A dynamic imbibition device and method for simulating the temperature and pressure conditions of a dense oil reservoir throughout the whole process

Abstract

The application relates to a dynamic imbibition device and method for simulating temperature and pressure conditions of a whole dense oil reservoir, and belongs to the technical field of dense sandstone reservoir development, in particular to a dynamic imbibition device and method for simulating temperature and pressure conditions of a whole dense oil reservoir. The device comprises a core clamping cylinder, a sealing cover plate, a sealing ring, a matrix core to be measured and a prefabricated fracture partition plate located between the two matrix cores to be measured. The method comprises the following steps: S1, preparation; S2, saturating the matrix core with crude oil; and S3, fracture water injection dynamic imbibition. The application can keep the dense sandstone reservoir dynamic imbibition experiment warm and pressurized, and can open the fracture during the process of keeping warm and pressurized, so that the imbibition mode of the dense sandstone reservoir can be simulated, the real formation conditions can be highly restored, and the simulation experiment research on the dynamic imbibition is promoted.

Description

Technical Field

[0001] This invention relates to the field of tight sandstone reservoir development technology, specifically to a dynamic percolation device and method that fully simulates the temperature and pressure conditions of tight reservoirs. Background Technology

[0002] In foreign literature, "tight oil" is not a precise term; different researchers and institutions have different definitions. However, it is generally emphasized that tight oil is an unconventional petroleum resource, characterized by its light weight and production layers consisting of extremely low-permeability siltstone, sandstone, or carbonate rocks. Tight reservoirs are closely associated with organic-rich source rocks and are extracted using special methods such as horizontal wells and volumetric fracturing. In my country, tight oil is typically defined as oil stored in overburden matrices with permeability less than or equal to 0.1 × 10⁻⁶ m³ / s. -3 μm 2 (Air permeability less than 1×10) -3 μm 2 Oil is found in reservoirs such as tight sandstone and tight carbonate rocks. Single wells generally have no natural production capacity or a natural production capacity below the lower limit of industrial oil flow, but industrial oil production can be achieved under certain economic conditions and technical measures. These measures typically include acid fracturing, multi-stage fracturing, horizontal wells, and multi-branch wells.

[0003] my country is rich in tight oil resources. In recent years, significant progress has been made in the development of tight oil reservoirs in the Upper Triassic Yanchang Formation of the Ordos Basin, the Qingshankou Formation of the Songliao Basin, the Shahejie Formation of the Qikou Depression in the Bohai Bay Basin, the Permian Fengcheng Formation and Lucaogou Formation of the Mahu and Jimusar Depressions in the Junggar Basin, the Shuixigou Group of the Qiudong Depression in the Turpan-Hami Basin, and the Lower Youshashan Formation of the Fengxi Area in the Qaidam Basin. Preliminary identification of favorable tight oil-bearing areas covers approximately 16 × 10⁻⁶ square kilometers. 4 km 2 Geological reserves are approximately 200 × 10 8 my country has made significant technological explorations into how to efficiently and economically develop tight oil reservoirs. These include well type and pattern optimization, field trials of natural energy extraction, pre-injection of water into low-pressure reservoirs, pilot tests of horizontal well recharge, polymer profile control, and tertiary oil recovery. While some progress has been made, development is hampered by numerous inherent factors such as the complex pore structure, diverse and varied flow channels, and strong heterogeneity of tight reservoirs. Problems frequently arise during development, including difficulty in injection and production, susceptibility to water flooding and gas channeling, and poor economic efficiency of chemical agents. Based on these issues, a "pressure-injection-steaming-production" technology, leveraging capillary force (percolation), has been proposed to improve the cumulative oil production of a single well throughout its entire lifecycle.

[0004] Irradiation is a widespread phenomenon in reservoir engineering, soil physics, water resources engineering, and many other fields. Since the early 20th century, the statics and dynamics of irradiation have attracted considerable attention from researchers. Early research on irradiation-driven oil displacement in petroleum engineering primarily focused on fractured reservoirs. In these reservoirs, the high conductivity of fractures led to less than ideal water injection development results. However, by appropriately reducing the flow velocity of injected water in the fractures, the capillary force of the reservoir matrix was fully utilized for irradiation-driven oil displacement, achieving better development results. As oil and gas development has shifted from conventional to unconventional methods, more and more scholars have turned their attention to the study of irradiation-driven oil displacement in tight reservoirs. The small pore throat radius, high capillary force, and hydrophilic wetting characteristics of tight reservoir matrix provide excellent inherent advantages for irradiation-driven oil displacement. Fracturing, as a necessary means of developing tight reservoirs, alters the seepage channels and patterns in fracture-controlled areas, making artificial fractures the dominant seepage channels in tight reservoirs. Conducting dynamic irradiation studies based on full-size core samples is of great significance and practical value for the efficient development of tight reservoirs.

[0005] Currently, most domestic research on percolation focuses on static percolation. Some scholars have modified or combined mature experimental equipment to complete research on dynamic percolation. For example, patent publication number CN109459556B discloses a dynamic percolation device and an experimental method for dynamic percolation experiments. The dynamic percolation device includes: a base and a shell, with a pressure port on the shell for applying pressure to the interior; a stirring module, located inside the shell, for stirring the experimental liquid inside the shell to keep the liquid in a dynamic flow state; a fixing device, located inside the shell, for fixing the experimental sample; a percolation bottle, located inside the shell, including a cover and a measuring tube, the cover for covering the experimental sample, where oil droplets in the sample float to the measuring tube under the action of capillary force and gravity; and a processing module for controlling the stirring speed of the stirring module. This invention patent can shield the displacement effect and only study the dynamic percolation phenomenon. However, this device and method actually have the following problems: 1. This experimental method completely immerses core samples with a diameter of 2.5cm to 4.0cm in the permeate, assuming that the core end face and side face are in complete contact with the permeate (simulating complete contact between the matrix and fractures, or that the matrix is ​​completely surrounded by fractures). However, actual field testing has shown that this condition is too idealistic and deviates significantly from reality (based on actual core samples from artificial fracture detection wells). Furthermore, previous research indicates that the size and method of contact area directly affect the permeate recovery rate, and the experimental data obtained by this method will be generally optimistic. 2. This device uses a stirrer to make the permeate flow around the core, placing the core in a dynamic flow environment. From actual field testing and laboratory experiments, it is known that dynamic permeation usually refers to the macroscopic reflection of the permeate flow in fractures and the permeation coupling effect under fracture-pore pressure difference and capillary force. One of the purposes of conducting dynamic permeation model experiments and research is to obtain the optimal water drive front velocity and corresponding pressure gradient under simulated reservoir conditions, and then convert it into actual water injection pressure or drainage velocity in the field. However, this experimental device cannot achieve the above goals.

[0006] In addition, other commonly used dynamic percolation experimental devices generally have the following drawbacks: 1. The vacuum saturation method cannot completely guarantee that all pores are saturated with crude oil in tight sandstone reservoir experiments; 2. Artificial fracture creation after saturating the matrix core with oil can lead to changes in the pore structure due to factors such as stress release, which in turn can cause errors in the experimental data. 3. Currently, the standard core sample size used in mainstream laboratories is relatively small (2.5 cm in diameter, maximum length 12 cm). If long core model experiments are required, multiple cores need to be spliced ​​together. Tight reservoirs have strong heterogeneity, and the selection of core properties and combination methods in this method has a high degree of randomness. Therefore, there is a certain degree of error compared to experimental results obtained using full-size cores. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a dynamic percolation device and method for simulating the temperature and pressure conditions of tight oil reservoirs throughout the entire process.

[0008] The technical solution of this invention is: A dynamic seepage device that simulates the temperature and pressure conditions of a tight oil reservoir throughout the entire process includes a cylindrical core holding cylinder with openings at both ends, a sealing cover plate at the front end of the core holding cylinder, an annular sealing ring at the rear end of the core holding cylinder, two semi-cylindrical matrix cores to be tested arranged symmetrically inside the core holding cylinder, and a prefabricated fracture partition plate between the two matrix cores to be tested. Two matrix cores to be tested are respectively fixedly connected at their rear ends with a sealing block, and the prefabricated fracture partition is respectively fixedly connected at its rear end with a sealing plate. The diameter of the rear end of the sealing block is 1.2 to 1.5 times the diameter of the front end. The size of the rear end of the sealing plate matches the size of the rear end of the sealing block. The rear ends of the sealing block and the sealing plate are connected to each other and spliced ​​into a circle. Each of the two sealing blocks is provided with a matrix core liquid guiding tube. The front ends of the two matrix core liquid guiding tubes pass through the sealing block and are respectively connected to the rear ends of the two matrix cores to be tested. The sealing plate is provided with several fracture liquid guiding tubes. The front ends of the fracture liquid guiding tubes pass through the sealing plate and are connected to the prefabricated fracture partition. The sealing cover plate has two first injection pipes on both sides, and the sealing cover plate has several second injection pipes corresponding to the precast crack partition at its center. The two first injection pipes correspond to two matric cores to be tested. A rubber sleeve is provided between the outside of the matric core to be tested and the inner wall of the core clamping cylinder. The rubber sleeve wraps around the front end of the sealing block and the sealing plate. A confining pressure pipe is provided at the top of the core clamping cylinder, and a confining pressure relief pipe is provided on one side of the core clamping cylinder. The prefabricated crack partition has symmetrical grooves on both sides of the middle part. The inside of the grooves is an artificial quartz sandstone slab with flow guiding capacity. A pull plate is slidably connected to each of the two grooves. The rear end of the pull plate passes through the guide groove provided inside the sealing plate and extends out of the inner diameter of the sealing ring. The front end of the pull plate is flush with the front end of the prefabricated crack partition.

[0009] Furthermore, the sealing cover and sealing ring are detachably connected to the internal threads at both ends of the outer surface of the core clamping cylinder. After the sealing cover is tightened, the first injection pipe and the second injection pipe are exactly in the designated position. The rear end of the sealing cover extends into the interior of the core clamping cylinder and is wrapped by the rubber sleeve.

[0010] Furthermore, the sealing block has several limiting blocks at equal intervals on its side wall. The limiting blocks are engaged one-to-one with several limiting slots at the rear end of the core clamping cylinder. The diameter of the rear end of the sealing block is 1.2 times the diameter of the core matrix to be tested.

[0011] Note: The sealing block and the test matrix core are tightly fitted by the connection of the limiting card block and the limiting card slot.

[0012] Furthermore, there are 3 fracture fluid guiding pipes on each side of the extraction plate, 3 second fluid injection pipes, 2 first fluid injection pipes arranged left and right with one high and one low, 2 matrix core fluid guiding pipes arranged left and right with one high and one low, and the first fluid injection pipes and matrix core fluid guiding pipes on the same matrix core to be tested are arranged front and back with one high and one low.

[0013] Explanation: By adjusting the inlet and outlet positions at different heights, the interior of the matrix core to be tested is fully saturated with simulated formation water and simulated formation oil, thus simulating a more realistic reduced oil reservoir situation.

[0014] Furthermore, each of the two sealing blocks has a positioning groove on its inner sidewall, and a spring positioning plate is provided inside the positioning groove. One side of the spring positioning plate abuts against the sidewall of the sealing plate to assist in positioning the sealing plate.

[0015] Furthermore, the two drawer plates are driven to slide by an external servo motor push rod, and the output shaft of the servo motor push rod is fixedly connected to the end of the drawer plate.

[0016] This invention also provides a dynamic percolation method that fully simulates the temperature and pressure conditions of a tight oil reservoir, based on any one of the aforementioned dynamic percolation devices that fully simulate the temperature and pressure conditions of a tight oil reservoir, comprising the following steps: S1. Preparation: The complete full-diameter core samples are processed to the specified dimensions according to experimental requirements, washed with oil in a core washing apparatus, and then dried at 100℃ for 48 hours. The porosity and permeability of the matrix core are measured using a full-diameter core porosity-permeability analyzer. The cylindrical core is cut into two semi-cylindrical matrix cores using a high-speed wire cutting machine. The two semi-cylindrical matrix cores are placed on the left and right sides of the core clamping cylinder, respectively. Then, the etched pre-fabricated fracture partition is placed in, followed by the placement of the sealing block and sealing plate to position the matrix core and the pre-fabricated fracture partition. The two extraction plates are placed in the groove through the guide groove. A servo motor push rod is installed at the rear end of the extraction plate. Then, the sealing cover plate and sealing ring are installed in sequence. The entire device is then sealed. Water is injected through the confining pressure pipe to squeeze the rubber sleeve so that the external confining pressure of the matrix core reaches the confining pressure set in the experiment. The confining pressure range of this device is 10~40MPa. The constant temperature chamber is opened and adjusted to simulate the reservoir temperature. S2, Saturated Crude Oil in Matrix Core: Simulated formation water is slowly injected through two first injection tubes to completely saturate the two semi-cylindrical matrix cores with simulated formation water. Then, simulated formation oil is slowly injected to completely saturate the two matrix cores to be tested with simulated formation oil. The discharged simulated formation water and simulated formation oil are collected through two matrix core liquid guide tubes. When the amount of liquid discharged reaches 3~5PV, the core is considered to be completely saturated. S3. Dynamic seepage of water through fractures: The servo motor push rod is activated to pull the two extraction plates backward a certain distance, ensuring that the front end of the extraction plates is in the guide groove. The extraction speed is 0.5~2cm / 5s. The simulated fracture on the prefabricated fracture partition opens, and then tap water is injected through the second injection pipe at a speed of 5~100ml / min to simulate the dynamic seepage process. The simulated formation water and simulated formation oil discharged through the fracture guide pipe are collected.

[0017] Furthermore, the upper and lower parts of the prefabricated crack partition in S1 are made of hard alloy, so that the artificial quartz sandstone slab inside the groove of the prefabricated crack partition forms a prefabricated simulated crack with interconnected pores. The width of the prefabricated crack partition at the location of the artificial quartz sandstone slab is 0.5~2cm, and the width of the prefabricated crack partition at other locations is 1~3cm.

[0018] Description: By creating prefabricated simulated cracks with interconnected pores in the artificial quartz sandstone slab inside the groove of the prefabricated crack partition, the permeability can be adjusted.

[0019] Furthermore, the simulated formation water in S2 has a salinity of 5000~50000 mg / L, and the simulated formation oil has a viscosity of 1~5 mPa / s.

[0020] The beneficial effects of this invention are: (1) The dynamic permeation device and method of the present invention simulates the temperature and pressure conditions of tight oil reservoirs throughout the entire process of dynamic permeation experiment of tight sandstone oil reservoirs by keeping the temperature and pressure maintained throughout the process and realizing the opening of cracks during the temperature and pressure maintenance process, thereby truly simulating the permeation mode of tight sandstone oil reservoirs and highly restoring the real formation conditions, which has played an important role in promoting the simulation experiment research of dynamic permeation.

[0021] (2) The dynamic permeation device of the present invention, which simulates the temperature and pressure conditions of tight oil reservoirs throughout the process, is designed to cooperate with prefabricated fracture partitions and extraction plates. At the same time, the sealing blocks and sealing plates can extract the extraction plates under the full-process sealed, heat-preserving and pressure-preserving conditions, thereby completing the formation of simulated fractures between two matrix cores to be tested. This makes up for the problem that artificial fractures cause stress damage to the cores and thus generate errors in the current dynamic permeation indoor experimental devices. The accuracy of experimental data is greatly improved, which has certain guiding significance for subsequent research on dynamic permeation.

[0022] (3) The dynamic percolation method of the present invention, which simulates the temperature and pressure conditions of tight oil reservoirs throughout the process, provides a complete set of experimental methods based on the device of the present invention. It gives clear limits on key parameters such as the flow capacity of the "fracture-pore", fluid characteristics, and water injection rate. This is an unprecedented attempt in previous studies and provides new ideas for indoor and field research on dynamic percolation of tight oil reservoirs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of a dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir throughout the entire process, according to the present invention.

[0024] Figure 2 This is a schematic diagram of the front-end structure of a dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir throughout the entire process, according to the present invention.

[0025] Figure 3 This is a schematic diagram of the internal structure of the core support cylinder of a dynamic seepage device that simulates the temperature and pressure conditions of a tight oil reservoir throughout the entire process, omitting the sealing cover and sealing ring.

[0026] Figure 4 This is a schematic diagram of the front end structure of the core support cylinder of a dynamic seepage device that simulates the temperature and pressure conditions of a tight oil reservoir throughout the entire process, omitting the sealing cover plate and sealing ring.

[0027] Figure 5 This is a right-side side view of a dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir throughout the entire process, according to the present invention.

[0028] Figure 6 This is a schematic diagram of the spring positioning plate structure of a dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir throughout the entire process, according to the present invention.

[0029] Figure 7 This is a schematic diagram of the internal structure of a dynamic seepage device for simulating the temperature and pressure conditions of a tight oil reservoir throughout the entire process, omitting the core support cylinder.

[0030] Figure 8 This is a top view of a dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir, as described in this invention, connected to an external servo motor.

[0031] Figure 9 This is a left-side view of a dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir throughout the entire process, according to the present invention.

[0032] Figure 10 This is an internal cross-sectional view of a dynamic percolation device that simulates the temperature and pressure conditions of a tight oil reservoir throughout the entire process, according to the present invention.

[0033] Figure 11 This is a side view of the sealing cover plate of a dynamic percolation device that simulates the temperature and pressure conditions of a tight oil reservoir throughout the entire process, according to the present invention.

[0034] Figure 12 This is a schematic diagram of the overall structure of a dynamic percolation device that simulates the temperature and pressure conditions of a tight oil reservoir throughout the entire process, when applied to the method of this invention.

[0035] Among them, 1-core clamping cylinder, 11-sealing cover plate, 12-sealing ring, 131-first injection pipe, 132-second injection pipe, 14-rubber sleeve, 15-containment pressure increasing pipe, 16-containment pressure relieving pipe, 17-limiting slot, 2-core matrix to be tested, 3-prefabricated fracture partition, 31-groove, 4-sealing block, 41-core matrix liquid guiding pipe, 42-limiting block, 43-positioning groove, 44-spring positioning plate, 5-sealing plate, 51-fracture liquid guiding pipe, 52-guide groove, 6-extraction plate, 7-servo motor push rod. Detailed Implementation

[0036] Example 1 like Figure 1 , Figure 7 and Figure 11 As shown, a dynamic seepage device that simulates the temperature and pressure conditions of a tight oil reservoir throughout the entire process includes a cylindrical core holding cylinder 1 with openings at both ends, a sealing cover plate 11 located at the front end of the core holding cylinder 1, an annular sealing ring 12 located at the rear end of the core holding cylinder 1, the sealing cover plate 11 and the sealing ring 12 being detachably connected to the internal threads provided at both ends of the outer surface of the core holding cylinder 1, two semi-cylindrical matrix cores 2 to be tested symmetrically arranged inside the core holding cylinder 1, and a prefabricated fracture partition plate 3 located between the two matrix cores 2 to be tested; like Figures 2-7 As shown, a sealing block 4 is fixedly connected to the rear end of each of the two test matrix cores 2, and a sealing plate 5 is fixedly connected to the rear end of the prefabricated fracture partition 3. The rear end surface area of ​​the sealing block 4 is increased, and six limiting blocks 42 are evenly spaced on the side wall of the sealing block 4. The limiting blocks 42 are engaged one-to-one with the six limiting slots 17 provided at the rear end of the core clamping cylinder 1. The rear end surface area of ​​the sealing plate 5 is increased, and the rear end area of ​​the sealing block 4 is 1.2 times the area of ​​the test matrix core 2. The rear ends of the sealing block 4 and the sealing plate 5 are connected and spliced ​​into a circle, with the ends of the two sealing blocks 4 separated. A matrix core fluid guide tube 41 is provided. The front ends of the two matrix core fluid guide tubes 41 pass through the sealing block 4 and are connected to the rear ends of the two matrix cores 2 to be tested, respectively. The end of the sealing plate 5 is provided with 6 fracture fluid guide tubes 51. There are 3 fracture fluid guide tubes 51 on each side of the extraction plate 6. The front ends of the fracture fluid guide tubes 51 pass through the sealing plate 5 and are connected to the prefabricated fracture partition 3. Each of the two sealing blocks 4 has a positioning groove 43 on its inner sidewall. A spring positioning plate 44 is provided inside the positioning groove 43. One side of the spring positioning plate 44 abuts against the sidewall of the sealing plate 5 to assist in positioning the sealing plate 5. like Figures 2-7As shown, two first injection pipes 131 are provided on both sides of the sealing cover plate 11, and three second injection pipes 132 are provided at the center of the sealing cover plate 11 corresponding to the precast crack partition 3. The two first injection pipes 131 correspond to two matrix cores 2 to be tested, respectively. After the sealing cover plate 11 is tightened, the first injection pipes 131 and the second injection pipes 132 are exactly in the designated positions. The rear end of the sealing cover plate 11 extends into the core clamping cylinder 1 and is wrapped by the rubber sleeve 14. The two first injection pipes 131 are divided into left and right sections. The two matrix core liquid guiding pipes 41 are set up with one high and one low, and the first liquid injection pipe 131 and the matrix core liquid guiding pipe 41 on the same matrix core 2 are set up with one high and one low, and the outer side of the matrix core 2 is set up with one high and one low, and the inner side of the core clamping cylinder 1 is provided with a rubber sleeve 14. The rubber sleeve 14 also wraps the front end of the sealing block 4 and the sealing plate 5. The top of the core clamping cylinder 1 is provided with a confining pressure and pressurizing pipe 15, and the side of the core clamping cylinder 1 is provided with a confining pressure and pressure relief pipe 16. like Figure 7 and Figure 10 As shown, the precast crack partition 3 has symmetrical grooves 31 on both sides of the middle. The inside of the grooves 31 is an artificial quartz sandstone plate with flow guiding capacity. A pull plate 6 is slidably connected to each of the two grooves 31. The rear end of the pull plate 6 passes through the guide groove 52 inside the sealing plate 5 and extends out of the inner diameter of the sealing ring 12. The front end of the pull plate 6 is flush with the front end of the precast crack partition 3. like Figure 8 As shown, the two drawer plates 6 are driven to slide by an external servo motor push rod 7, and the output shaft of the servo motor push rod 7 is fixedly connected to the end of the drawer plate 6.

[0037] Example 2 The difference between this embodiment and Embodiment 1 is that: The center of the sealing cover plate 11 is provided with four second injection pipes 132 corresponding to the precast crack partition plate 3, and the end of the sealing plate 5 is provided with eight crack liquid guiding pipes 51. There are four crack liquid guiding pipes 51 on each side of the extraction plate 6.

[0038] Example 3 The difference between this embodiment and Embodiment 1 is that: The sealing cover plate 11 has 5 second injection pipes 132 corresponding to the precast crack partition plate 3 at its center, and the sealing plate 5 has 10 crack liquid guiding pipes 51 at its end. There are 5 crack liquid guiding pipes 51 on each side of the extraction plate 6.

[0039] Example 4 This embodiment provides a dynamic percolation method that fully simulates the temperature and pressure conditions of a tight oil reservoir, based on a dynamic percolation device that fully simulates the temperature and pressure conditions of a tight oil reservoir in Embodiment 1, such as... Figure 12 As shown, it includes the following steps: S1. Preparation: The complete full-diameter core samples were processed to the specified dimensions according to experimental requirements, washed with oil in a core washing apparatus, and then dried at 100℃ for 48 hours. The porosity and permeability of the matrix core were measured using a full-diameter core porosity-permeability analyzer. The cylindrical core was then cut into two semi-cylindrical matrix cores using a high-speed wire cutting machine. Two semi-cylindrical test matrix cores 2 are placed inside the core clamping cylinder 1 on the left and right sides respectively. Then, the etched prefabricated crack partition 3 is placed in. The upper and lower parts of the prefabricated crack partition 3 are made of hard alloy, so that the artificial quartz sandstone plate inside the groove 31 of the prefabricated crack partition 3 forms a prefabricated simulated crack with interconnected pores. The width of the prefabricated crack partition 3 at the location of the artificial quartz sandstone plate is 1cm, and the width of the prefabricated crack partition 3 at other locations is 2cm. Then, the sealing block 4 and sealing plate 5 are placed to position the test matrix core 2 and the prefabricated crack partition 3. The two extraction plates 6 are placed in the groove 31 through the guide groove 52. The servo motor push rod 7 is installed at the rear end of the extraction plate 6. Then, the sealing cover plate 11 and sealing ring 12 are installed in sequence. Then, the entire device is sealed inside. Water is injected through the confining pressure pipe 15 to squeeze the rubber sleeve 14 so that the external confining pressure of the test matrix core 2 reaches 15MPa. S2, Matrix core saturated with crude oil: Simulated formation water is slowly injected through two first injection pipes 131. The salinity of the simulated formation water is 20000 mg / L, and the viscosity of the simulated formation oil is 5 mPa / s, so that the two matrix cores 2 to be tested are completely saturated with simulated formation water. Then, simulated formation oil is slowly injected to completely saturate the two matrix cores 2 to be tested with simulated formation oil. The discharged simulated formation water and simulated formation oil are collected through two matrix core liquid guide pipes 41 respectively. When the liquid output reaches 3~5 PV, the core is considered to be completely saturated. S3, Dynamic seepage of water through fractures: The servo motor push rod 7 is activated to pull the two extraction plates 6 backward a certain distance and ensure that the front end of the extraction plates 6 is in the guide groove 52. The extraction speed is 1cm / 5s. The simulated fracture on the prefabricated fracture partition 3 is opened. Then, tap water is injected through the second injection pipe 132 at a water injection speed of 60ml / min to simulate the dynamic seepage process. The simulated formation water and simulated formation oil discharged through the fracture guide pipe 51 are collected.

[0040] Example 5 The difference between this embodiment and embodiment 4 is that: The width of the precast crack partition 3 at the location of the artificial quartz sandstone slab is 0.5cm, and the width of the precast crack partition 3 at other locations is 1cm. Water is injected through the confining pressure pipe 15 to squeeze the rubber sleeve 14 so that the external confining pressure of the matrix core 2 to be tested reaches 10MPa.

[0041] Example 6 The difference between this embodiment and embodiment 4 is that: The width of the precast crack partition 3 at the location of the artificial quartz sandstone slab is 2cm, and the width of the precast crack partition 3 at other locations is 3cm. The external confining pressure of the matrix core 2 to be tested reaches 40MPa by injecting water through the confining pressure pipe 15 and squeezing the rubber sleeve 14.

[0042] Example 7 The difference between this embodiment and embodiment 4 is that: The simulated formation water had a salinity of 5000 mg / L, and the simulated formation oil had a viscosity of 2 mPa / s.

[0043] Example 8 The difference between this embodiment and embodiment 4 is that: The simulated formation water had a salinity of 50,000 mg / L, and the simulated formation oil had a viscosity of 1 mPa / s.

[0044] Example 9 The difference between this embodiment and embodiment 4 is that: S3, Dynamic seepage of water through fractures: The servo motor push rod 7 is activated to pull the two extraction plates 6 backward a certain distance and ensure that the front end of the extraction plates 6 is in the guide groove 52. The extraction speed is 0.5cm / 5s. The simulated fracture on the prefabricated fracture partition 3 is opened. Then, tap water is injected through the second injection pipe 132 at a water injection speed of 5ml / min to simulate the dynamic seepage process. The simulated formation water and simulated formation oil discharged through the fracture guide pipe 51 are collected.

[0045] Example 10 The difference between this embodiment and embodiment 4 is that: S3, Dynamic seepage of water through fractures: The servo motor push rod 7 is activated to pull the two extraction plates 6 backward a certain distance and ensure that the front end of the extraction plates 6 is in the guide groove 52. The extraction speed is 2cm / 5s. The simulated fracture on the prefabricated fracture partition 3 is opened. Then, tap water is injected through the second injection pipe 132 at a water injection speed of 100ml / min to simulate the dynamic seepage process. The simulated formation water and simulated formation oil discharged through the fracture guide pipe 51 are collected.

Claims

1. A dynamic percolation device that fully simulates the temperature and pressure conditions of a tight oil reservoir, characterized in that, It includes a cylindrical core clamping cylinder (1) with openings at both ends, a sealing cover plate (11) at the front end of the core clamping cylinder (1), an annular sealing ring (12) at the rear end of the core clamping cylinder (1), two semi-cylindrical matrix cores (2) symmetrically arranged inside the core clamping cylinder (1), and a prefabricated fracture partition plate (3) between the two matrix cores (2). Two matrix cores (2) to be tested are respectively fixedly connected at their rear ends with a sealing block (4), and the prefabricated fracture partition (3) is fixedly connected at its rear end with a sealing plate (5). The diameter of the rear end of the sealing block (4) is 1.2 to 1.5 times the diameter of the front end. The size of the rear end of the sealing plate (5) matches the size of the rear end of the sealing block (4). The rear ends of the sealing block (4) and the sealing plate (5) are connected to each other and spliced ​​into a circle. A matrix core liquid guide tube (41) is provided at the end of each of the two sealing blocks (4). The front ends of the two matrix core liquid guide tubes (41) pass through the sealing block (4) and are connected to the rear ends of the two matrix cores (2) to be tested respectively. Several fracture liquid guide tubes (51) are provided at the end of the sealing plate (5). The front ends of the fracture liquid guide tubes (51) pass through the sealing plate (5) and are connected to the prefabricated fracture partition (3). The sealing cover plate (11) has two first injection pipes (131) on both sides. The center of the sealing cover plate (11) is provided with several second injection pipes (132) corresponding to the prefabricated crack partition (3). The two first injection pipes (131) correspond to two matric cores (2) to be tested. A rubber sleeve (14) is provided between the outside of the matric core (2) to be tested and the inner wall of the core clamping cylinder (1). The rubber sleeve (14) simultaneously wraps the front end of the sealing block (4) and the sealing plate (5). A confining pressure pipe (15) is provided at the top of the core clamping cylinder (1), and a confining pressure relief pipe (16) is provided on one side of the core clamping cylinder (1). The prefabricated crack partition (3) has symmetrical grooves (31) on both sides of the middle. The grooves (31) are filled with artificial quartz sandstone slabs with flow guiding capacity. A pull plate (6) is slidably connected to each of the two grooves (31). The rear end of the pull plate (6) passes through the guide groove (52) provided inside the sealing plate (5) and extends out of the inner diameter of the sealing ring (12). The front end of the pull plate (6) is flush with the front end of the prefabricated crack partition (3).

2. The dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir throughout the entire process, as described in claim 1, is characterized in that... The sealing cover plate (11) and sealing ring (12) are detachably connected to the internal threads provided at both ends of the outer surface of the core clamping cylinder (1). After the sealing cover plate (11) is tightened, the first injection pipe (131) and the second injection pipe (132) are just in the designated position. The rear end of the sealing cover plate (11) extends into the interior of the core clamping cylinder (1) and is wrapped by the rubber sleeve (14).

3. The dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir throughout the entire process, as described in claim 1, is characterized in that... The sealing block (4) has several limiting blocks (42) at equal intervals on its side wall. The limiting blocks (42) are connected one-to-one with several limiting slots (17) provided at the rear end of the core clamping cylinder (1). The diameter of the rear end of the sealing block (4) is 1.2 times the diameter of the matrix core (2) to be tested.

4. The dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir throughout the entire process, as described in claim 1, is characterized in that... Three of the fracture fluid guide pipes (51) are provided on each side of the extraction plate (6), and three of the second fluid injection pipes (132) are provided. The two first fluid injection pipes (131) are arranged with one high and one low on the left and right sides, and the two matrix core fluid guide pipes (41) are arranged with one high and one low on the left and right sides. The first fluid injection pipe (131) and the matrix core fluid guide pipe (41) on the same matrix core (2) are arranged with one high and one low in the front and back.

5. The dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir throughout the entire process, as described in claim 1, is characterized in that... Each of the two sealing blocks (4) has a positioning groove (43) on its inner sidewall. A spring positioning plate (44) is provided inside the positioning groove (43). One side of the spring positioning plate (44) abuts against the sidewall of the sealing plate (5) to assist in positioning the sealing plate (5).

6. The dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir throughout the entire process, as described in claim 1, is characterized in that... The two draw plates (6) are driven to slide by an external servo motor push rod (7), and the output shaft of the servo motor push rod (7) is fixedly connected to the end of the draw plate (6).

7. A dynamic percolation method for simulating the temperature and pressure conditions of a tight oil reservoir throughout its entire process, based on the dynamic percolation device for simulating the temperature and pressure conditions of a tight oil reservoir throughout its entire process as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Preparation: The complete full-diameter core samples are processed to the specified size according to the experimental requirements, washed with oil in a core washing machine, and then dried in a 100℃ environment for 48 hours. The porosity and permeability of the matrix core are measured using a full-diameter core porosity-permeability analyzer. The cylindrical core is cut into two semi-cylindrical matrix cores (2) using a high-speed wire cutting machine. The two semi-cylindrical matrix cores (2) are placed on the left and right sides of the core clamping cylinder (1), and then the etched prefabricated fracture partition (3) is placed in the core clamping cylinder (1). The sealing block (4) and sealing plate (5) are used to position the matrix core (2) to be tested and the prefabricated fracture partition (3). The two extraction plates (6) are placed in the groove (31) through the guide groove (52). The servo motor push rod (7) is installed at the rear end of the extraction plate (6). Then the sealing cover plate (11) and sealing ring (12) are installed in sequence. Then the entire device is sealed. Water is injected through the confining pressure pipe (15) to squeeze the rubber sleeve (14) so ​​that the external confining pressure of the matrix core (2) to be tested reaches the confining pressure set in the experiment. The constant temperature box is opened and adjusted to simulate reservoir temperature. S2, Matrix core saturated with crude oil: Simulated formation water is slowly injected through two first injection pipes (131) to completely saturate the two semi-cylindrical matrix cores (2) with simulated formation water. Then, simulated formation oil is slowly injected to completely saturate the two matrix cores (2) to be tested with simulated formation oil. The discharged simulated formation water and simulated formation oil are collected through two matrix core liquid guide pipes (41). S3, Dynamic seepage of water into fractures: The servo motor push rod (7) is turned on to pull the two extraction plates (6) backward a certain distance and ensure that the front end of the extraction plate (6) is in the guide groove (52). The extraction speed is 0.5~2cm / 5s. The simulated fracture on the prefabricated fracture partition (3) is opened. Then, tap water is injected through the second injection pipe (132) at a speed of 5~100ml / min to simulate the dynamic seepage process. The simulated formation water and simulated formation oil discharged through the fracture guide pipe (51) are collected.

8. The dynamic percolation method for simulating the temperature and pressure conditions of a tight oil reservoir throughout its entire process, as described in claim 7, is characterized in that... The upper and lower parts of the prefabricated crack partition (3) in S1 are made of hard alloy, so that the artificial quartz sandstone plate inside the groove (31) of the prefabricated crack partition (3) forms a prefabricated simulated crack with interconnected pores. The width of the prefabricated crack partition (3) at the location of the artificial quartz sandstone plate is 0.5~2cm, and the width of the prefabricated crack partition (3) at other locations is 1~3cm.

9. The dynamic percolation method for simulating the temperature and pressure conditions of a tight oil reservoir throughout its entire process, as described in claim 7, is characterized in that... The simulated formation water in S2 has a salinity of 5000~50000 mg / L, and the simulated formation oil has a viscosity of 1~5 mPa / s.

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