CN115078222B - An imbibition physical simulation experimental device and method considering seam end pressure difference - Google Patents

Abstract

The invention belongs to the technical field of experimental equipment and relates to an imbibition physical simulation experimental device that considers seam end pressure difference, including: a simulation cylinder, three liquid inlets, three liquid discharge ports, a left inner cylinder, a confining pressure sleeve, a right The inner cylinder, the pressurizing component, the first liquid inlet pipe, the second liquid inlet pipe, and the third liquid inlet pipe; three liquid discharge pipes are arranged outside the simulation cylinder and connected to the three liquid discharge ports respectively; the detection component, Set on three drain pipes, it is used to detect changes in liquid pressure inside the three drain pipes. Through the cooperative arrangement of the simulation cylinder, the left inner cylinder, the confining pressure sleeve, the right inner cylinder and the pressurizing assembly, the present invention can pressurize both ends of the rock plate sample and the two ends can be in different pressure states, making the rock plate The sample undergoes imbibition exchange under different pressures exerted by the liquid on the left and right sides, simulating the actual imbibition oil recovery process when the rock plate is in a pressure difference between the crack and the matrix, ensuring the accuracy of the experiment and making it closer to reality. Oil recovery process.

Description

An imbibition physical simulation experimental device and method considering seam end pressure difference

Technical field

The invention belongs to the technical field of experimental equipment, and relates to an imbibition physical simulation experimental device and method that considers seam end pressure difference.

Background technique

With the in-depth development of conventional oil resources around the world, the efficient development and utilization of unconventional oil and gas resources, with tight/shale oil as an important component, has gradually become a hot and difficult topic in research. Accelerating the exploration and development of tight/shale oil has a demonstration effect on the breakthrough of my country's continental unconventional oil and gas resources. Compared with conventional oil reservoirs, the matrix overburden permeability of tight/shale oil reservoirs is generally less than 0.1×10 ^-3 μm ² . At this stage, large-scale volume fracturing technology for horizontal wells is the basic means of industrial development. Unlike conventional oil reservoir matrices, Internal pressure difference displacement oil recovery is different. After this type of reservoir has been transformed by large-scale volume fracturing, the injected water mainly flows along the fractures under the matrix-high permeability fracture dual media system, and it is difficult to form effective displacement in the matrix. The fracture-matrix system The capillary imbibition between the reservoirs is the main mechanism of crude oil movement in the matrix of this type of oil reservoir.

At present, experimental research on the imbibition displacement rules of tight/shale cores mainly focuses on imbibition displacement under normal pressure (i.e., spontaneous imbibition), and does not consider imbibition displacement under the influence of external fluid pressure (i.e., pressure imbibition). For the experimental study of pressure imbibition rules in tight/shale cores, there are several problems: First, the amount of imbibition replacement in conventional core scales is small, and physical simulation experiments are conducted under pressurized conditions. Conventional volume and mass methods It is difficult to achieve accurate measurement using this method; secondly, tight/shale cores have obvious stress-sensitive characteristics under overburden pressure, and whether changes in pore structure will affect imbibition displacement. One of the high-temperature and high-pressure core imbibition experimental devices and methods (Application No. 201810598183. There is a significant pressure difference between the pressure exerted on the fracture surface and the pressure in the matrix core. The above device cannot simulate the imbibition phenomenon when there is a pressure difference between the end face of the fracture core and the core matrix under high pressure.

Contents of the invention

The purpose of the present invention is to provide an imbibition physical simulation experimental device and method that considers the pressure difference at the fracture end to solve the technical problem that the experimental device cannot simulate the imbibition phenomenon when there is a pressure difference between the fracture core end face and the core matrix under high pressure.

In order to achieve the above purpose, the specific technical solution of the present invention is as follows: an imbibition physical simulation experimental device and method that considers the seam end pressure difference:

An imbibition physical simulation experimental device that considers seam end pressure difference, including:

Simulation cylinder has three liquid inlets and three liquid discharge ports on opposite sides of the cylinder;

The left inner cylinder, the confining pressure sleeve and the right inner cylinder are arranged inside the simulation cylinder in sequence from left to right and are opposite to the three liquid inlets and three liquid discharge ports respectively. The left inner cylinder and the right inner cylinder pass through the confining pressure The left inner cylinder and the right inner cylinder are respectively in contact with the inner wall of the simulation cylinder. The inside of the left inner cylinder and the right inner cylinder are connected with the corresponding liquid inlet and drain port respectively. There is a gap between the confining pressure sleeve and the inner wall of the simulation cylinder. Interval, the inside of the confining sleeve is used to place rock slab samples;

The pressurizing component is arranged outside the simulation cylinder and is connected to the three liquid inlets through the first, second and third liquid inlet pipes, respectively, for pressurizing the inside of the left inner cylinder and the confining pressure sleeve. , apply pressure inside the right inner cylinder;

Three drain pipes are arranged outside the simulation cylinder and connected to three drain ports respectively;

The detection component is arranged on the three drain pipes and is used to detect changes in liquid pressure inside the three drain pipes.

The invention is also characterized by:

The pressurizing assembly includes a first advection pump, a second advection pump and a third advection pump. The first advection pump is connected to the liquid inlet near the left inner cylinder through a first liquid inlet pipe, and the second advection pump passes through a second advection pipe. The liquid inlet pipe is connected to the liquid inlet near the confining pressure sleeve, the third advection pump is connected to the liquid inlet near the right inner cylinder through the third liquid inlet pipe, and the first advection pump is provided with a first piston-type intermediate container, the third liquid inlet pipe is provided with a second piston-type intermediate container, and the first liquid inlet pipe, the second liquid inlet pipe, and the third liquid inlet pipe are respectively provided with first valves 10 .

It also includes a thermostat, in which the simulation cylinder, the first piston-type intermediate container, the second piston-type intermediate container, and the detection component are respectively located.

The detection component includes three pressure sensors. The three pressure sensors are respectively installed on three drain pipes. Each drain pipe is equipped with a three-way pipe at the end far away from the simulation tube. The pressure sensor is installed on an interface of the three-way pipe. Another interface of the tee pipe is provided with a second valve.

An embedded information processor is provided outside the thermostatic box, and the embedded information processor is electrically connected to three pressure sensors respectively. A control terminal is provided on one side of the embedded information processor, and the control terminal is electrically connected to the embedded information processor.

The two ends of the simulation tube are open structures, and the two ends of the simulation tube are respectively provided with window fixing tubes. Each window fixing tube is threadedly connected to the inner wall of the simulation tube. Each window fixing tube is provided with a glass window inside. Each window fixing tube A high-definition endoscope is provided outside near the glass window, and the high-definition endoscope is electrically connected to the control terminal.

A rock plate fixed cylinder is provided in the right inner cylinder close to the confining pressure sleeve, and the rock plate fixed cylinder is threadedly connected to the inner wall of the right inner cylinder.

An imbibition physical simulation experimental method considering the seam-end pressure difference, including the following steps:

Step 1. Preparation of rock plate samples: Use the vacuum method to measure the porosity of the rock plate, measure the thickness and diameter of the rock plate, use the soap film method to measure the permeability of the rock plate, screen out the rock plate samples that meet the requirements, and then separate them. The configured simulated imbibition liquid and simulated oil are injected into the upper parts of the piston of the first piston-type intermediate container and the second piston-type intermediate container, and the temperature of the thermostat is set to the simulated temperature;

Step 2: Load the rock plate sample: Open the window fixing tube and the rock plate fixing tube on the right side of the simulation tube in sequence, place the rock plate sample in the confining pressure sleeve, tighten the rock plate fixing tube and the window fixing tube in sequence, and then open For the second advection pump, set the second advection pump to the confining pressure value set by the experiment, keep the pressure stable, and open the first valve on the second liquid inlet pipe and the third valve on the discharge pipe corresponding to the second liquid inlet pipe. Second valve, when kerosene appears at the outlet end of the second drain channel, close the second valve on the drain pipe corresponding to the second liquid inlet pipe, and squeeze the confining sleeve through the pressure of kerosene, so that the confining sleeve is in contact with the rock plate The samples are in close contact, and the rock plate sample is sealed except for both ends;

Step 3: Fill the simulation fluid: Open the first valve on the first liquid inlet pipe and the third liquid inlet pipe in sequence, and the second valve on the discharge pipe corresponding to the first liquid inlet pipe, and the corresponding valve on the third liquid inlet pipe. The second valve on the discharge pipe opens the first advection pump and the third advection pump at the same time, and starts to fill the left inner cylinder and the right inner cylinder with simulated imbibition fluid and simulated oil respectively. When the first liquid inlet pipe 6 corresponds After simulated imbibition liquid appears in the drain pipe, and simulated oil appears at the outlet end of the drain pipe corresponding to the third liquid inlet pipe, close the second valve and the first advection pump and the third advection pump on the two drain pipes;

Step 4, high-pressure imbibition simulation: turn on the first advection pump and the third advection pump, and set them to corresponding constant pressure values. Keep the left and right inner cylinders at different pressures. The rock plate samples are placed on the left and right sides. Osmotic exchange occurs under different pressures exerted by side fluids;

Step 5: Dynamic data collection: Starting from filling the simulation fluid, the embedded information processor collects the pressure values on the three pressure sensors every minute and feeds them back to the control terminal. At the same time, the two high-definition endoscopes collect two glasses in real time. The video information of changes in the rock plate sample in the window is fed back to the control terminal;

Step 6: End of simulation: When the pressure difference between the left inner cylinder and the right inner cylinder is stable, the simulation experiment can be stopped, the experimental device is closed, the simulation liquid is removed, the rock plate is taken out and wrapped in plastic wrap, and the experimental device is cleaned.

The simulated oil in step 1 is one of 3# white oil, 5# white oil, 7# white oil and 10# white oil. The simulated imbibition liquid in step 1 is prepared from one of heavy water, fluorinated liquid and water. .

It also includes step seven, rock plate sample analysis: conduct nuclear magnetic resonance monitoring on the dry rock plate samples before the experiment, the rock plate samples saturated with simulated oil, and the rock plate samples after the simulated imbibition experiment, and analyze the rock plate samples in three time periods. The hydrogen signal amount in the rock plate samples was detected, and the changes in the hydrogen signal amount in the rock plate samples in three time periods were analyzed to determine the amount of imbibition of the rock plate samples under different temperature and pressure conditions.

The imbibition physical simulation experimental device and method of the present invention that considers the seam end pressure difference have the following advantages:

First, through the combination of the simulation cylinder, the left inner cylinder, the confining pressure sleeve, the right inner cylinder and the pressurizing assembly, both ends of the rock plate sample can be pressurized and the two ends can be in different pressure states, making the rock The plate sample undergoes imbibition exchange under different pressures exerted by the liquid on the left and right sides, simulating the actual imbibition oil recovery process when the rock plate is in a pressure difference between the crack and the matrix, ensuring the accuracy of the experiment and making it closer Actual oil production process;

Second, through the setting of the confining sleeve, the confining sleeve can be in close contact with the rock plate sample under the action of force, thereby sealing the rock plate sample except at both ends, ensuring the normal conduct of the experiment and ensuring the accuracy of the experiment. accuracy;

Third, through the setting of a high-definition endoscope, changes in rock plate samples can be monitored during the entire experiment, avoiding uncontrollable factors during the experiment and ensuring the normal conduct of the experiment;

Fourth, this device has a simple structure, reasonable design, and is easy to use and operate. It can simulate a maximum temperature of 120°C, a maximum simulated pressure of 30MPa, and simulate a high-pressure imbibition process with a fracture-matrix pressure difference of 0 to 20MPa.

Description of the drawings

Figure 1 is a schematic diagram of the overall structure of the present invention;

Figure 2 is a schematic diagram of the internal structure of the simulation cylinder in the present invention;

Reference signs:

1. Embedded information processor; 2. Control terminal; 3. First advection pump; 4. Second advection pump; 5. Third advection pump; 6. First liquid inlet pipe; 7. Second liquid inlet pipe ; 8. Third liquid inlet pipe; 9. Discharge pipe; 10. First valve; 11. First piston-type intermediate container; 12. Second piston-type intermediate container; 13. Thermostat; 14. High-definition endoscope ; 15. Pressure sensor; 16. Simulation cylinder; 17. Glass window; 19. Liquid inlet; 20. Second valve; 23. Window fixed cylinder; 24. Drain port; 27. Rock plate fixed cylinder; 28. Left Inner cylinder; 29, confining pressure sleeve; 30, right inner cylinder.

Detailed ways

In order to better understand the purpose, structure and function of the present invention, a further detailed description of the imbibition physical simulation experimental device and method of the present invention taking into account the seam-end pressure difference is given below with reference to the accompanying drawings.

As shown in Figures 1 and 2, the present invention is an imbibition physical simulation experimental device that considers seam end pressure difference, including a simulation cylinder 16. The cylinder body of the simulation cylinder 16 is provided with three liquid inlets 19 and three liquid inlets on opposite sides. There are three liquid discharge ports 24, and three liquid inlets 19 respectively correspond to the positions of the three liquid discharge ports 24. The interior of the simulation cylinder 16 is provided with a left inner cylinder 28, a confining pressure sleeve 29 and a right inner cylinder 30 in sequence from left to right. , the left inner cylinder 28, the confining pressure sleeve 29, and the right inner cylinder 30 are respectively opposite to the positions of three liquid inlets 19 and three liquid discharge ports 24. The left inner cylinder 28 corresponds to one liquid inlet 19 and one liquid discharge port 24. , the confining pressure sleeve 29 corresponds to a liquid inlet 19 and a liquid discharge port 24, the right inner cylinder 30 corresponds to a liquid inlet 19 and a liquid discharge port 24, the left inner cylinder 28 and the right inner cylinder 30 are connected through the confining pressure sleeve 29 , the left inner cylinder 28 and the right inner cylinder 30 are respectively in contact with the inner wall of the simulation cylinder 16 and connected to the inner wall of the simulation cylinder 16 through a sealing ring. The inside of the left inner cylinder 28 and the right inner cylinder 30 are respectively connected with the corresponding liquid inlet 19 and exhaust port. The liquid port 24 is connected, and there is a gap between the confining pressure sleeve 29 and the inner wall of the simulation cylinder 16. The inside of the confining pressure sleeve 29 is used to place the rock plate sample, and the simulation cylinder 16 is provided with a pressurizing component outside, and the pressurizing component passes through the first liquid inlet pipe. 6. The second liquid inlet pipe 7 and the third liquid inlet pipe 8 are connected to the three liquid inlets 19 respectively. The pressurizing components are respectively used to apply pressure to the inside of the left inner cylinder 28, the confining pressure sleeve 29, and the right inner cylinder 30. Pressure, the pressure inside the left inner cylinder 28 and the pressure inside the right inner cylinder 30 are used to exert pressure on both ends of the rock plate sample. After the outer wall of the confining pressure sleeve 29 is pressed, it is in close contact with the internal rock plate sample, and the rock plate sample is In addition to sealing at other positions at both ends to ensure normal operation of the experiment, three drain pipes 9 are provided outside the simulation cylinder 16. The three drain pipes 9 are respectively connected to the three drain ports 24. The three drain pipes 9 are provided with The detection component is used to detect changes in liquid pressure inside the three drain pipes 9 .

The pressurizing assembly includes a first advection pump 3, a second advection pump 4 and a third advection pump 5. The first advection pump 3 is connected to the liquid inlet 19 near the left inner cylinder 28 through the first liquid inlet pipe 6. The second advection pump 4 is connected to the liquid inlet 19 near the confining pressure sleeve 29 through the second liquid inlet pipe 7, and the third advection pump 5 is connected to the liquid inlet 19 near the right inner cylinder 30 through the third liquid inlet pipe 8. connection, the first advection pump 3 is provided with a first piston-type intermediate container 11, the third liquid inlet pipe 8 is provided with a second piston-type intermediate container 12, the first liquid inlet pipe 6, the second liquid inlet pipe 7, and the The three liquid inlet pipes 8 are respectively provided with first valves 10 .

The present invention also includes a thermostatic box 13. The simulation cylinder 16, the first piston-type intermediate container 11, the second piston-type intermediate container 12, and the detection component are respectively located in the thermostatic box 13. The thermostatic box 13 provides stable stability for the realization of the thermostatic box. The temperature control range is: -10℃～160℃.

The detection component includes three pressure sensors 15. The three pressure sensors 15 are respectively arranged on the three drain pipes 9. Each drain pipe 9 is provided with a three-way pipe at the end far away from the simulation tube 16. The pressure sensor 15 is installed on the tee. One interface of the tee pipe and the other interface of the tee pipe are provided with a second valve 20 .

An embedded information processor 1 is provided outside the thermostatic box 13. The embedded information processor 1 is electrically connected to three pressure sensors 15 respectively. A control terminal 2 is provided on one side of the embedded information processor 1. The control terminal 2 is connected to the embedded information processor 1. The processor 1 is electrically connected. The embedded information processor 1 collects the pressure values of the three pressure sensors 15 and then feeds them back to the control terminal 2 .

The two ends of the simulation tube 16 are open structures, and the two ends of the simulation tube 16 are respectively provided with window fixing tubes 23. Each window fixing tube 23 is threadedly connected to the inner wall of the simulation tube 16, and each window fixing tube 23 is provided with a glass window 17 inside. , a high-definition endoscope 14 is provided outside each window fixed barrel 23 close to the glass window 17. The high-definition endoscope 14 is electrically connected to the control terminal 2. The two high-definition endoscopes 14 are used to collect the two glass windows 17 in real time. The video information of changes in the rock plate sample inside is fed back to the control terminal 2. The resolution of the high-definition endoscope 14 is 20 million pixels.

A rock plate fixed cylinder 27 is provided in the right inner cylinder 30 close to the confining pressure sleeve 29. The rock plate fixed cylinder 27 will not block the liquid inlet 19 and the liquid discharge port 24. The rock plate fixed cylinder 27 and the right inner cylinder 30 The inner wall is threaded, and the rock plate fixing cylinder 27 is used to fix one end of the rock plate sample, and the other end of the fixed rock plate sample is against the end of the left inner cylinder 28.

An imbibition physical simulation experimental method considering the seam-end pressure difference, including the following steps:

Step 1. Preparation of rock plate samples: Use the vacuum method to measure the porosity of the rock plate, measure the thickness and diameter of the rock plate, use the soap film method to measure the permeability of the rock plate, screen out the rock plate samples that meet the requirements, and then separate them. The configured simulated imbibition liquid and simulated oil are injected into the piston upper parts of the first piston-type intermediate container 11 and the second piston-type intermediate container 12, and the temperature of the thermostatic box 13 is set to the simulated temperature;

Step two, load the rock plate sample: Open the window fixing tube 23 and the rock plate fixing tube 27 on the right side of the simulation tube 16 in sequence, place the rock plate sample in the confining pressure sleeve 29, and tighten the rock plate fixing tube 27 and the window in sequence. Fix the cylinder 23, then open the second advection pump 4, set the second advection pump 4 to the experimentally set confining pressure value, keep the pressure stable, open the first valve 10 and the second inlet pipe on the second liquid inlet pipe 7 The second valve 20 on the drain pipe 9 corresponding to the liquid pipe 7, when kerosene appears at the outlet end of the second drain channel, closes the second valve 20 on the drain pipe 9 corresponding to the second liquid inlet pipe 7, and passes The pressure of kerosene squeezes the confining pressure sleeve 29 so that the confining pressure sleeve 29 is in close contact with the rock plate sample, and the rock plate sample is sealed except for both ends;

Step 3: Fill the simulated liquid: sequentially open the first valve 10 on the first liquid inlet pipe 6 and the third liquid inlet pipe 8 and the second valve 20 on the discharge pipe 9 corresponding to the first liquid inlet pipe 6. The second valve 20 on the discharge pipe 9 corresponding to the three inlet pipes 8 opens the first advection pump 3 and the third advection pump 5 at the same time, and starts to fill the left inner cylinder 28 and the right inner cylinder 30 with simulated imbibition respectively. liquid and simulated oil. When simulated suction liquid appears in the drain pipe 9 corresponding to the first liquid inlet pipe 6 and simulated oil appears at the outlet end of the drain pipe 9 corresponding to the third liquid inlet pipe 8, close the two drain pipes 9 the second valve 20 and the first advection pump 3 and the third advection pump 5;

Step 4, high-pressure imbibition simulation: turn on the first advection pump 3 and the third advection pump 5, and set them to corresponding constant pressure values, keeping the left inner cylinder 28 and the right inner cylinder 30 at different pressures. The sample undergoes imbibition exchange under different pressures exerted by the liquid on the left and right sides;

Step 5, dynamic data collection: Starting from filling the simulation fluid, the embedded information processor 1 collects the pressure values on the three pressure sensors 15 every minute and feeds them back to the control terminal 2. At the same time, the two high-definition endoscopes 14 real-time Collect the video information of changes in the rock slab samples in the two glass windows 17 and feed it back to the control terminal 2;

Step 6: End of simulation: When the pressure difference between the left inner cylinder 28 and the right inner cylinder 30 is stable, the simulation experiment can be stopped, the experimental device is closed, the simulation liquid is removed, the rock slab is taken out and wrapped in plastic wrap, and the experimental device is cleaned.

Among them, the simulated oil in step one is one of 3# white oil, 5# white oil, 7# white oil and 10# white oil. In the step one, the simulated imbibition liquid is composed of heavy water, fluorinated liquid, and water. A preparation.

It also includes step seven, rock plate sample analysis: conduct nuclear magnetic resonance monitoring on the dry rock plate samples before the experiment, the rock plate samples saturated with simulated oil, and the rock plate samples after the simulated imbibition experiment. The hydrogen signal amount in the rock plate samples was detected, and the changes in the hydrogen signal amount in the rock plate samples in three time periods were analyzed to determine the amount of imbibition of the rock plate samples under different temperature and pressure conditions. Among them, the rock plate samples saturated with simulated oil Simulate oil saturated rock sample absorption for dry rock sample.

Among them, the NMR hydrogen signal amount of the dry sample rock plate = the area of the NMR curve of the dry sample;

The NMR hydrogen signal amount of the saturated simulated oil rock plate = the area of the NMR curve of the saturated simulated oil sample - the area of the NMR curve of the dry sample;

The NMR hydrogen signal of the rock plate after imbibition and drainage = the NMR hydrogen signal of the saturated simulated oil rock plate - the area of the NMR curve of the sample after the imbibition experiment;

The efficiency of imbibition and drainage = the NMR hydrogen signal of the rock slab after imbibition and drainage * 100 / the NMR hydrogen signal of the saturated simulated oil rock slab.

Among them, the maximum simulated temperature is 120°C, the maximum simulated pressure is 30MPa, and the simulated fracture-matrix pressure difference is 0 to 20MPa.

Working principle: When using, first use the vacuum method to measure the porosity of the rock plate, measure the thickness and diameter of the rock plate, use the soap film method to measure the permeability of the rock plate, and inject the configured simulated imbibition liquid and simulated oil respectively. Set the temperature of the thermostatic box 13 to the simulated temperature on the piston upper parts of the first piston-type intermediate container 11 and the second piston-type intermediate container 12, and then open the window fixing cylinder 23 and the rock plate fixing cylinder 27 on the right side of the simulation cylinder 16 in sequence. , place the rock plate sample in the confining pressure sleeve 29, and tighten the rock plate fixing cylinder 27 and the window fixing cylinder 23 in sequence, then open the second advection pump 4, and set the second advection pump 4 to the experimental setting. Pressure value, keep the pressure stable, open the first valve 10 on the second liquid inlet pipe 7 and the second valve 20 on the discharge pipe 9 corresponding to the second liquid inlet pipe 7, when the outlet end of the second liquid discharge channel appears After the kerosene is discharged, close the second valve 20 on the discharge pipe 9 corresponding to the second liquid inlet pipe 7, squeeze the confining pressure sleeve 29 through the pressure of kerosene, so that the confining pressure sleeve 29 is in close contact with the rock plate sample, and the rock plate sample is Remove the other seals at both ends, and then open the first valve 10 on the first liquid inlet pipe 6, the third liquid inlet pipe 8 and the second valve 20 on the discharge pipe 9 corresponding to the first liquid inlet pipe 6. The second valve 20 on the discharge pipe 9 corresponding to the three inlet pipes 8 opens the first advection pump 3 and the third advection pump 5 at the same time, and starts to fill the left inner cylinder 28 and the right inner cylinder 30 with simulated imbibition respectively. liquid and simulated oil. When simulated suction liquid appears in the drain pipe 9 corresponding to the first liquid inlet pipe 6 and simulated oil appears at the outlet end of the drain pipe 9 corresponding to the third liquid inlet pipe 8, close the two drain pipes 9 on the second valve 20 and the first advection pump 3 and the third advection pump 5, and then open the first advection pump 3 and the third advection pump 5, and set them to the corresponding constant pressure value, keeping the left inner cylinder 28 and the right inner cylinder 30 have different pressures. The rock plate sample undergoes imbibition and exchange under the different pressures exerted by the liquids on the left and right sides. Starting from the filling of the simulation fluid, the embedded information processor 1 collects three pressure sensors per minute. 15 and feed it back to the control terminal 2. At the same time, two high-definition endoscopes 14 collect the video information of the rock plate sample changes in the two glass windows 17 in real time and feed it back to the control terminal 2. When the left inner After the pressure difference between the cylinder 28 and the right inner cylinder 30 is stable, the simulation experiment can be stopped, the experimental device is closed, the simulation liquid is removed, the rock slab is taken out and wrapped in plastic wrap, the experimental device is cleaned, and finally the dried rock slab sample before the experiment is , rock plate samples saturated with simulated oil and rock plate samples after simulated imbibition experiments were monitored by nuclear magnetic resonance, the hydrogen content in the rock plate samples in three time periods was detected, and the hydrogen content in the rock plate samples in the three time periods was analyzed. Changes in hydrogen content are used to determine the amount of imbibition of rock plate samples under different temperature and pressure conditions.

The imbibition physical simulation experimental device and method of the present invention that considers the seam end pressure difference have the following advantages:

First, through the combination of the simulation cylinder, the left inner cylinder, the confining pressure sleeve, the right inner cylinder and the pressurizing assembly, both ends of the rock plate sample can be pressurized and the two ends can be in different pressure states, making the rock The plate sample undergoes imbibition exchange under different pressures exerted by the liquid on the left and right sides, simulating the actual imbibition oil recovery process when the rock plate is in a pressure difference between the crack and the matrix, ensuring the accuracy of the experiment and making it closer Actual oil production process;

Second, through the setting of the confining sleeve, the confining sleeve can be in close contact with the rock plate sample under the action of force, thereby sealing the rock plate sample except at both ends, ensuring the normal conduct of the experiment and ensuring the accuracy of the experiment. accuracy;

Third, through the setting of a high-definition endoscope, changes in rock plate samples can be monitored during the entire experiment, avoiding uncontrollable factors during the experiment and ensuring the normal conduct of the experiment;

Fourth, this device has a simple structure, reasonable design, and is easy to use and operate. It can simulate a maximum temperature of 120°C, a maximum simulated pressure of 30MPa, and simulate a high-pressure imbibition process with a fracture-matrix pressure difference of 0 to 20MPa.

It is understood that the present invention has been described through some embodiments. Those skilled in the art know that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, the features and embodiments may be modified to adapt a particular situation and material to the teachings of the invention without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed here, and all embodiments falling within the scope of the claims of the present application are within the scope of protection of the present invention.

Claims (5)

1. Imbibition physical simulation experiment device considering slit end pressure difference is characterized by comprising:

the simulation cylinder (16) is provided with three liquid inlets (19) and three liquid outlets (24) on two opposite sides of the cylinder body respectively;

the device comprises a left inner cylinder (28), a confining pressure sleeve (29) and a right inner cylinder (30), wherein the left inner cylinder (28), the confining pressure sleeve (29) and the right inner cylinder (30) are sequentially arranged inside a simulation cylinder (16) from left to right and are respectively opposite to three liquid inlets (19) and three liquid outlets (24), the left inner cylinder (28) and the right inner cylinder (30) are connected through the confining pressure sleeve (29), the left inner cylinder (28) and the right inner cylinder (30) are respectively contacted with the inner wall of the simulation cylinder (16), the inside of the left inner cylinder (28) and the inside of the right inner cylinder (30) are respectively communicated with the corresponding liquid inlets (19) and the corresponding liquid outlets (24), a space is reserved between the confining pressure sleeve (29) and the inner wall of the simulation cylinder (16), and the inside of the confining pressure sleeve (29) is used for placing rock plate samples;

the pressurizing assembly is arranged outside the simulation cylinder (16), is connected with three liquid inlets (19) through a first liquid inlet pipe (6), a second liquid inlet pipe (7) and a third liquid inlet pipe (8) respectively, and is used for applying pressure to the inside of the left inner cylinder (28), the inside of the confining pressure sleeve (29) and the inside of the right inner cylinder (30) respectively, and keeping different pressures in the left inner cylinder (28) and the inside of the right inner cylinder (30), so that the rock plate sample is subjected to imbibition exchange under the different pressures applied by the liquid at the left side and the right side;

three liquid discharge pipes (9) which are arranged outside the simulation cylinder (16) and are respectively connected with three liquid discharge ports (24);

the detection assembly is arranged on the three liquid discharge pipes (9) and is used for detecting the liquid pressure change in the three liquid discharge pipes (9);

the pressurizing assembly comprises a first advection pump (3), a second advection pump (4) and a third advection pump (5), the first advection pump (3) is connected with a liquid inlet (19) close to a left inner cylinder (28) through a first liquid inlet pipe (6), the second advection pump (4) is connected with a liquid inlet (19) close to a confining pressure sleeve (29) through a second liquid inlet pipe (7), the third advection pump (5) is connected with a liquid inlet (19) close to a right inner cylinder (30) through a third liquid inlet pipe (8), a first piston type intermediate container (11) is arranged on the first advection pump (3), a second piston type intermediate container (12) is arranged on the third liquid inlet pipe (8), a first valve (10) is respectively arranged on the first liquid inlet pipe (6), the second liquid inlet pipe (7) and the third liquid inlet pipe (8), an analog liquid permeation type intermediate container (12) is arranged in the first piston type intermediate container (11);

the device also comprises an incubator (13), wherein the simulation cylinder (16), the first piston type intermediate container (11), the second piston type intermediate container (12) and the detection assembly are respectively positioned in the incubator (13);

the detection assembly comprises three pressure sensors (15), the three pressure sensors (15) are respectively arranged on three liquid discharge pipes (9), a three-way pipe is arranged at the end part, far away from the simulation cylinder (16), of each liquid discharge pipe (9), the pressure sensors (15) are arranged at one interface of the three-way pipe, and a second valve (20) is arranged at the other interface of the three-way pipe.

2. The seepage physical simulation experiment device considering the seam end pressure difference according to claim 1, wherein an embedded information processor (1) is arranged outside the incubator (13), the embedded information processor (1) is respectively and electrically connected with three pressure sensors (15), a control terminal (2) is arranged on one side of the embedded information processor (1), and the control terminal (2) is electrically connected with the embedded information processor (1).

3. The seepage physical simulation experiment device considering the seam end pressure difference according to claim 2, wherein two ends of the simulation cylinder (16) are of an opening structure, window fixing cylinders (23) are respectively arranged at two ends of the simulation cylinder (16), each window fixing cylinder (23) is in threaded connection with the inner wall of the simulation cylinder (16), a glass window (17) is arranged in each window fixing cylinder (23), a high-definition endoscope (14) is arranged at a position, close to the glass window (17), outside each window fixing cylinder (23), and the high-definition endoscope (14) is electrically connected with the control terminal (2).

4. A seepage physical simulation experiment device considering a seam end pressure difference according to claim 3, wherein a rock plate fixing cylinder (27) is arranged in the right inner cylinder (30) at a position close to the confining pressure sleeve (29), and the rock plate fixing cylinder 27 is in threaded connection with the inner wall of the right inner cylinder 30.

5. A seepage physical simulation experiment method considering the pressure difference of a seam end, which adopts the seepage physical simulation experiment device considering the pressure difference of the seam end as claimed in claim 4, and is characterized by comprising the following steps:

step one, preparing a rock plate sample: measuring the porosity of a rock plate by using a vacuumizing method, measuring the thickness and the diameter of the rock plate, measuring the permeability of the rock plate by using a soap film method, screening out a rock plate sample meeting the requirements, then respectively injecting the configured simulated seepage liquid and simulated oil into the upper parts of pistons of a first piston type intermediate container (11) and a second piston type intermediate container (12), and setting the temperature of a constant temperature box (13) to a simulated temperature;

step two, filling a rock plate sample: sequentially opening a window fixing cylinder (23) and a rock plate fixing cylinder (27) on the right side of the simulation cylinder (16), placing a rock plate sample in a surrounding pressure sleeve (29), sequentially screwing the rock plate fixing cylinder (27) and the window fixing cylinder (23), then opening a second parallel flow pump (4), setting the second parallel flow pump (4) to be a set experimental surrounding pressure value, keeping stable pressure, opening a first valve (10) on a second liquid inlet pipe (7) and a second valve (20) on a liquid discharge pipe (9) corresponding to the second liquid inlet pipe (7), closing the second valve (20) on the liquid discharge pipe (9) corresponding to the second liquid inlet pipe (7) after kerosene appears at the outlet end of a second liquid discharge channel, extruding the surrounding pressure sleeve (29) through the pressure of the kerosene, enabling the surrounding pressure sleeve (29) to be in close contact with the rock plate sample, and sealing other positions at two ends of the rock plate sample;

step three, filling injection molding liquid: sequentially opening a first valve (10) on a first liquid inlet pipe (6) and a third liquid inlet pipe (8) and a second valve (20) on a liquid outlet pipe (9) corresponding to the first liquid inlet pipe (6) and a second valve (20) on a liquid outlet pipe (9) corresponding to the third liquid inlet pipe (8), simultaneously opening a first advection pump (3) and a third advection pump (5), starting to fill an injection simulated permeation liquid and simulated oil into a left inner cylinder (28) and a right inner cylinder (30) respectively, and closing the second valves (20) on the two liquid outlet pipes (9) and the first advection pump (3) and the third advection pump (5) after simulated oil appears at the outlet end of the liquid outlet pipe (9) corresponding to the first liquid inlet pipe (6);

step four, high-pressure imbibition simulation: the first advection pump (3) and the third advection pump (5) are opened, the corresponding constant pressure values are set, different pressures are kept in the left inner cylinder (28) and the right inner cylinder (30), and the rock plate sample is subjected to imbibition exchange under different pressures exerted by the liquid at the left side and the right side;

step five, data dynamic acquisition: starting from filling the simulation liquid, the embedded information processor (1) collects pressure values on three pressure sensors (15) every minute and feeds the pressure values back to the control terminal (2), and simultaneously, the two high-definition endoscopes (14) collect video information of rock plate sample changes in the two glass windows (17) in real time and feed the video information back to the control terminal (2);

step six, simulation is ended: after the pressure difference between the left inner cylinder (28) and the right inner cylinder (30) is stable, stopping the simulation experiment, closing the experiment device, removing the simulation liquid, taking out the rock plate, wrapping the rock plate with a preservative film, and cleaning the experiment device;

the simulated oil in the first step is one of 3# white oil, 5# white oil, 7# white oil and 10# white oil, and the simulated seepage liquid in the first step is prepared from one of heavy water, fluoridized liquid and water;

and step seven, rock plate sample analysis: and performing nuclear magnetic resonance monitoring on the dried rock plate sample before the experiment, the rock plate sample saturated with the simulated oil and the rock plate sample simulated after the imbibition experiment, detecting hydrogen signal quantity in the rock plate sample in three time periods, analyzing the hydrogen signal quantity change in the rock plate sample in three time periods, and determining imbibition quantity of the rock plate sample under different temperature and pressure conditions.