Method for quantitatively evaluating hydrocarbon supply capacity of high and over-mature hydrocarbon source rocks

Abstract

The invention relates to a method for quantitatively evaluating the hydrocarbon supply capacity of high and over-mature hydrocarbon source rocks. The method comprises the following steps: S1, determining the oil gas charging time te of a structural trap; s2, calculating the hydrocarbon generation intensity Ge of the high and over-mature hydrocarbon source rocks in the charging period; s3, determining the hydrocarbon supply convergence area S of the high and over-mature hydrocarbon source rocks; and S4, calculating the hydrocarbon supply potential Qe of the high and over-mature hydrocarbon source rocks, wherein Qe = Ge * S. According to the novel method for evaluating the hydrocarbon expulsion amount of the marine high and over-mature hydrocarbon source rocks, the key reservoir forming period of the trap is determined through fluid inclusion research, and the lateral conduction capability of providing conduction conditions for the structural trap by the fault is quantitatively represented through a seismic structure interpretation method; the hydrocarbon generation strength evolution of the highly over-mature hydrocarbon source rock and the trap structure evolution are dynamically combined, and the problem that the hydrocarbon supply capacity of the hydrocarbon source rock cannot be scientifically predicted by a conventional oil and gas resource potential evaluation method under the condition that curtain type oil and gas charging is carried out on the structural trap through lateral conduction of a fault is solved.

Description

Technical Field

[0001] The present invention belongs to a data processing method for solving equations, and in particular relates to a method for quantitatively evaluating the hydrocarbon supply capacity of highly mature and over-mature source rocks. Background Art

[0002] For source rocks in the highly mature to overmature evolutionary stages, the hydrocarbons generated often escape, resulting in the source rock's hydrocarbon supply capacity being far less than its total hydrocarbon generation intensity. Quantitatively calculating the hydrocarbon supply capacity of source rocks during the critical period of structural trap formation has become a key research topic in oil and gas resource assessment.

[0003] Existing methods for evaluating the hydrocarbon supply capacity of source rocks can be used to assess their hydrocarbon supply capacity by calculating their hydrocarbon generation potential. However, for some traps, oil and gas charging occurs after the source rock and reservoir form a lateral docking relationship. Existing methods for evaluating the hydrocarbon supply capacity of source rocks cannot integrate the formation of the source-reservoir docking relationship with the evolution of highly mature and over-mature source rocks. To meet the practical needs of natural gas reservoir resource assessment, new quantitative assessment methods for the hydrocarbon supply capacity of highly mature and over-mature source rocks are needed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art and provide a method for quantitatively evaluating the hydrocarbon supply capacity of highly mature and over-mature source rocks. This method takes into account the loss of some of the oil and gas generated by highly mature and over-mature source rocks, avoids the problem of errors in the prior art when using total hydrocarbon generation intensity to calculate the gas supply potential of source rocks, combines the evolution of the hydrocarbon generation intensity of source rocks with the formation of a source-reservoir docking relationship, and has good practicality for evaluating the hydrocarbon supply capacity of source rocks that are laterally transported through faults.

[0005] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0006] A method for quantitatively evaluating the hydrocarbon supply capacity of highly mature and over-mature source rocks is provided, comprising the following steps:

[0007] S1. Determine the oil and gas filling time of the structural trap: Use fluid inclusion experiments to measure the homogenized temperature of fluid inclusions associated with hydrocarbon inclusions in the reservoir section of typical well cores. After statistical analysis, obtain a homogenized temperature distribution histogram of the fluid inclusions associated with the hydrocarbon inclusions. Based on the homogenized temperature distribution histogram of the fluid inclusions associated with the hydrocarbon inclusions, determine the paleo-geotemperature when the fluid inclusions associated with the hydrocarbon inclusions were captured. Project the paleo-geotemperature value of the first captured hydrocarbon inclusion onto a burial history map and compare it with the thermal evolution history to obtain the geological period corresponding to the paleo-geotemperature when the hydrocarbon inclusions were captured, which is the oil and gas filling time t of the structural trap. e ;

[0008] S2. Calculation of hydrocarbon generation intensity during the charging period of highly mature and over-mature source rocks: Using basin simulation software, simulate the evolution of source rocks in paleo-geothermal models based on source rock type. When the vitrinite reflectance Ro of the source rock is greater than 1.0%, the source rock begins to generate large amounts of hydrocarbons, i.e., enters the mature evolution stage. The time to when the source rock enters the mature evolution stage (large amounts of hydrocarbon generation) is obtained based on the thermal evolution simulation results of the vitrinite reflectance Ro of the source rock. Assuming that the oil and gas generated by the source rock from the mature evolution stage to the present (this assumption is reasonable because the frequency of tectonic movement on a macroscopic geological time scale can be considered uniform) is uniformly dissipated due to the influence of tectonic movement, the hydrocarbon generation intensity Ge of the highly mature and over-mature source rocks during the charging period is calculated using the linear interpolation method.

[0009] S3. Determining the hydrocarbon supply convergence area of ​​highly mature and over-mature source rocks: Obtaining a top structural map of the trapped reservoir, a source rock section variance attribute map, and a source rock bottom chaotic attribute plan map through seismic geological interpretation; distinguishing the source rock section (a source rock section is formed by a fault connecting the source rock and the reservoir in the structural trap, which cuts through the source rock) and the top structural morphology of the reservoir based on the top structural map of the trapped reservoir and the source rock section variance attribute map; defining the area where the source rock section overlaps with the top surface of the reservoir as an area where the trap has a source-reservoir configuration; and identifying areas where structural fractures are relatively developed based on the source rock bottom chaotic attribute plan map. Defining the area where fractures are developed and the trap has a source-reservoir configuration as the hydrocarbon supply convergence area S of highly mature and over-mature source rocks;

[0010] S4. Calculate the hydrocarbon supply potential of the highly mature and over-mature source rocks: Based on the hydrocarbon generation intensity Ge of the highly mature and over-mature source rocks during the charging period obtained in step S2 and the hydrocarbon supply convergence area S of the highly mature and over-mature source rocks obtained in step S3, obtain the hydrocarbon supply potential Qe of the highly mature and over-mature source rocks, where Qe=Ge×S.

[0011] According to the above scheme, the specific steps of step S1 are as follows:

[0012] Step 1: Use fluid inclusion testing equipment to heat the processed inclusion slices and continuously observe the fluid inclusions until the two-phase connection disappears. Record the temperature when the fluid inclusions reach a homogeneous phase. After statistical analysis, obtain a homogeneous temperature distribution histogram of the fluid inclusions associated with the hydrocarbon-bearing inclusions. The peak value in the histogram is taken as the paleotemperature when the fluid inclusions associated with the hydrocarbon-bearing inclusions were captured.

[0013] The second step: collect the vitrinite reflectance Ro data of typical wells and restore the burial history of the formation with drilling, seismic and other data. Perform Ro forward modeling through basin simulation software to comprehensively obtain the paleo-geothermal model of geological age changes. Compare the simulated vitrinite reflectance values ​​with the measured values ​​to correct the paleo-geothermal model until the Ro simulation value curve overlaps with the measured value curve. Then, a reasonable thermal evolution history map is obtained. The paleo-geothermal value obtained in the first step is projected onto the burial history map and compared with the thermal evolution history to obtain the geological period t corresponding to the paleo-geothermal temperature when the hydrocarbon inclusions were captured. e .

[0014] According to the above scheme, in step S2, the formula used in the linear interpolation method is:

[0015]

[0016] Wherein, Go is the hydrocarbon generation intensity of the source rock during the peak period of hydrocarbon generation, which can be determined by the method of calculating the hydrocarbon expulsion rate and hydrocarbon expulsion amount of highly overmature source rocks in the patent "Evaluation Method for Hydrocarbon Expulsion of Marine Highly Overmature Source Rocks" by Wang Wenyang et al.; Gn is the current hydrocarbon generation intensity of the source rock, and Gn=I×ρ×A×H, wherein I is the current gas content of the source rock, ρ is the average density of the source rock, A is the distribution area of ​​the source rock, and H is the average thickness of the source rock (specific data can be obtained through core, logging and seismic data during the exploration process).

[0017] In step S3, a structural map of the top surface of the trapped reservoir, a variance attribute map of the source rock section, and a chaotic attribute plane map of the bottom surface of the source rock are obtained through seismic geological interpretation. The specific steps are: using seismic interpretation software, first, the strata are distinguished by interpretation and tracking of the seismic reflection interface, then the structural surface is generated by numerical simulation to obtain the structural map of the top surface of the trapped reservoir, variance attributes are generated along the section slice of the source rock to generate the variance attribute map of the source rock section, and finally, a chaotic three-dimensional seismic attribute body is generated, and the chaotic attribute plane map of the bottom surface of the source rock is obtained along the section slice.

[0018] The beneficial effects of the present invention are as follows: the present invention provides a new method for evaluating the hydrocarbon expulsion volume of marine high- and over-mature source rocks, determines the key accumulation period of the trap through fluid inclusion research, quantifies the lateral conductivity of the fault that provides the conductivity conditions for the structural trap through seismic structural interpretation methods, combines the hydrocarbon generation intensity evolution of the high- and over-mature source rocks with the dynamic structural evolution of the trap, and solves the problem that conventional oil and gas resource potential assessment methods cannot scientifically predict the hydrocarbon supply capacity of the source rock when the structural trap undergoes episodic oil and gas charging through lateral conductivity of faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a diagram of the burial history and thermal evolution history of the formation of Well A in Example 1;

[0020] Figure 2 This is a histogram of uniform temperature distribution of fluid inclusions in Well A in Example 1;

[0021] Figure 3 This is a diagram of shale hydrocarbon supply intensity during the main trap filling period in Example 1;

[0022] Figure 4 The superposition diagram of the trap top surface structure map and the stratigraphic section variance attribute in Example 1;

[0023] Figure 5 This is a plan view of the chaotic properties of the bottom surface of the stratum in Example 1. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings.

[0025] Example 1

[0026] The XX region is a nearly diamond-shaped fold belt that has undergone multi-cycle tectonic transformation. Faults have developed that connect source rocks in the underlying strata with reservoirs in the underlying strata. These faults connect the source and reservoir configuration, forming an "upper generation, lower reservoir" accumulation model. The source rock strata studied in this example have reached a high-to-overmature evolutionary stage, are 100-300 meters thick, and are widely distributed across the region.

[0027] This embodiment provides a method for quantitatively evaluating the hydrocarbon supply capacity of highly mature and over-mature source rocks, comprising the following steps:

[0028] S1. Determine the oil and gas filling time of the structural trap:

[0029] Step 1: Using fluid inclusion testing equipment, thin inclusion sections prepared from core reservoir sections of typical wells were heated. Fluid inclusions associated with hydrocarbon inclusions were continuously observed under a microscope until the two-phase junction of the inclusions disappeared. The temperature at which the fluid inclusions reached a homogeneous phase was recorded. The data was then statistically analyzed to obtain a homogeneous temperature distribution histogram of the fluid inclusions associated with the hydrocarbon inclusions. The peak value in the histogram was taken as the paleotemperature at which the fluid inclusions associated with the hydrocarbon inclusions were captured. The main peak temperature of the first phase of the average inclusion temperature was determined to be 65°C (midway between 60°C and 70°C), indicating that the reservoir underwent a phase of fluid charging at this paleotemperature.

[0030] The second step: collect the vitrinite reflectance Ro data of typical wells and restore the burial history of the formation with drilling, seismic and other data, perform Ro forward modeling through basin simulation software, and comprehensively obtain the paleo-geothermal model of geological age changes. Compare the simulated vitrinite reflectance values ​​with the measured values ​​to correct the paleo-geothermal model until the Ro simulation value curve and the measured value curve overlap, and then draw a reasonable thermal evolution history map. Combined with the burial history map of the formation of well A in the eastern Sichuan area, on this map, the 65℃ isotherm corresponds to the geological period of 500Ma. At this time, the source rock is not mature, indicating that this period is not the time of oil and gas filling. The main peak temperature of the homogenization temperature of the second period inclusion is 190℃ (take the middle value between 180℃ and 200℃). Combined with the burial history and thermal evolution history map of the formation A in the study area, the reservoir corresponds to the geological period of about 80Ma at the 190℃ isotherm (see the attached map for details). Figure 2 ), which is the oil and gas filling time of the structural trap t e ;

[0031] S2. Calculation of hydrocarbon generation intensity of high-mature and over-mature source rocks during the filling period: basin simulation software was used to simulate the evolution of source rocks in the paleo-geothermal model according to the source rock type. When the vitrinite reflectance Ro of the source rock was greater than 1.0%, the source rock began to generate a large amount of hydrocarbons, i.e., entered the mature evolution stage. Based on the results of thermal evolution simulation of the vitrinite reflectance Ro of the source rock, the time to when the source rock entered the mature evolution stage (large amount of hydrocarbon generation) was obtained. The time to when the source rock began to generate a large amount of hydrocarbons was determined to be approximately 230 Ma (see Appendix for details). Figure 1 ), assuming that the oil and gas generated by the source rock from the peak hydrocarbon generation period to the present is uniformly dissipated due to tectonic movement, the hydrocarbon generation intensity Ge of the high and over-mature source rock during the filling period is calculated based on the linear interpolation method between the present time and the hydrocarbon generation intensity. In this example, the hydrocarbon generation intensity of the source rock during the peak hydrocarbon generation period is about 50×10 8 m 3 / km 2 , that is, G o =50×10 8 m 3 / km 2 ;

[0032] The formula of the linear interpolation method is:

[0033]

[0034] Among them G o is the hydrocarbon generation intensity of the source rock during the peak period; t o G is the time from the peak of hydrocarbon generation of source rock to the present; n It is the hydrocarbon generation intensity of the current source rock.

[0035] The G n=I×ρ×A×H, where I is the gas content of the source rock; ρ is the average density of the source rock; A is the distribution area of ​​the source rock; and H is the average thickness of the source rock.

[0036] The current hydrocarbon generation intensity G of the source rocks in the study area is obtained by calculation. n 12×10 8 m 3 / km 2 The hydrocarbon generation intensity G of the source rock in the studied trap during the main filling period is e 25×10 8 m 3 / km 2 (See attached Figure 3 ).

[0037] S3. Determine the hydrocarbon supply convergence area of ​​high- and over-mature source rocks. In this embodiment, seismic interpretation software is used to interpret and track seismic reflection interfaces to distinguish strata, and then a structural surface is generated through numerical simulation to obtain a structural map of the reservoir top surface. Variance attributes are generated along the source rock section slice to generate a source rock section variance attribute map. Finally, a chaotic three-dimensional seismic attribute volume is generated, and a chaotic attribute plane map of the source rock stratum bottom surface is obtained along the structural surface slice. Based on the trapped reservoir top surface structural map and the source rock section variance attribute map, the structural morphology of the source rock section and the reservoir top surface are distinguished, and the area where the source rock section and the reservoir top surface overlap is delineated as the trapped area with source-reservoir configuration (e.g., Figure 4 Based on the chaotic attribute plane map of the source rock bottom, the area with relatively developed structural fractures is identified, and the area with developed fractures and trapped source-reservoir configuration is defined as the hydrocarbon supply convergence area S of high and over-mature source rock, as shown in Figure 5 As shown, the calculated S is 12km 2 .

[0038] S4. Calculate the hydrocarbon supply potential of the highly mature and over-mature source rocks. In this embodiment, the hydrocarbon supply convergence area S of the highly mature and over-mature source rocks and the hydrocarbon generation intensity G of the highly mature and over-mature source rocks during the filling period are calculated. e , obtain the hydrocarbon supply potential Q of high and over-mature source rocks in the main filling period e =G e ×S.

[0039] The hydrocarbon supply potential Q of the source rock trapped in the study area during the main filling period is calculated through step S4. e 300×10 8 m 3 Well A1 produces 25×10 4 m 3 As of now, the total output is 6753×10 4 m 3 , considering the actual development situation and oil and gas exploration technology issues, the estimated hydrocarbon supply potential results are relatively reasonable.

[0040] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for quantitatively evaluating the hydrocarbon supply capacity of highly mature and over-mature source rocks, characterized in that: The following steps are involved: S1. Determine the oil and gas filling time of the structural trap: Use fluid inclusion experiments to measure the homogenized temperature of fluid inclusions associated with hydrocarbon inclusions in the reservoir section of typical well cores. After statistical analysis, obtain a homogenized temperature distribution histogram of the fluid inclusions associated with the hydrocarbon inclusions. Based on the homogenized temperature distribution histogram of the fluid inclusions associated with the hydrocarbon inclusions, determine the paleo-geotemperature when the fluid inclusions associated with the hydrocarbon inclusions were captured. Project the paleo-geotemperature value of the first captured hydrocarbon inclusion onto a burial history map and compare it with the thermal evolution history to obtain the geological period corresponding to the paleo-geotemperature when the hydrocarbon inclusions were captured, which is the oil and gas filling time t of the structural trap. e ; S2. Calculation of hydrocarbon generation intensity during the charging period of highly mature and over-mature source rocks: Using basin simulation software, simulate the evolution of source rocks in paleo-geothermal models based on source rock types. When the vitrinite reflectance Ro of the source rocks is greater than 1.0%, the source rocks begin to generate large amounts of hydrocarbons, i.e., enter the mature evolution stage. The time to when the source rocks enter the mature evolution stage is obtained based on the thermal evolution simulation results of the vitrinite reflectance Ro of the source rocks. Assuming that the oil and gas generated by the source rocks from the mature evolution stage to the present have been uniformly dissipated due to tectonic movement, the hydrocarbon generation intensity Ge of highly mature and over-mature source rocks during the charging period is calculated using the linear interpolation method. S3. Determining the hydrocarbon supply convergence area of ​​highly mature and over-mature source rocks: Obtaining a top structural map of the trapped reservoir, a source rock section variance attribute map, and a source rock bottom chaotic attribute plane map through seismic geological interpretation; distinguishing the structural morphology of the source rock section and the reservoir top based on the top structural map of the trapped reservoir and the source rock section variance attribute map; defining the area where the source rock section overlaps with the reservoir top as an area where the trap has a source-reservoir configuration; and distinguishing areas where structural fractures are relatively developed based on the source rock bottom chaotic attribute plane map; and defining the area where fractures are developed and the trap has a source-reservoir configuration as the hydrocarbon supply convergence area S of highly mature and over-mature source rocks; S4. Calculate the hydrocarbon supply potential of the highly mature and over-mature source rocks: Based on the hydrocarbon generation intensity Ge of the highly mature and over-mature source rocks during the charging period obtained in step S2 and the hydrocarbon supply convergence area S of the highly mature and over-mature source rocks obtained in step S3, obtain the hydrocarbon supply potential Qe of the highly mature and over-mature source rocks, where Qe=Ge×S.

2. The method for quantitatively evaluating the hydrocarbon supply capacity of highly mature and over-mature source rocks according to claim 1, characterized in that: The specific steps of step S1 are as follows: Step 1: Use fluid inclusion testing equipment to heat the processed inclusion slices and continuously observe the fluid inclusions until the two-phase connection disappears. Record the temperature when the fluid inclusions reach a homogeneous phase. After statistical analysis, obtain a homogeneous temperature distribution histogram of the fluid inclusions associated with the hydrocarbon-bearing inclusions. The peak value in the histogram is taken as the paleotemperature when the fluid inclusions associated with the hydrocarbon-bearing inclusions were captured. The second step: collect the vitrinite reflectance Ro data of typical wells and restore the burial history of the formation with drilling, seismic and other data. Perform Ro forward modeling through basin simulation software to comprehensively obtain the paleo-geothermal model of geological age changes. Compare the simulated vitrinite reflectance values ​​with the measured values ​​to correct the paleo-geothermal model until the Ro simulation value curve overlaps with the measured value curve. Then, a reasonable thermal evolution history map is obtained. The paleo-geothermal value obtained in the first step is projected onto the burial history map and compared with the thermal evolution history to obtain the geological period t corresponding to the paleo-geothermal temperature when the hydrocarbon inclusions were captured. e .

3. The method for quantitatively evaluating the hydrocarbon supply capacity of highly mature and over-mature source rocks according to claim 1, characterized in that: In step S2, the formula used in the linear interpolation method is Wherein, Go is the hydrocarbon generation intensity of the source rock during the peak period of hydrocarbon generation, Gn is the current hydrocarbon generation intensity of the source rock, and Gn=I×ρ×A×H, wherein I is the current gas content of the source rock, ρ is the average density of the source rock, A is the distribution area of ​​the source rock, and H is the average thickness of the source rock.

4. The method for quantitatively evaluating the hydrocarbon supply capacity of highly mature and over-mature source rocks according to claim 1, characterized in that: In step S3, a structural map of the top surface of the trapped reservoir, a variance attribute map of the source rock section, and a chaotic attribute plane map of the bottom surface of the source rock are obtained through seismic geological interpretation. The specific steps are: using seismic interpretation software, first, the strata are distinguished by interpretation and tracking of the seismic reflection interface, then the structural surface is generated by numerical simulation to obtain the structural map of the top surface of the trapped reservoir, variance attributes are generated along the section slice of the source rock to generate the variance attribute map of the source rock section, and finally, a chaotic three-dimensional seismic attribute body is generated, and the chaotic attribute plane map of the bottom surface of the source rock is obtained along the section slice.

Images