Hydrocarbon generation and expulsion simulation experiment method and device

Abstract

The invention provides a hydrocarbon generation and expulsion simulation experiment method and device, and the method comprises the steps: building a geological concept model according to a mixed rock sample of a target layer; geological parameters of the depth corresponding to the current Ro of the mixed rock of the target layer are determined, and simulation experiment conditions are determined according to the geological parameters; preparing a mixed rock experiment sample; loading a mixed rock experiment sample into a sample chamber of a hydrocarbon generation and expulsion simulation experiment device, and carrying out hydrocarbon generation and expulsion simulation on the mixed rock according to the simulation experiment conditions; and collecting products of the hydrocarbon generation and expulsion simulation, and carrying out hydrocarbon generation and expulsion quantitative evaluation. According to the method, different geological concept models are established according to the typical lithology and lamina combination of the target stratum, the hydrocarbon generation and expulsion simulation experiment under the actual stratum temperature and pressure condition is carried out, the hydrocarbon expulsion efficiency and the hydrocarbon generation and expulsion amount of different types of mixed rock are evaluated, and parameters and basis are provided for evaluation of oil and gas resources of an oil and gas containing basin for developing the mixed rock.

Description

Technical Field

[0001] This application relates to the technical field of oil and gas resource evaluation, and particularly to a method and device for simulating hydrocarbon generation and expulsion experiments. Background Art

[0002] Mixed sedimentary rocks are rocks formed by the mixed deposition of terrigenous clastic and carbonate components, and can be widely developed in marine, transitional marine and continental environments. Source rocks formed under the background of continental mixed sedimentation are widely distributed and are an important type of source rock, such as the upper member of the Lower Ganchaigou Formation in the Yingxi area of the Qaidam Basin and the Permian Lucaogou Formation in the Junggar Basin.

[0003] The formation of mixed sedimentary rocks is comprehensively affected by factors such as tectonic movement, climate, provenance, and lake level changes. Different types of source rocks formed under the background of mixed sedimentation have strong heterogeneity in terms of lithological composition, mineral content, and organic matter components. Strong heterogeneity is a common feature of mixed sedimentary rock series in Chinese continental basins. For example, the mixed sedimentary rocks in the Permian Lucaogou Formation in the Jimusaer Sag of the Junggar Basin are mainly composed of dark mudstones, siltstones, carbonate rocks and their transitional lithologies, with frequent vertical interbedding; the mixed sedimentary rocks formed in the northwestern region of the Qaidam Basin are mainly composed of a rhythmic combination of carbonate rocks, mudstones and siltstones; the fine-grained mixed sedimentary rocks in the Kongdian Formation in the Cangdong Sag of the Bohai Bay Basin have extremely rapid vertical evolution of different minerals, and are combined in various ways such as interbedding, intercalation or gradual change.

[0004] The heterogeneity of mixed sedimentary rocks in terms of organic matter, mineral composition, lithological combination, etc. cannot be ignored in the impact on hydrocarbon generation and expulsion of this type of source rock. On the one hand, the hydrocarbon generation capabilities of different lithologies in mixed sedimentary rocks are significantly different. For example, among the samples of mudstone, dolomite and siltstone in the mixed sedimentary rocks of the Lucaogou Formation in the Jimusaer Sag of the Junggar Basin, the hydrocarbon generation capabilities decrease in turn. On the other hand, the difference in lithological combination also has a great impact on the hydrocarbon expulsion of mixed sedimentary rocks. During the process of hydrocarbon generation and expulsion of source rocks, the generated hydrocarbons must first satisfy the saturated adsorption of the source rock itself. Only when the hydrocarbon generation amount of the source rock exceeds its own adsorption capacity can hydrocarbon expulsion occur. Different mineral contents have different adsorption capacities for soluble organic matter. For example, macromolecules of soluble organic matter containing a large number of polar groups are easily adsorbed on the surface of clay mineral crystals, while the adsorption capacity of carbonate minerals for soluble organic matter is relatively weak. Therefore, the mineral heterogeneity caused by lithological combination differences will affect the hydrocarbon generation and expulsion process of mixed sedimentary rock series. However, the current research on hydrocarbon generation and expulsion of mixed sedimentary rock series is still very weak, and there are few reports on simulation experiments for hydrocarbon generation and expulsion of mixed sedimentary rocks.

[0005] Previous hydrocarbon generation and expulsion simulation experiments on mud shale were mostly carried out on single lithology source rocks, and it was impossible to quantitatively characterize the differences in hydrocarbon generation and expulsion caused by the heterogeneity of mixed rocks. Most of the existing technologies use direct pressure semi-open and semi-closed thermal simulation experiments. By collecting experimental products, the hydrocarbon expulsion efficiency is quantitatively calculated. The heterogeneity of the source rock is not involved in the simulated samples, and it is difficult to effectively characterize the influence of the lithology, minerals and organic matter heterogeneity of mixed rocks on hydrocarbon generation and expulsion. There are also some in the hydrocarbon generation and expulsion simulation experiments, where a sandstone layer is set on the upper part of the source rock, and a simulation experiment is designed for the contact mode between sandstone and mudstone, but it is not completely applicable to the mixed rock series. In the hydrocarbon generation and expulsion experiments of mixed rocks, it is necessary to establish a targeted geological conceptual model according to different types of lithology and mineral combinations in mixed rocks, and then determine the hydrocarbon generation and expulsion amounts of different types of mixed rocks, so as to reflect the hydrocarbon generation and expulsion characteristics of the source rocks in the mixed layer series. Summary of the Invention

[0006] In view of this, the present application provides a method and device for hydrocarbon generation and expulsion simulation experiments, so as to solve the technical problems in the existing technology that the hydrocarbon generation and expulsion simulation experiments do not consider the influence of the lithology, minerals and organic matter heterogeneity of mixed rocks on hydrocarbon generation and expulsion, and cannot reflect the hydrocarbon generation and expulsion characteristics of the source rocks in the mixed layer series.

[0007] In the first aspect, an embodiment of the present application provides a method for hydrocarbon generation and expulsion simulation experiments, and the method includes:

[0008] According to the mixed rock samples of the target layer, establish a geological conceptual model, and the mixed rock samples include source rocks and non-source rocks;

[0009] Determine the geological parameters corresponding to the current R o at the corresponding depth of the mixed rocks of the target layer, and determine the simulation experiment conditions according to the geological parameters;

[0010] Prepare mixed rock experimental samples according to the geological conceptual model;

[0011] Load the mixed rock experimental samples into the sample chamber of the hydrocarbon generation and expulsion simulation experimental device, and carry out the hydrocarbon generation and expulsion simulation of the mixed rocks according to the simulation experiment conditions;

[0012] Collect the products of the hydrocarbon generation and expulsion simulation, and conduct a quantitative evaluation of hydrocarbon generation and expulsion.

[0013] Further, according to the mixed rock samples of the target layer, establishing a geological conceptual model, and the mixed rock samples include source rocks and non-source rocks, includes:

[0014] Obtain various mixed rock samples of the target layer;

[0015] Conduct organic geochemistry and mineral content analysis on the mixed rock samples to determine the lithology and lamination combination characteristics of the mixed rock samples;

[0016] Based on the lithology and lamination combination characteristics of the mixed sedimentary rock samples, different geological conceptual models are established.

[0017] Furthermore, determining the lithology of the source rock includes:

[0018] Determining the basic geochemical parameters of the mixed sedimentary rock samples, where the basic geochemical parameters include total organic carbon content TOC, hydrogen index HI, and pyrolysis peak temperature T max ;

[0019] According to the total organic carbon content TOC, the mixed sedimentary rock samples are divided into rich organic matter mixed sedimentary rocks, high organic matter mixed sedimentary rocks, medium organic matter mixed sedimentary rocks, and poor organic matter mixed sedimentary rocks;

[0020] According to the hydrogen index HI and the pyrolysis peak temperature T max , determine the organic matter type of the source rock in the mixed sedimentary rock samples, and divide the source rock into type I source rock, type II source rock, and type III source rock according to the organic matter type.

[0021] Furthermore, the geological parameters include actual formation fluid pressure and thermal maturity parameters; the simulation experiment conditions include experimental pressure, experimental temperature, and constant temperature time.

[0022] Furthermore, loading the mixed sedimentary rock experimental samples into the sample chamber of the hydrocarbon generation and expulsion simulation experimental device, and performing the hydrocarbon generation and expulsion simulation of the mixed sedimentary rock according to the simulation experiment conditions, including:

[0023] Load the mixed sedimentary rock experimental samples into the sample chamber of the hydrocarbon generation and expulsion simulation experimental device, install the sample chamber in the reaction kettle, conduct an airtightness test, and after the airtightness is qualified, evacuate the sample chamber;

[0024] Prepare the experimental formation water, inject the experimental formation water into the sample chamber, make the experimental formation water fill the pore space of the mixed sedimentary rock experimental samples, and keep the initial formation fluid pressure of the sample chamber at a certain value;

[0025] Apply a set static rock pressure to the mixed sedimentary rock experimental samples, raise the temperature to the set experimental temperature at the set heating rate, and maintain the set constant temperature time to conduct the hydrocarbon generation and expulsion simulation;

[0026] When the formation fluid pressure in the sample chamber reaches the hydrocarbon expulsion pressure threshold, the hydrocarbon expulsion valve automatically opens and discharges hydrocarbons. When the formation fluid pressure in the sample chamber returns to the actual formation fluid pressure, the hydrocarbon expulsion valve automatically closes, and the above hydrocarbon expulsion process is repeated.

[0027] Furthermore, the products of the hydrocarbon generation and expulsion simulation include:

[0028] Expelled oil, where the expelled oil is the oil expelled from the mixed sedimentary rock series;

[0029] Charging oil, which is the oil injected into adjacent laminations after the hydrocarbon source rock laminations satisfy their own adsorption and reach saturation.

[0030] Retained oil, which is the oil that has not undergone effective hydrocarbon expulsion and still remains in the pore space of the hydrocarbon source rock laminations.

[0031] Furthermore, collecting the products of the hydrocarbon generation and expulsion simulation and conducting quantitative evaluation of hydrocarbon generation and expulsion includes calculating the hydrocarbon expulsion efficiency E based on the products of the hydrocarbon generation and expulsion simulation. The calculation formula for the hydrocarbon expulsion efficiency E is:

[0032]

[0033] where X1 is the amount of oil expelled, X2 is the amount of charging oil, and X3 is the amount of retained oil.

[0034] Furthermore, the calculation methods for the amount of charging oil and the amount of retained oil are as follows: By separately crushing the remaining samples of each lamination collected, weighing them, and then extracting them with dichloromethane respectively, the amount of oil in the non-hydrocarbon source rock laminations in the experimental samples of mixed sedimentary rocks after hydrocarbon generation and expulsion is the amount of charging oil, and the amount of oil in the hydrocarbon source rock laminations is the amount of retained oil.

[0035] In a second aspect, the present application provides a device for the hydrocarbon generation and expulsion simulation experiment method described in the first aspect, characterized in that the device includes:

[0036] A high-temperature and high-pressure hydrocarbon generation reaction system, a two-way hydraulic control system, a hydrocarbon expulsion system, an automatic control and data acquisition system, a product separation and collection system, peripheral auxiliary equipment, and an instrument housing;

[0037] The high-temperature and high-pressure hydrocarbon generation reaction system includes a reaction kettle, a sample chamber, gaskets, an oil pump, a static rock pressure reduction device, a static rock pressure increase device, a static rock pressure monitoring device, a sealing pressure increase device, a sealing pressure reduction device, a formation fluid pressure monitoring device, a pressure compensation pump, a pressure compensator, and an in-kettle pressure compensation device;

[0038] The hydrocarbon expulsion system includes an upper hydrocarbon expulsion device, a lower hydrocarbon expulsion device, a pressure pump, a pressure increasing valve, a pressure reducing valve, and a hydrocarbon expulsion pressure control device;

[0039] The product separation and collection system includes an upper separation and collection system and a lower separation and collection system. The upper separation and collection system includes an upper gas-liquid separation valve, an upper gas-liquid separator, an upper collected gas pressure monitoring device, and an upper gas-liquid collector; the lower separation and collection system includes a lower gas-liquid separator, a lower collected gas pressure monitoring device, and a lower gas-liquid collector;

[0040] One path of the oil pump is sequentially connected to the static rock pressure reducing device, the static rock pressure increasing device and is connected to the upper end of the sample chamber. Another path of the oil pump is connected to the lower end of the sample chamber through the sealing pressure increasing device and the sealing pressure reducing device. The static rock pressure monitoring device is connected between the static rock pressure increasing device and the sample chamber. The upper hydrocarbon discharging device is connected to the upper end of the sample chamber, and the lower hydrocarbon discharging device is connected to the lower end of the sample chamber. The formation fluid pressure monitoring device is connected to the line between the upper hydrocarbon discharging device and the sample chamber. The pressure pump is connected to the line between the upper hydrocarbon discharging device and the upper gas-liquid separation valve through the pressure increasing valve and the pressure reducing valve. The hydrocarbon discharging pressure control device is connected to the line between the pressure increasing valve and the pressure reducing valve and the line between the upper hydrocarbon discharging device and the upper gas-liquid separation valve. The upper separation and collection system is connected to the upper hydrocarbon discharging device, and the lower separation and collection system is connected to the lower hydrocarbon discharging device. One end of the pressure compensating device inside the autoclave is connected between the lower hydrocarbon discharging device and the sample chamber, and the other end of the pressure compensating device inside the autoclave is connected to the pressure compensator, and the pressure compensator is connected to the pressure compensating pump.

[0041] Further, the gasket is a high-porosity and high-permeability gasket made of inorganic materials.

[0042] In view of the characteristics of complex composition, rapid lithology and lithofacies changes, and frequent interbedding in continental mixed sedimentary rock series in this application, according to the actual geological conditions of the study area, considering the differences in hydrocarbon generation and expulsion of different lithologies in the mixed sedimentary series, a geological conceptual model is established based on the typical lithology and laminar combination of the target layer, and hydrocarbon generation and expulsion simulation experiments are carried out under actual formation temperature and pressure conditions to evaluate the hydrocarbon expulsion efficiency and hydrocarbon generation and expulsion volume of different types of mixed rocks, providing parameters and basis for the evaluation of oil and gas resources in oil and gas bearing basins developed with mixed rocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0044] Figure 1 It is a schematic flow chart of a hydrocarbon generation and expulsion simulation experiment method provided by an embodiment of the present application;

[0045] Figure 2 It is a mixed rock lithofacies classification scheme based on rock structure and whole rock mineral composition provided by an embodiment of the present application;

[0046] Figure 3 It is for the embodiment of the present application to judge the organic matter type in mixed rocks according to the hydrogen index HI and the pyrolysis peak temperature T max A chart for judging the organic matter type in mixed rocks;

[0047] Figure 4 This is a pie chart showing the mineral content of the mudstone laminae and carbonate laminae in the mixed rocks of the Permian Lucaogou Formation in the Jimusa'er Sag provided by the embodiments of the present application;

[0048] Figure 5 This is a schematic diagram of the geological conceptual model of the lithology and lamina combination types of some mixed rocks provided by the embodiments of the present application;

[0049] Figure 6 This is a graph showing the relationship between the hydrocarbon generation experiment temperature and the measured R of the mixed rocks of the Permian Lucaogou Formation in the Jimusa'er Sag provided by the embodiments of the present application o Relationship diagram;

[0050] Figure 7 This is a schematic diagram showing the distribution of different laminae of the experimental samples of mixed rocks provided by the embodiments of the present application;

[0051] Figure 8 This is a schematic diagram for the quantitative evaluation of the hydrocarbon generation and expulsion products of mixed rocks provided by the embodiments of the present application;

[0052] Figure 9 This is a structural block diagram of a hydrocarbon generation and expulsion simulation experiment device provided by the embodiments of the present application. Detailed implementation manners

[0053] For a better understanding of the technical solutions of the present application, the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0054] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without any creative work belong to the scope of protection of the present application.

[0055] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0056] It should be understood that the term " / and" used herein is only a description of the associated relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0057] The present application provides a hydrocarbon generation and expulsion simulation experiment method. Refer to Figure 1, which is a schematic flow chart of a method for simulating hydrocarbon generation and expulsion provided by an embodiment of the present application. The method mainly includes the following steps.

[0058] S101: Establish a geological conceptual model based on the mixed sedimentary rock samples of the target layer. The mixed sedimentary rock samples include source rocks and non-source rocks, and specifically include:

[0059] Obtain various types of mixed sedimentary rock samples of the target layer.

[0060] In this embodiment, the Permian Lucaogou Formation in the Jimusar Sag of the Junggar Basin is taken as an example for detailed description. The Lucaogou Formation belongs to typical mixed sedimentary rocks. To establish geological conceptual models of different types of mixed sedimentary rocks, for typical core wells in the study area, continuous high-density sampling is carried out in the depth section where mixed sedimentary rocks are developed in the target layer section to obtain mixed sedimentary rock samples. At the same time, in order to carry out the whole-process simulation experiment of hydrocarbon generation and expulsion, in the target layer section developed in the shallow layer or outcrop of the study area, low-maturity mixed sedimentary rock samples are preferably obtained, and the lithology and laminar structure of the low-maturity mixed sedimentary rock samples are consistent with those of the mixed sedimentary rocks developed in the target layer of the study area.

[0061] Carry out organic geochemistry and mineral content analysis on the mixed sedimentary rock samples to determine the lithology and laminar combination characteristics of the mixed sedimentary rock samples.

[0062] Carry out hand specimen observation and thin section observation on the mixed sedimentary rock samples, depict and classify the lithology combination. Among them, the lithology classification adopts the "four-component and three-end-member" classification scheme. The "four components" refer to the organic matter component, terrigenous clastic component, carbonate component, and volcanic clastic component; the "three end-members" include the terrigenous clastic content, carbonate content, and volcanic clastic content. The mixed sedimentary rock lithofacies classification scheme based on rock structure and whole-rock mineral composition obtained by the "four-component and three-end-member" classification scheme is as Figure 2As shown in the figure, where I is carbonate rock, II1 is tuffaceous carbonate rock, II2 is (silty) / argillaceous carbonate rock, III1 is tuffaceous carbonate rock, III2 is (silty) / argillaceous carbonate rock, IV is tuff, V1 is (silty) / argillaceous sedimentary tuff, V2 is calcareous / dolomitic sedimentary tuff, VI1 is (silty) / argillaceous sedimentary tuff, VI2 is calcareous / dolomitic sedimentary tuff, VII is (silty) sandstone / mudstone, VIII1 is tuffaceous (silty) sandstone / mudstone, VIII2 is dolomitic / calcareous (silty) sandstone / mudstone, IX1 is tuffaceous (silty) sandstone / mudstone, IX2 is calcareous / dolomitic (silty) sandstone / mudstone, X1 is volcanic clastic positive mixed sedimentary rock, X2 is terrigenous clastic positive mixed sedimentary rock, and X3 is carbonate positive mixed sedimentary rock. The results show that the mixed sedimentary rocks in the Permian Lucaogou Formation in the Jimusa'er Sag have the ternary mixed sedimentary characteristics of volcanic rocks, clastic rocks, and carbonate rocks, and develop various types of laminar combinations. In this embodiment, the laminar combination of organic-rich mudstone and organic-poor carbonate rock is taken as an example to illustrate the present application in detail.

[0063] Determine the basic geochemical parameters of the mixed sedimentary rock samples through experiments such as Rock-Eval pyrolysis. The basic geochemical parameters include total organic carbon content TOC, free hydrocarbon content S1, pyrolysis hydrocarbon content S2, pyrolysis peak temperature T max , hydrogen index HI, production index PI, and hydrocarbon index [100×S1] / TOC;

[0064] Classify the mixed sedimentary rock samples according to the total organic carbon content TOC: when TOC≥4.0%, it is organic-rich mixed sedimentary rock; when 2.0%≤TOC<4.0%, it is high-organic-matter mixed sedimentary rock; when 1.0%≤TOC<2.0%, it is medium-organic-matter mixed sedimentary rock; when TOC<1.0%, it is organic-poor mixed sedimentary rock;

[0065] According to the hydrogen index HI and the pyrolysis peak temperature T max , determine the organic matter type of the source rock in the mixed sedimentary rock sample. The organic matter type is type I kerogen, type II kerogen, and type III kerogen. The type II kerogen includes II-1 type kerogen and II-2 type kerogen. And classify the source rock into type I source rock, type II source rock, and type III source rock according to the organic matter type. The type II source rock includes II-1 type source rock and II-2 type source rock. The chart for judging the organic matter type in the mixed sedimentary rock according to the hydrogen index HI and the pyrolysis peak temperature T max is as shown in Figure 3 the figure.

[0066] Organic geochemical analysis of the mixed rocks in the Permian Lucaogou Formation in Jimusa'er Sag shows that the organic-rich mudstone laminations in the Lucaogou Formation are type I kerogen, with an average organic carbon content TOC of 5.70%, a free hydrocarbon content S1 of 0.86 mg / g, a pyrolysis hydrocarbon content S2 of 33.61 mg / g, and a pyrolysis peak temperature T max of 444 °C, and a hydrogen index HI of 589.55 mg HC / g TOC. According to the whole-rock XRD analysis, it is determined that the mineral content of the type I organic-rich mudstone is the highest for siderite, at 34.1%, followed by quartz, at 17.0%, dolomite at 15.9%, clay minerals at 11.4%, calcite at 9.0%, and a small amount of plagioclase at 5.6%, as Figure 4 shown in (a) below. In the carbonate rock laminations of the Lucaogou Formation, the dolomite content is 42.0%, the calcite content is 22.4%, the quartz content is 11.8%, and a small amount of plagioclase is 4.3%, as Figure 4 shown in (b) below. Therefore, based on the above organic geochemical and mineral content analyses, in this example, mudstone samples and carbonate rock samples with low maturity in the Lucaogou Formation that meet the above characteristics are selected for subsequent experimental simulations.

[0067] According to the lithology and lamination combination characteristics of the mixed rock samples, different geological conceptual models are established. According to the common lithology and lamination combination characteristics of the mixed rock samples, various geological conceptual models such as type I source rock laminations interbedded with clastic rock laminations, type I source rock laminations interbedded with carbonate rock laminations, clastic rock laminations interbedded with type I source rock laminations, and carbonate rock laminations interbedded with type II source rock laminations can be established, as Figure 5 shown.

[0068] In this example, according to the combination type of the typical mudstone laminations and carbonate rock laminations in the Lucaogou Formation, the carbonate rock laminations interbedded with organic-rich mudstone laminations are determined as the geological conceptual model for subsequent experimental simulations.

[0069] S102: Determine the current R of the mixed rock in the target layer o corresponding geological parameters at the depth. According to the geological parameters, determine the simulation experimental conditions.

[0070] Among them, the geological parameters include the actual formation fluid pressure and the thermal maturity parameters; the simulation experimental conditions include the experimental pressure, the experimental temperature, and the constant temperature time.

[0071] Determine the actual formation fluid pressure and the thermal maturity parameters at the current R of the mixed rock in the target layer of the study area o corresponding to the depth. According to the above geological parameters, set the experimental pressure, the experimental temperature, and the constant temperature time, where the experimental pressure is directly taken from the actual formation fluid pressure at the current R of the mixed rock in the target layer of the study area o corresponding to the depth.

[0072] Determine the simulation experiment conditions according to the current actual geological characteristics of the Permian Lucaogou Formation in Jimusa'er Sag. The current mixed sedimentary rocks in the Lucaogou Formation have entered the peak period of the oil generation window, and the corresponding R o is 0.9%. Based on the hydrocarbon generation simulation results of the single lithology source rocks in the Lucaogou Formation, a mathematical model between the experimental temperature and the measured R o is established, as shown in Figure 6 . It can be seen from the mathematical model that when the experimental temperature is 320 °C, the R o of the simulated sample is 0.9%. Based on this, in order to simulate the hydrocarbon generation and expulsion process of the mixed sedimentary rocks in the Lucaogou Formation from the low maturity stage to the current oil generation window, the experimental temperature in this embodiment is set to 320 °C, and the constant temperature time is 72 h. According to the measured DST results in the study area, the actual formation fluid pressure in the Lucaogou Formation is 39 MPa, and the corresponding static rock pressure is 84 MPa. Therefore, the experimental pressure for the hydrocarbon generation and expulsion simulation experiment is determined to be 39 MPa, and the static rock pressure is set to 84 MPa. It should be noted that this embodiment mainly simulates the hydrocarbon generation and expulsion process of the source rock laminar combination from low maturity to the current maturity conditions.

[0073] S103: Prepare the mixed sedimentary rock experimental samples according to the geological conceptual model.

[0074] Considering the heterogeneity of different lithologies and laminar combinations of the mixed sedimentary rocks in the target interval of the study area, first, the selected shallow low-maturity mixed sedimentary rock samples are prepared into single lithology samples (such as dolomite, siltstone, mudstone, limestone, etc.) according to the geological analysis results. Each single lithology sample is crushed to 40 - 60 mesh, and then a small portion is taken according to each experimental temperature and weighed according to the experimental model. Specifically, taking the preparation of the mixed sedimentary rock experimental sample with carbonate rock laminations intercalated with organic matter-rich mudstone laminations as an example, the carbonate rock sample and the organic matter-rich mudstone sample are first crushed to 40 - 60 mesh. Take 30 g of carbonate rock as the upper lamination, take 40 g of the organic matter-rich mudstone sample as the middle lamination, and take 30 g of carbonate rock sample as the lower lamination. The total of the three parts of the sample is 100 g.

[0075] S104: Load the mixed sedimentary rock experimental samples into the sample chamber of the hydrocarbon generation and expulsion simulation experimental device, and conduct the hydrocarbon generation and expulsion simulation of the mixed sedimentary rocks according to the simulation experiment conditions.

[0076] Taking the mixed sedimentary rock experimental sample with carbonate rock laminations intercalated with organic matter-rich muddy laminations as an example, it is loaded into the sample chamber in the order of the lower carbonate rock lamination section - the middle organic matter-rich mudstone lamination section - the upper carbonate rock lamination section. The organic matter-rich mudstone and the upper and lower carbonate rock laminations are separated by gaskets, as shown in Figure 7As shown. The gasket is a high-porosity and high-permeability gasket made of special inorganic materials. The gasket can prevent rock powders from mixing with each other. At the same time, the gasket has the characteristics of high porosity and high permeability, and only plays a role of physical isolation without affecting the hydrocarbon generation and expulsion process. A mixed sedimentary rock experimental sample is pressed into a small cylindrical core sample with a diameter of 3.5 cm under a certain mechanical pressure. The pressed columnar core sample represents the combined characteristics of mixed sedimentary rocks with different laminations in the weakly consolidated state at the early diagenetic stage.

[0077] Install the sample chamber in the autoclave and conduct an airtightness test. The process of the airtightness test is as follows: After pressure application and sealing, an inert gas is filled, the pressure is raised to 5 - 10 MPa and then kept stable, leakage detection is carried out, the airtightness is checked by monitoring the change of the pressure value in the sample chamber, and it is regarded as qualified for sealing if the pressure reading remains stable within 1 h. Repeat the above operations 3 - 5 times. After determining that the airtightness is qualified, release the gas, and finally evacuate the sample chamber.

[0078] Prepare the formation water for the experiment. The salinity of the formation water for the experiment is the same as that of the actual formation water of the mixed sedimentary rock sample. Inject the formation water for the experiment into the sample chamber so that the formation water for the experiment fills the pore space of the mixed sedimentary rock experimental sample, and keep the initial formation fluid pressure in the sample chamber at a certain value: The basic geological data of the study area shows that the actual formation water in the Permian Lucaogou Formation in Jimusa'er Sag is of the NaHCO3 type, with a salinity of 8723.61 mg / l. To simulate the actual geological conditions of the Permian Lucaogou Formation in Jimusa'er Sag, prepare the formation water for the experiment. The formation water for the experiment is sufficient NaHCO3-type water with the same salinity as the actual formation water in the Lucaogou Formation. Use a high-pressure pump to inject the formation water for the experiment into the sample chamber to completely fill the pore space of the pressed columnar core sample with the formation water for the experiment. In order to keep the limited hydrocarbon generation space filled with liquid formation water throughout the hydrocarbon generation and expulsion process and simulate the formation conditions to the maximum extent, keep the initial formation fluid pressure in the sample chamber at 2 - 3 MPa before pressurization and heating.

[0079] Then start pressurization and heating to simulate the hydrocarbon generation and expulsion characteristics of mixed sedimentary rocks during the process from weak consolidation to lithification under actual geological conditions. Apply a set lithostatic pressure to the mixed sedimentary rock experimental sample to simulate the lithostatic pressure suffered by the mixed sedimentary rock sample during hydrocarbon generation, expulsion and diagenesis; heat up at a set heating rate to a set experimental temperature, and after reaching the set temperature, maintain the set constant temperature time for hydrocarbon generation and expulsion simulation.

[0080] In this embodiment, the set heating rate is 1 °C / min, the set experimental temperature is 320 °C, and the set constant temperature time is 72 h.

[0081] When the formation fluid pressure in the sample chamber reaches the hydrocarbon expulsion pressure threshold, the hydrocarbon expulsion valve automatically opens to expel hydrocarbons. When the formation fluid pressure in the sample chamber returns to the actual formation fluid pressure, the hydrocarbon expulsion valve automatically closes, and during the entire hydrocarbon generation and expulsion process, the above hydrocarbon expulsion process is continuously repeated. The hydrocarbon expulsion pressure threshold is 1.2 times the actual formation fluid pressure.

[0082] In this embodiment, the actual formation fluid pressure of the Lucaogou Formation is 39 MPa. With continuous hydrocarbon generation, when the formation fluid pressure in the sample chamber reaches 1.2 times 39 MPa, that is, when the formation fluid pressure in the sample chamber reaches 46.8 MPa, the hydrocarbon expulsion valve automatically opens, and the fluid is discharged from the mixed sedimentary rock experimental sample. After hydrocarbon expulsion, the fluid pressure decreases and returns to 39 MPa, and the hydrocarbon expulsion valve automatically closes.

[0083] S105: Collect the products of the hydrocarbon generation and expulsion simulation and conduct a quantitative evaluation of hydrocarbon generation and expulsion. The products of the hydrocarbon generation and expulsion simulation include:

[0084] Expelled oil, which is the oil expelled from the mixed sedimentary rock series;

[0085] Injected oil, which is the oil injected into adjacent laminations after the hydrocarbon source rock lamination satisfies its own adsorption and reaches saturation;

[0086] Retained oil, which is the oil that has not undergone effective hydrocarbon expulsion and remains in the pore space of the hydrocarbon source rock lamination.

[0087] After the experiment, when the temperature of the entire simulation experiment device drops to 150 °C, open the hydrocarbon expulsion valve to discharge the oil-gas-water mixture in the simulation experiment device. First, conduct liquid nitrogen cooling, and then separate liquid oil, liquid water, and gaseous hydrocarbons in the liquid collection tube. The oil-water mixture is frozen in the collection tube, and the gas product enters the metering tube to measure its volume and then is collected. Since this application mainly simulates the hydrocarbon generation and expulsion process of mixed sedimentary rock within the oil generation window, the gas product is mainly non-hydrocarbon gas, and the generation amount of hydrocarbon gas is low. Therefore, this patent mainly conducts quantitative analysis on the liquid hydrocarbon products. Figure 8Schematic diagram for quantitative evaluation of hydrocarbon generation and expulsion products of mixed sedimentary rocks. In this embodiment, the expelled oil mainly consists of two parts: one part is the oil product frozen in the liquid collection tube; the other part is the expelled oil obtained by flushing the surface of the solid residue in the sample chamber, the surface of the gasket, the inner wall of the autoclave, and the hydrocarbon expulsion pipeline; among them, the sample chamber is flushed with dichloromethane. The charged oil is the oil charged into the carbonate laminae through hydrocarbon expulsion, and the retained oil is the oil remaining in the shale laminae after hydrocarbon expulsion. When calculating the amounts of the charged oil and the retained oil, it is necessary to first collect the remaining samples of the simulated shale laminae and carbonate laminae. Since the above remaining samples are separated by gaskets, each part can be quantitatively collected separately. Inevitably, a part of the remaining samples will be lost during the collection process. Therefore, in the calculation process, it is assumed that the distribution of oil in different laminae after the hydrocarbon generation and expulsion experiment is uniform. By separately crushing the remaining sample residues of each lamina collected, weighing them, and then extracting them with dichloromethane respectively, the amount of oil in the carbonate laminae in the mixed sedimentary rock experimental sample after hydrocarbon generation and expulsion is the amount of the charged oil, and the amount of oil in the shale laminae is the amount of the retained oil.

[0088] According to the hydrocarbon expulsion products of the hydrocarbon generation and expulsion simulation, calculate the hydrocarbon expulsion efficiency E. The calculation formula for the hydrocarbon expulsion efficiency E is:

[0089]

[0090] Among them, X1 is the amount of the expelled oil, X2 is the amount of the charged oil, and X3 is the amount of the retained oil. The units of the amounts of the expelled oil, the charged oil, and the retained oil are mg.

[0091] The part of the organic matter that remains in the shale laminae and does not have the ability to generate hydrocarbons is "dead carbon".

[0092] In this embodiment, after the mixed sedimentary rock with carbonate laminae interbedded with shale laminae is simulated at 320 °C for 72 h, the total amount of oil generated X1 + X2 + X3 is 1299.49 mg; the amount of the expelled oil X1 is 100.70 mg, the amount of oil discharged from the shale laminae into the upper carbonate laminae is 320.37 mg, and the amount of oil entering the lower carbonate laminae is 41.09 mg. The sum of the two is the amount of the charged oil X2, totaling 361.46 mg. Most of it remains inside the organic-rich shale, and the amount of the retained oil X3 is 837.33 mg; the calculated hydrocarbon expulsion efficiency is 35.56%. Table 1 is the statistical table of the experimental results of the hydrocarbon generation and expulsion simulation of the mixed sedimentary rock experimental sample with carbonate laminae interbedded with organic-rich shale laminae.

[0093] Table 1:

[0094] Parameter Name Result Unit Discharged Oil 100.70 mg Charged Oil 361.46 mg Retained Oil 837.33 mg Hydrocarbon Discharge Efficiency 35.56 ％

[0095] In view of the characteristics of continental mixed sedimentary rock series, such as complex composition, rapid lithological and lithofacies changes, and frequent interbedding, based on the actual geological conditions of the study area, organic geochemical analysis and mineral content analysis are carried out to determine the typical lithology and lamina combination of the target layer. Considering the differences in hydrocarbon generation and expulsion of different lithologies within the mixed sedimentary series, different geological conceptual models are established according to the typical lithology and lamina combination of the target layer, and hydrocarbon generation and expulsion simulation experiments are carried out under the actual formation temperature and pressure conditions to evaluate the hydrocarbon expulsion efficiency and hydrocarbon generation and expulsion volume of different types of mixed rocks, providing parameters and basis for the evaluation of oil and gas resources in oil and gas basins developed with mixed rocks.

[0096] Based on the ideas and methods of this application, it is also possible to simulate the hydrocarbon generation and expulsion characteristics and corresponding quantitative evaluation from the low-maturity stage to a higher maturity stage. The process is similar to the above description and will not be described in detail here.

[0097] Corresponding to the above embodiments, this application also provides a hydrocarbon generation and expulsion simulation experiment device.

[0098] See Figure 9 , which is a schematic structural diagram of a hydrocarbon generation and expulsion simulation experiment device provided by an embodiment of this application. As Figure 9 shown, it mainly includes the following structures:

[0099] High-temperature and high-pressure hydrocarbon generation reaction system, bidirectional hydraulic control system, hydrocarbon expulsion system, automatic control and data acquisition system, product separation and collection system, peripheral auxiliary equipment and instrument shell;

[0100] The high-temperature and high-pressure hydrocarbon generation reaction system includes a reaction kettle 1, a sample chamber 2, a gasket 3, an oil pump 4, a static rock pressure reduction device 5, a static rock pressure increase device 6, a static rock pressure monitoring device 7, a sealing pressure increase device 8, a sealing pressure reduction device 9, a formation fluid pressure monitoring device 10, a pressure compensation pump 11, a pressure compensator 12, and an in-kettle pressure compensation device 13;

[0101] The hydrocarbon expulsion system includes an upper hydrocarbon expulsion device 14, a lower hydrocarbon expulsion device 15, a pressure pump 16, a pressure increasing valve 17, a pressure reducing valve 18, and a hydrocarbon expulsion pressure control device 19;

[0102] The product separation and collection system includes an upper separation and collection system and a lower separation and collection system. The upper separation and collection system includes an upper gas-liquid separation valve 20, an upper gas-liquid separator 21, an upper collected gas pressure monitoring device 22, and an upper gas-liquid collector 23; the lower separation and collection system includes a lower gas-liquid separator 24, a lower collected gas pressure monitoring device 25, and a lower gas-liquid collector 26;

[0103] One path of the oil pump 4 is successively connected to the static rock pressure reducing device 5 and the static rock pressure increasing device 6 and is connected to the upper end of the sample chamber 2. Another path of the oil pump 4 is connected to the lower end of the sample chamber 2 through the sealing pressure increasing device 8 and the sealing pressure reducing device 9. The static rock pressure monitoring device 7 is connected between the static rock pressure increasing device 6 and the sample chamber 2. The upper hydrocarbon discharging device 14 is connected to the upper end of the sample chamber 2, and the lower hydrocarbon discharging device 15 is connected to the lower end of the sample chamber 2. The formation fluid pressure monitoring device 10 is connected to the line between the upper hydrocarbon discharging device 14 and the sample chamber 2. The pressure pump 16 is connected to the line between the upper hydrocarbon discharging device 14 and the upper gas-liquid separation valve 20 through the pressure increasing valve 17 and the pressure reducing valve 18. The hydrocarbon discharging pressure control device 19 is connected to the line between the pressure increasing valve 17 and the pressure reducing valve 18 and the line between the upper hydrocarbon discharging device 14 and the upper gas-liquid separation valve 20. The upper separation and collection system is connected to the upper hydrocarbon discharging device 14, and the lower separation and collection system is connected to the lower hydrocarbon discharging device 15. One end of the pressure compensating device 13 inside the kettle is connected between the lower hydrocarbon discharging device and the sample chamber 2, and the other end of the pressure compensating device 13 inside the kettle is connected to the pressure compensator 12, and the pressure compensator 12 is connected to the pressure compensating pump 11.

[0104] Wherein, the gasket is a high-porosity and high-permeability gasket made of a special inorganic material.

[0105] The above is only the specific implementation manner of the present application. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. The protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for simulating hydrocarbon generation and expulsion, characterized in that Comprising: Based on the mixed sedimentary rock samples of the target layer, a geological conceptual model is established. The mixed sedimentary rock samples include source rocks and non-source rocks; Determine the current R of the mixed sedimentary rock in the target layer o Geological parameters at the corresponding depth, and determine the simulation experiment conditions according to the geological parameters; According to the geological conceptual model, experimental samples of mixed sedimentary rocks are prepared; The experimental samples of mixed sedimentary rocks are loaded into the sample chamber of the hydrocarbon generation and expulsion simulation experimental device, and according to the simulation experimental conditions, hydrocarbon generation and expulsion simulation of the mixed sedimentary rocks is carried out; The products of the hydrocarbon generation and expulsion simulation are collected, and quantitative evaluation of hydrocarbon generation and expulsion is carried out.

2. The method according to claim 1, wherein Based on the mixed sedimentary rock samples of the target layer, a geological conceptual model is established. The mixed sedimentary rock samples include source rocks and non-source rocks, including: Obtain various mixed sedimentary rock samples of the target layer; Carry out organic geochemistry and mineral content analysis on the mixed sedimentary rock samples to determine the lithology and lamination combination characteristics of the mixed sedimentary rock samples; According to the lithology and lamination combination characteristics of the mixed sedimentary rock samples, different geological conceptual models are established.

3. The method according to claim 2, wherein Determine the lithology of the source rock, including: Determine the basic geochemical parameters of the mixed sedimentary rock sample, where the basic geochemical parameters include total organic carbon content TOC, hydrogen index HI, and pyrolysis peak temperature T max ; According to the total organic carbon content TOC, the mixed sedimentary rock samples are divided into rich organic matter mixed sedimentary rocks, high organic matter mixed sedimentary rocks, medium organic matter mixed sedimentary rocks and poor organic matter mixed sedimentary rocks; Based on the hydrogen index HI and the pyrolysis peak temperature T max , determine the organic matter type of the source rock in the mixed sedimentary rock sample, and classify the source rock into type I source rock, type II source rock, and type III source rock according to the organic matter type.

4. The method according to claim 1, wherein The geological parameters include actual formation fluid pressure and thermal maturity parameters; the simulation experimental conditions include experimental pressure, experimental temperature and constant temperature time.

5. The method according to claim 1, wherein The step of loading the experimental samples of mixed sedimentary rocks into the sample chamber of the hydrocarbon generation and expulsion simulation experimental device and carrying out hydrocarbon generation and expulsion simulation of the mixed sedimentary rocks according to the simulation experimental conditions includes: Load the experimental samples of mixed sedimentary rocks into the sample chamber of the hydrocarbon generation and expulsion simulation experimental device, install the sample chamber in the reaction kettle, carry out airtightness test, and after the airtightness is qualified, evacuate the sample chamber; Prepare experimental formation water, inject the experimental formation water into the sample chamber, so that the experimental formation water fills the pore space of the experimental samples of mixed sedimentary rocks, and keep the initial formation fluid pressure of the sample chamber at a certain value; Apply a set confining pressure to the experimental samples of mixed sedimentary rocks, heat up to the set experimental temperature at the set heating rate, maintain the set constant temperature time, and carry out hydrocarbon generation and expulsion simulation; When the formation fluid pressure in the sample chamber reaches the hydrocarbon expulsion pressure threshold, the hydrocarbon expulsion valve automatically opens and expels hydrocarbons. When the formation fluid pressure in the sample chamber returns to the actual formation fluid pressure, the hydrocarbon expulsion valve automatically closes, and the above hydrocarbon expulsion process is repeated.

6. The method according to claim 1, characterized in that, The products of the hydrocarbon generation and expulsion simulation include: Expelled oil, which is the oil expelled from the mixed sedimentary rock series; Injected oil, which is the oil injected into the adjacent laminae when the source rock laminae satisfy their own adsorption and reach saturation; Retained oil, which is the oil that has not undergone effective hydrocarbon expulsion and remains in the pore space of the source rock laminae.

7. The method according to claim 1, characterized in that The step of collecting the products of the hydrocarbon generation and expulsion simulation and carrying out quantitative evaluation of hydrocarbon generation and expulsion includes calculating the hydrocarbon expulsion efficiency E according to the products of the hydrocarbon generation and expulsion simulation. The calculation formula of the hydrocarbon expulsion efficiency E is: Wherein, X1 is the amount of expelled oil, X2 is the amount of injected oil, and X3 is the amount of retained oil.

8. The method according to claim 7, wherein The calculation methods for the amount of injected oil and the amount of retained oil are as follows: The remaining sample residues of each laminar layer collected are respectively crushed, weighed, and then extracted with dichloromethane. The amount of oil in the non-source rock laminar layer of the experimental sample of the mixed sedimentary rock after hydrocarbon generation and expulsion is the amount of injected oil, and the amount of oil in the source rock laminar layer is the amount of retained oil.

9. An apparatus for the method of generating and expelling hydrocarbon simulation experiment according to any one of claims 1-8, characterized in that, The device includes: a high-temperature and high-pressure hydrocarbon generation reaction system, a two-way hydraulic control system, a hydrocarbon expulsion system, an automatic control and data acquisition system, a product separation and collection system, peripheral auxiliary equipment, and an instrument housing; The high-temperature and high-pressure hydrocarbon generation reaction system includes a reaction kettle (1), a sample chamber (2), a gasket (3), an oil pump (4), a static rock decompression device (5), a static rock pressurization device (6), a static rock pressure monitoring device (7), a sealing pressurization device (8), a sealing decompression device (9), a formation fluid pressure monitoring device (10), a pressure compensation pump (11), a pressure compensator (12), and an in-kettle pressure compensation device (13); The hydrocarbon expulsion system includes an upper hydrocarbon expulsion device (14), a lower hydrocarbon expulsion device (15), a pressure pump (16), a pressure increasing valve (17), a pressure reducing valve (18), and a hydrocarbon expulsion pressure control device (19); The product separation and collection system includes an upper separation and collection system and a lower separation and collection system. The upper separation and collection system includes an upper gas-liquid separation valve (20), an upper gas-liquid separator (21), an upper collected gas pressure monitoring device (22), and an upper gas-liquid collector (23); The lower separation and collection system includes a lower gas-liquid separator (24), a lower collected gas pressure monitoring device (25), and a lower gas-liquid collector (26); One path of the oil pump (4) is sequentially connected to the static rock pressure reducing device (5) and the static rock pressure increasing device (6) and is connected to the upper end of the sample chamber (2). Another path of the oil pump (4) is connected to the lower end of the sample chamber (2) through the sealing pressure increasing device (8) and the sealing pressure reducing device (9). The static rock pressure monitoring device (7) is connected between the static rock pressure increasing device (6) and the sample chamber (2). The upper hydrocarbon discharging device (14) is connected to the upper end of the sample chamber (2), and the lower hydrocarbon discharging device (15) is connected to the lower end of the sample chamber (2). The formation fluid pressure monitoring device (10) is connected to the line between the upper hydrocarbon discharging device (14) and the sample chamber (2). The pressure pump (16) is connected to the line between the upper hydrocarbon discharging device (14) and the upper gas-liquid separation valve (20) through the pressure increasing valve (17) and the pressure reducing valve (18). The hydrocarbon discharging pressure control device (19) is connected to the line between the pressure increasing valve (17) and the pressure reducing valve (18) and the line between the upper hydrocarbon discharging device (14) and the upper gas-liquid separation valve (20). The upper separation and collection system is connected to the upper hydrocarbon discharging device (14), and the lower separation and collection system is connected to the lower hydrocarbon discharging device (15). One end of the pressure compensating device inside the kettle (13) is connected between the lower hydrocarbon discharging device and the sample chamber (2), the other end of the pressure compensating device inside the kettle (13) is connected to the pressure compensator (12), and the pressure compensator (12) is connected to the pressure compensating pump (11).

10. The device according to claim 9, wherein, The gasket is a high-porosity and high-permeability gasket made of inorganic materials.

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