Method for rapidly evaluating mobility of interlayer type shale oil

Abstract

The invention discloses a method for rapidly evaluating mobility of interlayer type shale oil. The method is specifically implemented according to the following steps: step 1, selecting different types of interlayer type shale oil reservoir rock samples; 2, analyzing oil gas components of the sample selected in the step 1, and calculating the movable oil quantity; step 3, acquiring geological factors of the sample selected in the step 1, which influence the mobility of the interlayer type shale oil; 4, establishing a sandwich type shale oil mobility quantitative evaluation model based on multiple regression; 5, the geological factors, influencing the mobility of the interlayer type shale oil, of the to-be-evaluated target are substituted into the model in the step 4, and the movable oil quantity of the interlayer type shale oil of the to-be-evaluated target is obtained. The method solves the problem that an existing method is long in evaluation period.

Description

Technical Field

[0001] The present invention belongs to the technical field of unconventional oil and gas exploration, and in particular relates to a method for rapidly evaluating the mobility of interlayer shale oil. Background Art

[0002] Shale oil is an important part of global oil and gas resources in the 21st century. In recent years, China has made continuous breakthroughs in shale oil and gas exploration and development. Large-scale shale oil and gas resources have been discovered in the Paleogene Shahejie Formation in the Bohai Bay Basin, the Cretaceous Qingshankou Formation in the Songliao Basin, and the Upper Triassic Yanchang Formation in Ordos. In 2022, the shale oil production in Ordos exceeded 210×10 4 t, shale oil will be an important guarantee for China's stable and increased oil and gas production. According to geological conditions and sedimentary characteristics, China's continental shale reservoir "sweet spots" can be divided into three categories: interlayer type, mixed accumulation type, and shale type. Among them, interlayer shale oil is widely distributed in freshwater lake basins such as the Ordos Basin and the Sichuan Basin, and has great exploration potential. Interlayer shale oil usually refers to the oil that has not been migrated and accumulated over long distances in the tight sandstone and shale sandwiched in the source rock formation. It has complex characteristics such as source-reservoir symbiosis, large-area continuous distribution, near-source high-pressure injection of oil and gas, or in-situ retention, which leads to large differences in the occurrence state and mobility characteristics of interlayer shale oil.

[0003] Interlayer shale oil exists in the pore space of tight reservoirs in two states: free oil (mobile oil) and adsorbed oil (immobile oil). Free oil is often found in microcracks and larger pores. It refers to the part of oil that can flow in the reservoir and can be produced from the oil layer under current technical conditions. It is the main contributor to production capacity. Adsorbed oil (immobile oil) is mainly adsorbed in small pores and on the surface of minerals and kerogen. It refers to the part of oil that does not flow and is difficult to produce in the reservoir under current technical conditions. The oil content index in actual sweet spot prediction usually refers to the free movable oil content. Therefore, clarifying the mobility of interlayer shale oil under complex geological conditions is the key to current research on interlayer shale oil, which is of great significance to the exploration and development of interlayer shale oil reserves and effective utilization.

[0004] Although there are literature reports on the evaluation methods of the mobility of interlayer shale oil in reservoir rocks, such as (1) Wu Liyan, Zhang Zhenling, Ma Wenling "Quantitative Analysis Method of Oil and Gas Components in Reservoir Rocks" (Logging Technology, Issue 3, 2000), which used rock pyrolysis experiments to obtain gasoline, kerosene, diesel, wax, and heavy oil fractions in the reservoir, and quantitatively characterized the characteristics of the movable oil content in the tight reservoir; (2) Jiang Qigui, Li Maowen, Qian Menhui, Li Zhiming, Li Zheng, Huang Zhenkai, Zhang Caiming, Ma Yuanyuan "Quantitative Characterization Technology and Application Research of Shale Oil in Different Occurrence States" (Petroleum Experimental Geology , 2016, No. 6), in which the Rock-Eval pyrolysis and pyrolysis chromatography methods were improved, combined with the sample solvent extraction before and after the pyrolysis comparison experiment and the comprehensive analysis of different types of samples, a quantitative characterization method of shale oil in different occurrence states was established by thermal release method; (3) Sang Qian, Zhang Shaojie, Zhu Chaofan, Dong Mingzhe, Li Yajun "Nuclear Magnetic Resonance Study of Movable Fluids in Continental Shale Oil Reservoirs" (China Science and Technology Papers, 2017, No. 9), in which the movable fluid test was carried out by nuclear magnetic resonance technology to characterize the mobility of fluids in continental shale oil reservoir rock samples. However, although these experimental methods can obtain more accurate mobility characteristics of interlayer shale oil, their evaluation cycle is relatively long. Summary of the invention

[0005] The purpose of the present invention is to provide a method for quickly evaluating the mobility of interlayer shale oil, thereby solving the problem of long evaluation cycle of existing methods.

[0006] The technical solution adopted by the present invention is a method for quickly evaluating the mobility of interlayer shale oil, which is specifically implemented according to the following steps:

[0007] Step 1, selecting different types of interlayer shale oil reservoir rock samples;

[0008] Step 2, analyzing the oil and gas components of the sample selected in step 1 and calculating the movable oil volume;

[0009] Step 3, obtaining geological factors affecting the mobility of interlayer shale oil from the samples selected in step 1;

[0010] Step 4, establishing a quantitative evaluation model for the mobility of interlayer shale oil based on multivariate regression;

[0011] Step 5, substitute the geological factors affecting the mobility of interlayer shale oil of the target to be evaluated into the model of step 4 to obtain the movable oil volume of interlayer shale oil of the target to be evaluated.

[0012] The present invention is also characterized in that:

[0013] In step 2, the oil and gas components are analyzed by pyrolysis experiment. The specific process is: the natural gas S is tested at a constant temperature of 90°C for 2 minutes. 0 , test the gasoline content S at 200℃ for 1min1 Then the temperature was raised to 350℃ at a rate of 50℃ / min and kept constant for 1min to test the kerosene and diesel content S 21 Then, the temperature was raised to 450℃ at a rate of 50℃ / min and kept constant for 1min to test the wax content S 22 Then the temperature was raised to 600℃ at a rate of 50℃ / min and kept at this temperature for 1min to test the content of heavy hydrocarbons and colloidal asphaltene. 23 .

[0014] In step 2, movable oil volume = S 1 +S 21 .

[0015] In step 3, the geological factors that affect the mobility of interlayer shale oil include reservoir rock single layer thickness, reservoir rock porosity, reservoir rock average pore size, shale single layer thickness and shale total organic carbon content.

[0016] The thickness of a single layer of reservoir rock is determined by logging data and lithological interpretation of well logging; the porosity of reservoir rock is directly obtained based on pore-permeability test experiments; the average pore size of reservoir rock is obtained by high-pressure mercury injection experiment; the thickness of a single layer of shale is determined by logging data and lithological interpretation of well logging; and the total organic carbon content is obtained by experimental analysis.

[0017] The quantitative evaluation model of interlayer shale oil mobility based on multivariate regression is: Movable oil volume = b 0 +b 1 *H sand +b 2 *Por+b 3 *R a +b 4 *H shale +b 5 *TOC;

[0018] In the formula, H sand is the single layer thickness of reservoir rock; Por is the porosity of reservoir rock; R a is the average pore size of reservoir rock; H shale is the thickness of a shale layer; TOC is the total organic carbon content of shale; b 0 、b 1 、b 2 、b 3 、b 4 、b 5 are the model parameters obtained from multiple regression.

[0019] SPSS software was used to perform multiple regression analysis and the H obtained in step 3 was sand , Por, R a , H shale, select the TOC variable into the independent variable box, select the movable oil volume obtained in step 2 into the dependent variable box, and obtain b 0 、b 1 、b 2 、b 3 、b 4 、b 5 .

[0020] The beneficial effects of the present invention are:

[0021] (1) The method for rapidly evaluating the mobility of interlayer shale oil of the present invention integrates multiple factors that may affect the mobility of interlayer shale oil and converts them into quantitative information. A quantitative evaluation model is established using a multivariate regression method, thereby enhancing the accuracy of the mobility evaluation.

[0022] (2) The method of the present invention for rapidly evaluating the mobility of interlayer shale oil can establish a multiple regression quantitative evaluation model for the mobility of interlayer shale oil in a short period of time through the multiple regression method, thereby improving efficiency and saving time. Compared with the previous evaluation method based entirely on experimental testing, it has stronger applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of a method for rapidly evaluating the mobility of interlayer shale oil according to the present invention;

[0024] Figure 2 This is a quantitative analysis spectrum of oil and gas components in Example 3 of the present invention;

[0025] Figure 3 is the corresponding relationship between the single layer thickness of the reservoir rock and the movable oil volume in Example 3 of the present invention;

[0026] Figure 4 The corresponding relationship between the porosity and the movable oil amount in Example 3 of the present invention;

[0027] Figure 5 is the corresponding relationship between the average pore diameter and the movable oil amount in Example 3 of the present invention;

[0028] Figure 6 The corresponding relationship between the thickness of the shale single layer and the amount of movable oil in Example 3 of the present invention;

[0029] Figure 7 is the corresponding relationship between the total organic carbon content and the movable oil amount in Example 3 of the present invention;

[0030] Figure 8 The relationship between the movable oil volume modeled in Example 3 of the present invention and the multiple regression movable oil volume result fitting;

[0031] Fig. 9This is the fitting relationship between the measured movable oil volume in region J of the embodiment of the present invention and the movable oil volume evaluation result of multiple regression. DETAILED DESCRIPTION

[0032] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] The method for rapidly evaluating the mobility of interlayer shale oil of the present invention is as follows: Figure 1 As shown, the specific implementation steps are as follows:

[0035] Step 1: Select different types of interlayer shale oil reservoir rock samples. The selected samples need to cover the geological factors that affect the mobility of interlayer shale oil, including reservoir rock single layer thickness, reservoir rock porosity, reservoir rock average pore size, shale single layer thickness and total organic carbon content characteristics;

[0036] Step 2, analyzing the oil and gas components of the sample selected in step 1 and calculating the movable oil volume;

[0037] Step 3, obtaining geological factors affecting the mobility of interlayer shale oil from the samples selected in step 1;

[0038] Step 4, establishing a quantitative evaluation model for the mobility of interlayer shale oil based on multivariate regression;

[0039] Step 5, substitute the geological factors affecting the mobility of interlayer shale oil of the target to be evaluated into the model of step 4 to obtain the movable oil volume of interlayer shale oil of the target to be evaluated.

[0040] Example 2

[0041] The method for rapidly evaluating the mobility of interlayer shale oil of the present invention is specifically implemented according to the following steps:

[0042] Step 1: Select different types of interlayer shale oil reservoir rock samples. The selected samples need to cover the geological factors that affect the mobility of interlayer shale oil, including reservoir rock single layer thickness, reservoir rock porosity, reservoir rock average pore size, shale single layer thickness and total organic carbon content characteristics;

[0043] Step 2, analyzing the oil and gas components of the sample selected in step 1, and calculating the movable oil volume (free oil volume);

[0044] The analysis of oil and gas components is carried out by pyrolysis experiment. The specific process is as follows: the natural gas S is tested at a constant temperature of 90°C for 2 minutes. 0 Then the temperature was raised to 200℃ at a rate of 50℃ / min and kept at 200℃ for 1min to test the gasoline content S 1Then the temperature was raised to 350℃ at a rate of 50℃ / min and kept constant for 1min to test the kerosene and diesel content S 21 Then, the temperature was raised to 450℃ at a rate of 50℃ / min and kept constant for 1min to test the wax content S 22 Then the temperature was raised to 600℃ at a rate of 50℃ / min and kept at this temperature for 1min to test the content of heavy hydrocarbons and colloidal asphaltene. 23 ;

[0045] Movable oil volume = S 1 +S 21 ; Amount of adsorbed hydrocarbons = S 22 +S 23 ; Total oil in reservoir rock = S 1 +S 21 +S 22 +S 23 ;

[0046] Step 3, obtaining geological factors affecting the mobility of interlayer shale oil from the samples selected in step 1;

[0047] The geological factors that affect the mobility of interlayer shale oil include reservoir rock single layer thickness, reservoir rock porosity, reservoir rock average pore size, shale single layer thickness and shale total organic carbon content;

[0048] The thickness of a single layer of reservoir rock is determined by logging data and logging lithology interpretation; the porosity of reservoir rock is directly obtained based on pore permeability test experiments, and when the available measured data is relatively limited, it can be indirectly obtained by logging calculation, specifically using Archie's formula, which is known to those skilled in the art; the average pore size of reservoir rock is obtained by high-pressure mercury injection experiment; the thickness of a single layer of shale is determined by logging data and logging lithology interpretation; the total organic carbon content is obtained by experimental analysis, which is a conventional technology in the field, and is known to those skilled in the art, and when the available measured TOC data is relatively limited, it can be indirectly determined by calculation and prediction based on the logging ΔlogR method;

[0049] Step 4: According to the movable oil volume obtained in step 2 and the geological factors obtained in step 3, a quantitative evaluation model for the mobility of interlayer shale oil based on multiple regression is established, with the geological factors as independent variables and the movable oil volume (free oil volume) as dependent variables;

[0050] The quantitative evaluation model of interlayer shale oil mobility based on multivariate regression is:

[0051] Movable oil volume = b 0 +b 1 *H sand +b 2 *Por+b 3 *R a +b4 *H shale +b 5 *TOC;

[0052] In the formula, H sand is the single-layer thickness of reservoir rock; Por is the porosity of reservoir rock; R a is the average pore size of reservoir rock; H shale is the thickness of a shale layer; TOC is the total organic carbon content of shale; b 0 , b 1 , b 2 , b 3 , b 4 , b 5 are the model parameters obtained from multiple regression,

[0053] SPSS software was used to perform multiple regression analysis and the H obtained in step 3 was sand , Por, R a , H shale , select the TOC variable into the independent variable box, select the movable oil volume obtained in step 2 into the dependent variable box, and obtain b 0 , b 1 , b 2 , b 3 , b 4 , b 5 ;

[0054] Step 5, substitute the geological factors affecting the mobility of interlayer shale oil of the target to be evaluated into the model of step 4 to obtain the movable oil volume of the interlayer shale oil of the target to be evaluated, that is, determine the mobility characteristics of the interlayer shale oil of the evaluation target.

[0055] Example 3

[0056] Sampling and analysis of well number Z1-A-1 was carried out in the following steps:

[0057] Step 1: Collect different types of interlayer shale oil reservoir rock samples in the study area. The samples cover a variety of geological conditions that affect mobility, including reservoir rock single layer thickness, reservoir rock porosity, reservoir rock average pore size, shale single layer thickness and total organic carbon content characteristics;

[0058] Step 2: Conduct reservoir rock pyrolysis experimental analysis on the samples from step 1, and use Rock-Eval pyrolysis instrument to quantitatively analyze the oil and gas components in the reservoir rock. The specific process is: test the natural gas S at a constant temperature of 90°C for 2 minutes. 0 , test the gasoline content S at 200℃ for 1min 1 Then the temperature was raised to 350℃ at a rate of 50℃ / min and kept constant for 1min to test the kerosene and diesel content S 21Then, the temperature was raised to 450℃ at a rate of 50℃ / min and kept constant for 1min to test the wax content S 22 Then the temperature was raised to 600℃ at a rate of 50℃ / min and kept at this temperature for 1min to test the content of heavy hydrocarbons and colloidal asphaltene. 23 ; Then calculate the movable oil volume, and the quantitative analysis spectrum of oil and gas components in the reservoir rock is shown in Table 1 and Figure 2 As shown;

[0059] Table 1 Oil and gas components of well number Z1-A-1 with analysis period = 1

[0060] Analysis No. quality <![CDATA[S 0 ]]> <![CDATA[S 1 ]]> <![CDATA[S 21 ]]> <![CDATA[S 22 ]]> <![CDATA[S 23 ]]> <![CDATA[S 4 ]]> Residual oil 1 53.8 0.00 0.25 0.65 0.94 0.37

[0061] Step 3, obtain the geological factors that affect the mobility of interlayer shale oil in the samples selected in step 1, including reservoir rock single layer thickness, reservoir rock porosity, reservoir rock average pore size, shale single layer thickness and shale total organic carbon content, and then determine the relationship between a single geological factor and the amount of movable oil. The results are as follows: Figure 3-7 As shown;

[0062] Step 4: According to the movable oil volume obtained in step 2 and the geological factors obtained in step 3, a quantitative evaluation model for the mobility of interlayer shale oil based on multivariate regression was established; SPSS software was used to perform multivariate regression analysis on 36 groups of data in the study area, and the variables Hsand, Por, Ra, Hshale, and TOC were selected into the independent variable box, and the movable oil volume (S 1 +S 21 ) is selected into the dependent variable box, and the constants and coefficients of the respective variables in the multiple regression model are analyzed. Finally, the quantitative evaluation model of interlayer shale oil mobility based on multiple regression is obtained: Movable oil volume (S 1 +S 21 )=-0.510-0.130*H sand -0.039*Por+5.640*R a +0.126*H shale +0.162*TOC

[0063] Evaluation results such as Figure 8 As shown in the figure, the measured results are consistent with the movable oil volume (S) obtained by evaluating the interlayer shale oil mobility quantitative evaluation model based on multiple regression of the present invention. 1 +S 21 ) are significantly correlated, R 2 It is 0.8419, indicating that the quantitative evaluation model of interlayer shale oil mobility based on multivariate regression has good applicability.

[0064] Example 4

[0065] The reliability of the quantitative evaluation model for interlayer shale oil mobility based on multivariate regression obtained in Example 3 was tested using 18 new data from the J region. The relevant data are shown in Table 2:

[0066] Table 2 Evaluation results of the quantitative evaluation model for interlayer shale oil mobility based on multivariate regression in the J region

[0067]

[0068]

[0069] According to the data in Table 2 and Fig. 9 Correlation between the evaluation results and the measured movable oil amount R 2 It is 0.8094.

Claims

1. A method for rapidly evaluating the mobility of interlayer shale oil, characterized in that: Follow the steps below to implement it: Step 1, selecting different types of interlayer shale oil reservoir rock samples; Step 2, analyzing the oil and gas components of the sample selected in step 1 and calculating the movable oil volume; Step 3, obtaining geological factors affecting the mobility of interlayer shale oil from the samples selected in step 1; Step 4, establishing a quantitative evaluation model for the mobility of interlayer shale oil based on multivariate regression; Step 5, substitute the geological factors affecting the mobility of interlayer shale oil of the target to be evaluated into the model of step 4 to obtain the movable oil volume of interlayer shale oil of the target to be evaluated.

2. The method for rapidly evaluating the mobility of interlayer shale oil according to claim 1, characterized in that: In step 2, the analysis of oil and gas components is carried out by pyrolysis experiment. The specific process is as follows: the natural gas S0 is tested at a constant temperature of 90°C for 2 minutes, the gasoline content S1 is tested at a constant temperature of 200°C for 1 minute, and then the temperature is increased to 350°C at a heating rate of 50°C / min and kept at a constant temperature for 1 minute to test the kerosene and diesel content S 21 Then, the temperature was raised to 450℃ at a rate of 50℃ / min and kept constant for 1min to test the wax content S 22 Then the temperature was raised to 600℃ at a rate of 50℃ / min and kept at this temperature for 1min to test the content of heavy hydrocarbons and colloidal asphaltene. 23 .

3. The method for rapidly evaluating the mobility of interlayer shale oil according to claim 1, characterized in that: In step 2, movable oil volume = S1 + S 21 .

4. The method for rapidly evaluating the mobility of interlayer shale oil according to claim 3, characterized in that: In step 3, the geological factors that affect the mobility of interlayer shale oil include reservoir rock single layer thickness, reservoir rock porosity, reservoir rock average pore size, shale single layer thickness and shale total organic carbon content.

5. The method for rapidly evaluating the mobility of interlayer shale oil according to claim 4, characterized in that: The single-layer thickness of the reservoir rock is determined by logging data and logging lithology interpretation; the porosity of the reservoir rock is directly obtained based on a pore-permeability test experiment; the average pore size of the reservoir rock is obtained by a high-pressure mercury injection experiment; the single-layer thickness of the shale is determined by logging data and logging lithology interpretation; and the total organic carbon content is obtained by experimental analysis.

6. The method for rapidly evaluating the mobility of interlayer shale oil according to claim 4, characterized in that: The quantitative evaluation model of interlayer shale oil mobility based on multivariate regression is: Movable oil volume = b0 + b1 * H sand +b2*Por+b3*R a +b4*H shale +b5*TOC; In the formula, H sand is the single-layer thickness of reservoir rock; Por is the porosity of reservoir rock; R a is the average pore size of reservoir rock; H shale is the thickness of a single shale layer; TOC is the total organic carbon content of shale; b0, b1, b2, b3, b4, and b5 are model parameters obtained by multiple regression.

7. The method for rapidly evaluating the mobility of interlayer shale oil according to claim 6, characterized in that: SPSS software was used to perform multiple regression analysis and the H obtained in step 3 was sand , Por, R a , H shale , select the TOC variable into the independent variable box, and select the movable oil amount obtained in step 2 into the dependent variable box to obtain b0, b1, b2, b3, b4, and b5.

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