone and mudstone reservoirs, the "seven properties" analysis of tight oil and gas, and medium-shallow shale gas, and then the "reservoir properties", "oil (gas) content", "mobility", and "compressibility" analysis of shale oil and deep shale gas, and carried out the "three qualities" evaluation of logging around the "sweet spot section". The core of reservoir quality evaluation is reservoir properties, and the key is to accurately evaluate the micro-nano pore system of organic-rich mud shale, including the quantitative characterization of porosity and pore structure. The micro-nano pore system greatly affects the reservoir performance, oil and gas occurrence state, and transmission mechanism of mud shale oil and gas; in addition, most of the oil and gas in mud shale reservoirs exist in the pores in the form of adsorption, and accurate pore structure description and evaluation are the key to predicting and developing mud shale oil and gas.

[0004] The pore system of organic-rich shale is mainly composed of organic pores and inorganic mineral matrix pores. The evolution process of its pore system in the geological period is more complicated than that of conventional reservoirs. It is not only affected by diagenesis, but also by the hydrocarbon generation and expulsion of organic matter. Organic matter, as the material basis of organic pores, must have a positive correlation. The thermal evolution maturity of organic matter directly determines the development degree of organic pores. The compaction resistance of inorganic mineral components affects the preservation capacity of organic pores. With the increase of thermal evolution maturity of organic matter, oil-generating pores, gas-generating pores, mechanical compaction of organic pores and even the disappearance of organic pores appear successively. There is still controversy about the mechanism of the influence of organic matter evolution on the inorganic storage space of shale. It may be related to burial history, thermal evolution history, sedimentary environment, etc. at the macro level, and it may be related to the complex structural relationship of shale at the micro level.

[0005] The influence of shale organic matter on reservoir space is reflected in the physical and chemical transformation of the formation during the thermal evolution process, which far exceeds its own contribution to the total pore size. Therefore, clarifying the relationship between organic matter, organic matter thermal maturity and total porosity in shale reservoirs is of great significance for reservoir evaluation and prediction of "sweet spot" areas. Summary of the invention

[0006] In order to solve the above-mentioned problems of the prior art, the present invention provides a shale maturity logging prediction method and system, which reveals the influence mechanism of organic matter on the total porosity of the reservoir during the geological thermal evolution process, and provides a reference for reservoir evaluation and prediction of "sweet spot" areas.

[0007] The present invention is achieved through the following technical solutions:

[0008] A shale maturity logging prediction method, characterized by comprising:

[0009] S1, obtain the total porosity and total organic carbon content of the shale reservoir in the area to be tested through regional logging data;

[0010] S2, establishing a mathematical relationship between the total porosity and the total organic carbon content of the shale reservoir in the test area and performing a translation change through the origin of the coordinate system to obtain a mathematical relationship between the relative porosity and the total organic carbon content of the shale reservoir;

[0011] S3, projecting the mathematical relationship between the relative porosity and total organic carbon content of the shale reservoir onto a three-parameter chart to predict the maturity of the shale reservoir in the test area;

[0012] The three-parameter chart is obtained by the following method: obtaining the total porosity, total organic carbon content and vitrinite reflectance of shale cores in multiple different regions; establishing a mathematical relationship between the total porosity and total organic carbon content of the cores in each region and performing a translation change through the origin of the coordinate system to obtain a mathematical relationship between the relative porosity and total organic carbon content of the cores in each region; using the mathematical relationship between the relative porosity and total organic carbon content in each region and the vitrinite reflectance, a three-parameter chart reflecting the maturity of shale is drawn.

[0013] Preferably, when the total organic carbon content is less than or equal to 2%, the mathematical relationship between the total porosity and the total organic carbon content is as shown in formula (1); when the total organic carbon content is greater than 2%, the mathematical relationship between the total porosity and the total organic carbon content is as shown in formula (2):

[0014]

[0015]

[0016] in, is the total porosity, %, TOC is the total organic carbon content, %, and a1, a2, b1 and b2 are regression coefficients.

[0017] Furthermore, when the total organic carbon content is less than or equal to 2%, the mathematical relationship between the relative porosity and the total organic carbon content is as follows:

[0018]

[0019] When the total organic carbon content is greater than 2%, the mathematical relationship between the relative porosity and the total organic carbon content is as follows:

[0020]

[0021] in, is the relative porosity after translation, %; k is the defined organic matter pore-increasing efficiency.

[0022] Preferably, the plurality of mudstones in different regions include mudstones deposited in marine phases and mudstones deposited in continental phases.

[0023] Preferably, the total porosity, total organic carbon content and vitrinite reflectance of shale cores from multiple different regions are obtained specifically from laboratory test data.

[0024] Preferably, the establishing of the mathematical relationship between the total porosity and the total organic carbon content of the mud shale reservoir in the area to be tested is specifically: drawing an intersection diagram of the total porosity and the total organic carbon content of the mud shale reservoir in the area to be tested, and establishing the mathematical relationship between the total porosity and the total organic carbon content of the mud shale reservoir in the area to be tested according to the intersection diagram;

[0025] The method of establishing the mathematical relationship between the total porosity and the total organic carbon content of the cores in each region specifically comprises drawing a cross-plot of the total porosity and the total organic carbon content of the shale cores in each region, and establishing the mathematical relationship between the total porosity and the total organic carbon content of the cores in each region based on the cross-plot.

[0026] Furthermore, the mathematical relationship between the total porosity and the total organic carbon content of the mud shale reservoir in the test area is established according to the cross-plot. Specifically, the mathematical relationship between the total porosity and the total organic carbon content of the mud shale in the test area is established by performing regression analysis on the cross-plot;

[0027] The mathematical relationship between the total porosity and the total organic carbon content of the cores in each region is established based on the cross-plot. Specifically, regression analysis is performed on the cross-plot to establish the mathematical relationship between the total porosity and the total organic carbon content of the cores in each region.

[0028] Furthermore, the regression analysis is specifically performed using data analysis software.

[0029] A shale maturity logging prediction system, comprising:

[0030] The data acquisition module obtains the total porosity and total organic carbon content of the shale reservoir in the area to be tested through regional logging data;

[0031] The data analysis module establishes the mathematical relationship between the total porosity and the total organic carbon content of the shale reservoir in the test area and translates the relationship through the origin of the coordinate system to obtain the mathematical relationship between the relative porosity and the total organic carbon content of the shale reservoir; the mathematical relationship between the relative porosity and the total organic carbon content of the shale reservoir is projected onto a three-parameter chart to predict the maturity of the shale reservoir in the test area;

[0032] The three-parameter chart is obtained by the following method: obtaining the total porosity, total organic carbon content and vitrinite reflectance of shale cores in multiple different regions; establishing a mathematical relationship between the total porosity and total organic carbon content of the cores in each region and performing a translation change through the origin of the coordinate system to obtain a mathematical relationship between the relative porosity and total organic carbon content of the cores in each region; using the mathematical relationship between the relative porosity and total organic carbon content in each region and the vitrinite reflectance, a three-parameter chart reflecting the maturity of shale is drawn.

[0033] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned shale maturity logging prediction method when executing the computer program.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention obtains the mathematical relationship between relative porosity and total organic carbon content by analyzing and processing the total porosity and total organic carbon content of shale cores in different regions. The mathematical relationship reflects the organic matter pore-increasing efficiency, and finds that the organic matter pore-increasing efficiency is closely related to the vitrinite reflectance reflecting the thermal maturity of organic matter. As the maturity increases, the reservoir organic matter pore-increasing efficiency decreases. Therefore, the maturity of the shale reservoir can be predicted and evaluated according to the organic matter pore-increasing efficiency. Based on this, the present invention establishes a "three-parameter" chart through the total porosity, total organic carbon content, and vitrinite reflectance data of shale in different regions, obtains the mathematical relationship between the relative porosity and total organic carbon content of the shale reservoir through data processing for the tested area, and then combines the "three-parameter" chart to judge the organic matter maturity. The present invention establishes the intrinsic relationship between the total porosity, total organic carbon content, and thermal maturity of the shale reservoir through the analysis of existing experimental data, reveals the mechanism of the influence of organic matter on the total porosity of the reservoir during the geological thermal evolution, and provides a new idea for predicting the thermal maturity of the shale reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 is a flow chart of a shale maturity logging prediction method provided in an embodiment of the present invention;

[0038] Figure 2 It is a mathematical relationship of total porosity and total organic carbon content cross plots and regression analysis of shale reservoirs in five regions provided in the embodiment of the present invention;

[0039] Figure 3 The embodiment of the present invention provides a relationship diagram between relative porosity and TOC after the mathematical expression is translated and changed through the origin when TOC of 5 regions is less than or equal to 2%;

[0040] Figure 4 It is the evaluation and prediction chart of the “three parameters” of relative porosity, total organic carbon content, and vitrinite reflectance provided in the embodiments of the present invention. DETAILED DESCRIPTION

[0041] In order to further understand the present invention, the present invention is described below in conjunction with embodiments. These descriptions are only to further explain the features and advantages of the present invention and are not intended to limit the claims of the present invention.

[0042] See also Figure 1 The shale maturity logging prediction method of the present invention comprises the following steps:

[0043] Step 1, obtaining the total porosity, total organic carbon content and vitrinite reflectance of shale cores from multiple different regions from laboratory test data;

[0044] Step 2, draw the cross plot of total porosity and total organic carbon content of shale cores in each region, and use regression analysis to establish the mathematical relationship between total porosity and total organic carbon content of cores in each region according to the cross plot of total porosity and total organic carbon content of cores. When the total organic carbon content is less than or equal to 2%, the mathematical relationship between total porosity and total organic carbon content of cores is linear. When the total organic carbon content is greater than 2%, the mathematical relationship between total porosity and total organic carbon content of cores is logarithmic, as follows:

[0045]

[0046]

[0047] in, is the total porosity of the core, %, TOC is the total organic carbon content of the corresponding core, % (mass percentage), a1, a2, b1, b2 are regression coefficients;

[0048] Step 3, when TOC is less than or equal to 2%, the linear formula (1) in step 2 is translated through the origin of the coordinate system to obtain the mathematical relationship between relative porosity and total organic carbon content:

[0049]

[0050] When TOC is greater than 2%, the mathematical relationship between relative porosity and total organic carbon content is obtained by translating formula (2) in step 2 through the origin of the coordinate system:

[0051]

[0052] in, is the relative porosity after translation, %;

[0053] Step 4: Define the pore-increasing efficiency of organic matter in shale reservoirs:

[0054]

[0055]

[0056] Among them, Ro is the vitrinite reflectance, %; k is the defined organic matter pore-increasing efficiency, which indicates the increase in reservoir porosity per unit of total organic carbon content, and is closely related to the thermal maturity Ro of organic matter. As the maturity Ro increases, the reservoir organic matter pore-increasing efficiency decreases;

[0057] Step 5, using the mathematical relationship between the relative porosity and the total organic carbon content of the cores in each region and the vitrinite reflectance data, draw the "three-parameter" chart reflecting the organic matter pore-increasing efficiency k and the vitrinite reflectance Ro in step 4;

[0058] Step 6, obtain the total porosity and total organic carbon content of the shale reservoir core in the test area through regional logging data, and use the method of steps 2-3 above to obtain the mathematical relationship between the relative porosity and the total organic carbon content in the test area. According to the mathematical relationship, the maturity of the shale is predicted through the "three parameters" chart, so as to evaluate and predict the favorable shale reservoir in the unknown area.

[0059] The present invention also provides a shale maturity logging prediction system, comprising:

[0060] The data acquisition module obtains the total porosity and total organic carbon content of the shale reservoir in the area to be tested through regional logging data;

[0061] The data analysis module establishes the mathematical relationship between the total porosity and the total organic carbon content of the shale reservoir in the test area and translates the relationship through the origin of the coordinate system to obtain the mathematical relationship between the relative porosity and the total organic carbon content of the shale reservoir; the mathematical relationship between the relative porosity and the total organic carbon content of the shale reservoir is projected onto a three-parameter chart to predict the maturity of the shale reservoir in the test area;

[0062] The three-parameter chart is obtained by the following method: obtaining the total porosity, total organic carbon content and vitrinite reflectance of shale cores in multiple different regions; establishing a mathematical relationship between the total porosity and total organic carbon content of the cores in each region and performing a translation change through the origin of the coordinate system to obtain a mathematical relationship between the relative porosity and total organic carbon content of the cores in each region; using the mathematical relationship between the relative porosity and total organic carbon content in each region and the vitrinite reflectance, a three-parameter chart reflecting the maturity of shale is drawn.

[0063] The present invention also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned shale maturity logging prediction method when executing the computer program.

[0064] Example

[0065] See also Figure 1 The embodiment of the present invention provides a shale maturity logging prediction method, which is operated according to the following steps:

[0066] Step 1: In this embodiment, the total porosity, total organic carbon content, and vitrinite reflectance test data of shale cores from five marine and continental regions at home and abroad are selected.

[0067] Step 2: Create a cross plot between total porosity and total organic carbon content (see Figure 2 ), based on the cross plot between the total porosity and the total organic carbon content of the core, the mathematical relationship between the total porosity and the total organic carbon content in the five regions with a total organic carbon content of less than or equal to 2% and greater than 2% was regressed and the slope and intercept values ​​were determined (see Figure 2 ).

[0068] Step 3: For the cases where TOC is less than or equal to 2% and greater than 2%, the two cases are translated according to the mathematical relationship obtained in step 2. Specifically, the intercept is translated to 0 through the origin of the coordinate system (see Figure 3 ), the following relationship is obtained: in the embodiment, when TOC is less than or equal to 2%, the relative porosity of the five regions is The mathematical expressions of total organic carbon content are as follows:

[0069]

[0070]

[0071]

[0072]

[0073]

[0074] Step 4: Use the mathematical expression obtained in step 3 to combine the vitrinite reflectance of the five regions to draw a "three-parameter" reservoir evaluation and prediction chart of relative porosity, total organic carbon content, and vitrinite reflectance (see Figure 4 ).

[0075] Step 5. For shales in other areas to be tested, the total porosity and total organic carbon content of the shales are obtained through logging data. By implementing steps 2 and 3, the data relationship curve between relative porosity and total organic carbon content can be obtained. The data points on the data relationship curve between relative porosity and total organic carbon content are input into the "three-parameter" reservoir evaluation and prediction chart to determine the organic matter porosity increase efficiency and organic matter maturity, thereby realizing shale reservoir evaluation and favorable reservoir prediction.

[0076] The technical solutions provided in the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A shale maturity logging prediction method, characterized in that: include: S1, obtain the total porosity and total organic carbon content of the shale reservoir in the area to be tested through regional logging data; S2, establishing a mathematical relationship between the total porosity and the total organic carbon content of the shale reservoir in the test area and performing a translation change through the origin of the coordinate system to obtain a mathematical relationship between the relative porosity and the total organic carbon content of the shale reservoir; S3, projecting the mathematical relationship between the relative porosity and total organic carbon content of the shale reservoir onto a three-parameter chart to predict the maturity of the shale reservoir in the test area; The three-parameter chart is obtained by the following method: obtaining the total porosity, total organic carbon content and vitrinite reflectance of shale cores in multiple different regions; establishing a mathematical relationship between the total porosity and total organic carbon content of the cores in each region and performing a translation change through the origin of the coordinate system to obtain a mathematical relationship between the relative porosity and total organic carbon content of the cores in each region; using the mathematical relationship between the relative porosity and total organic carbon content in each region and the vitrinite reflectance, a three-parameter chart reflecting the maturity of shale is drawn.

2. The shale maturity logging prediction method according to claim 1, characterized in that: When the total organic carbon content is less than or equal to 2%, the mathematical relationship between the total porosity and the total organic carbon content is as shown in formula (1); when the total organic carbon content is greater than 2%, the mathematical relationship between the total porosity and the total organic carbon content is as shown in formula (2): in, is the total porosity, %, TOC is the total organic carbon content, %, and a1, a2, b1 and b2 are regression coefficients.

3. The shale maturity logging prediction method according to claim 2, characterized in that: When the total organic carbon content is less than or equal to 2%, the mathematical relationship between the relative porosity and the total organic carbon content is as follows: When the total organic carbon content is greater than 2%, the mathematical relationship between the relative porosity and the total organic carbon content is as follows: in, is the relative porosity after translation, %; k is the defined organic matter pore-increasing efficiency.

4. The shale maturity logging prediction method according to claim 1, characterized in that: The plurality of mudstones in different regions include mudstones deposited in marine phases and mudstones deposited in continental phases.

5. The shale maturity logging prediction method according to claim 1, characterized in that: The total porosity, total organic carbon content and vitrinite reflectance of shale cores from multiple different regions are obtained specifically from laboratory test data.

6. The shale maturity logging prediction method according to claim 1, characterized in that: The method of establishing the mathematical relationship between the total porosity and the total organic carbon content of the shale reservoir in the test area specifically comprises: drawing a cross-plot of the total porosity and the total organic carbon content of the shale reservoir in the test area, and establishing the mathematical relationship between the total porosity and the total organic carbon content of the shale reservoir in the test area according to the cross-plot; The method of establishing the mathematical relationship between the total porosity and the total organic carbon content of the cores in each region specifically comprises drawing a cross-plot of the total porosity and the total organic carbon content of the shale cores in each region, and establishing the mathematical relationship between the total porosity and the total organic carbon content of the cores in each region based on the cross-plot.

7. The shale maturity logging prediction method according to claim 6, characterized in that: The mathematical relationship between the total porosity and the total organic carbon content of the shale reservoir in the test area is established according to the cross-plot. Specifically, the mathematical relationship between the total porosity and the total organic carbon content of the shale in the test area is established by performing regression analysis on the cross-plot; The mathematical relationship between the total porosity and the total organic carbon content of the cores in each region is established based on the cross-plot. Specifically, regression analysis is performed on the cross-plot to establish the mathematical relationship between the total porosity and the total organic carbon content of the cores in each region.

8. The shale maturity logging prediction method according to claim 7, characterized in that: The regression analysis is specifically performed using data analysis software.

9. A shale maturity logging prediction system, characterized in that: include: The data acquisition module obtains the total porosity and total organic carbon content of the shale reservoir in the area to be tested through regional logging data; The data analysis module establishes the mathematical relationship between the total porosity and the total organic carbon content of the shale reservoir in the test area and translates the relationship through the origin of the coordinate system to obtain the mathematical relationship between the relative porosity and the total organic carbon content of the shale reservoir; the mathematical relationship between the relative porosity and the total organic carbon content of the shale reservoir is projected onto a three-parameter chart to predict the maturity of the shale reservoir in the test area; The three-parameter chart is obtained by the following method: obtaining the total porosity, total organic carbon content and vitrinite reflectance of shale cores in multiple different regions; establishing a mathematical relationship between the total porosity and total organic carbon content of the cores in each region and performing a translation change through the origin of the coordinate system to obtain a mathematical relationship between the relative porosity and total organic carbon content of the cores in each region; using the mathematical relationship between the relative porosity and total organic carbon content in each region and the vitrinite reflectance, a three-parameter chart reflecting the maturity of shale is drawn.

10. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the shale maturity logging prediction method according to any one of claims 1 to 8 are implemented.

Images