A spontaneous imbibition experiment measuring device for accurately simulating reservoirs and field development conditions

Abstract

The application discloses a spontaneous imbibition experiment measuring device for accurately simulating a reservoir and field development conditions. The spontaneous imbibition experiment measuring device comprises a high-pressure imbibition core holder, a conversion device of a crude oil saturation and imbibition experiment assembly, a crude oil saturation assembly and a core imbibition assembly. A confining pressure system in the high-pressure imbibition core holder can adjust the core confining pressure in the imbibition experiment process, simulates the ground stress condition of the reservoir, and makes the physical simulation experiment more representative. The conversion device of the crude oil saturation and imbibition experiment assembly can saturate the core with experimental oil containing dissolved gas under the reservoir condition, then carry out the imbibition experiment, ensures that the experimental simulation oil is identical with the crude oil in the reservoir in physical properties, and improves the accuracy of the imbibition experiment result. The imbibition experiment assembly can adjust the imbibition pressure of the core end face in the imbibition experiment, and truly reflects the actual pressure in the field soaking development.

Description

TECHNICAL FIELD

[0001] The present application relates to a spontaneous imbibition experiment measuring device which can accurately simulate reservoir and field development conditions, and belongs to the technical field of oil reservoir development. BACKGROUND

[0002] Low-permeability oil and gas resources are abundant in China and widely distributed. In the middle and late stages of oilfield development, tapping the potential of low-permeability reservoirs is an important part of increasing and stabilizing oil production. Due to the small pore throat, strong heterogeneity and low seepage capacity of low-permeability reservoirs, they face difficulties such as poor injection capacity and low oil recovery efficiency. In contrast, the oil displacement method of spontaneous imbibition in low-permeability reservoirs has the characteristics of strong efficiency and has attracted much attention in recent years. Therefore, it is necessary to provide a device that can carry out imbibition experiments under reservoir conditions, so as to accurately reflect the effect of spontaneous imbibition in low-permeability reservoirs on enhanced oil recovery.

[0003] At present, the imbibition experiment in the laboratory mainly uses Amott imbibition bottles. The measurement principle of the imbibition device is as follows: the core saturated with crude oil is soaked in an imbibition bottle containing imbibition liquid, the imbibition liquid displaces the crude oil from the pores of the core, and under the action of buoyancy, the oil droplets float to the scale tube at the top end of the imbibition bottle, and the imbibition recovery rate is obtained according to the scale of the scale tube. The existing high-temperature and high-pressure imbibition bottle is made of metal material instead of the original glass material Amott imbibition bottle, so that it has the ability of heat conduction and pressure resistance, and can carry out imbibition experiments under high temperature and high pressure conditions. The above method has the following defects: due to the limitation of the design of Amott imbibition bottle, before the imbibition experiment starts, the experimental core is first saturated with a core saturation device to saturate the experimental oil, and then put into the imbibition bottle to carry out the imbibition experiment, which leads to the fact that the experimental oil can only use simulated dead oil without dissolved gas for the experiment, and the difference between the properties of the crude oil and the actual reservoir crude oil containing dissolved gas is large, which will affect the results of the imbibition experiment. High-pressure imbibition experiment is achieved by increasing the pressure of the imbibition liquid in the high-pressure imbibition bottle. Since the core is completely soaked in the imbibition liquid, the pressure on each surface of the core in contact with the imbibition liquid is the same, but the actual reservoir has different stresses around the core, and the current high-pressure imbibition experiment device cannot solve this problem, resulting in errors in the imbibition experiment. Therefore, it is necessary to provide a spontaneous imbibition experiment measuring device which can accurately simulate reservoir and field development conditions. SUMMARY

[0004] The present application aims to provide a new self-spontaneous imbibition experimental measuring device which can accurately simulate the reservoir and field development conditions; the device can complete the core saturation experiment of the crude oil containing dissolved gas under the reservoir conditions, and then carry out the imbibition experiment, thereby ensuring the same physical properties of the experimental simulation oil and the reservoir crude oil; meanwhile, the experimental device can adjust the confining pressure of the core and the pressure of the imbibition experiment, so that the experimental conditions can truly reflect the reservoir and field development conditions, and the accuracy of the imbibition experimental results is ensured.

[0005] The self-spontaneous imbibition experimental measuring device provided by the present application comprises a high-pressure imbibition core holder, a conversion device of a crude oil saturation and imbibition experimental assembly, a crude oil saturation assembly and a core imbibition assembly.

[0006] The high-pressure imbibition core holder comprises a shell and a sleeve; the sleeve is arranged in the shell I, and the ring cavity formed by the shell and the sleeve serves as a confining pressure cavity; a confining pressure liquid inlet and a confining pressure liquid outlet are arranged on the side wall of the shell I and are connected with a confining pressure control system; and the sleeve is used for placing a core.

[0007] The conversion device of the crude oil saturation and imbibition experimental assembly comprises a shell II and a piston I; one end of the shell II is connected with the high-pressure imbibition core holder, the shell II is sequentially matched with the shell I and the sleeve; the other end of the shell II is matched with the crude oil saturation assembly or the core imbibition assembly; a cavity I and at least one imbibition liquid / experimental oil flow channel which is communicated with the cavity I are arranged in the shell II; one end of the imbibition liquid / experimental oil flow channel is communicated with the cavity of the crude oil saturation assembly or the core imbibition assembly, and the other end extends into the sleeve and is located above the core; the piston I is arranged in the cavity I, and the opening and closing of the imbibition liquid / experimental oil flow channel are controlled by the movement of the piston I; the cavity I is connected with a pressure control system connection I through a hydraulic oil injection pipeline I, and is used for applying hydraulic pressure to the piston I.

[0008] The crude oil saturation assembly comprises a shell III and a piston II; the shell III is connected with the shell II, and the imbibition liquid / experimental oil flow channel is communicated with a cavity II formed by the shell III; the piston II is arranged in the cavity II, and the cavity II is divided into a hydraulic oil cavity and an experimental simulation oil cavity; the hydraulic oil cavity is connected with a pressure control system connection II through a hydraulic oil injection pipeline II, and is used for applying hydraulic pressure to the piston II; and the experimental simulation oil cavity is connected with an intermediate container I through a crude oil injection pipeline.

[0009] The core imbibition assembly comprises a shell IV; the shell IV is connected with the shell II, and the imbibition liquid / experimental oil flow channel is communicated with a cavity III formed by the shell IV; the shell IV is connected with an intermediate container II through an imbibition liquid injection pipeline; and a capillary tube extends from the shell IV.

[0010] The self-spontaneous imbibition experiment measuring device, two ends of the shell are provided with ports, respectively sealed by the upper end and the lower end;

[0011] The upper port is threadedly matched with the shell I and the shell II, and matched with a rubber ring to ensure the sealing property;

[0012] The material of the shell I is stainless steel;

[0013] The material of the sleeve is rubber.

[0014] The shell II is threadedly matched with the shell III and the shell IV, and matched with a rubber ring;

[0015] The material of the shell II is stainless steel;

[0016] The imbibition liquid / experiment oil flow channel is arranged along the axial direction of the shell II.

[0017] The shell II is further provided with an imbibition liquid / experiment oil flow bypass connected with the cavity I, and the other end of the imbibition liquid / experiment oil flow bypass is communicated with the cavity of the crude oil saturation assembly or the core imbibition assembly;

[0018] The diameter of the imbibition liquid / experiment oil flow bypass is smaller than that of the imbibition liquid / experiment oil flow channel.

[0019] The shell II is further provided with an imbibition liquid / experiment oil flow bypass connected with the cavity I, and the other end of the imbibition liquid / experiment oil flow bypass is communicated with the cavity of the crude oil saturation assembly or the core imbibition assembly;

[0020] The material of the shell III is stainless steel.

[0021] The cavity III is a conical cavity.

[0022] The crude oil injection pipeline and the imbibition liquid injection pipeline are both provided with switches.

[0023] The intermediate container I and the intermediate container II are both connected with ISCO pumps, used for providing pressure for injecting crude oil or imbibition liquid.

[0024] The application provides a spontaneous imbibition experiment measuring device for accurately simulating reservoirs and field development conditions, which can adjust the core confining pressure in the imbibition experiment process through a confining pressure system, simulates the ground stress conditions of the reservoirs, and makes the physical simulation experiment more representative; a crude oil saturation and imbibition experiment conversion device, which can saturate the core with experimental oil containing dissolved gas under the reservoir conditions, carries out the imbibition experiment, ensures that the experimental simulation oil is the same as the crude oil in the reservoir in physical properties, and improves the accuracy of the imbibition experiment results; and the imbibition pressure of the core end face in the imbibition experiment component can be adjusted, and the actual pressure of the field soak development is truly reflected. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a structural schematic view of the spontaneous imbibition experiment measuring device for accurately simulating reservoirs and field development conditions of the application;

[0026] The various signs in the drawing are as follows:

[0027] 1 shell, 2 sleeve, 3 confining pressure liquid inlet, 4 confining pressure liquid outlet, 5 confining pressure control system, 6 core, 7 shell, 8 piston, 9 sealing ring, 10 cavity, 11 hydraulic oil inlet, 12 hydraulic oil injection pipeline, 13 pressure control system, 14 and 15 imbibition liquid / experimental oil inlet, 16 and 17 imbibition liquid / experimental oil flow channel, 18 sealing ring, 19 crude oil collection cavity, 25 shell, 26 cavity, 27 imbibition liquid injection inlet, 28 imbibition liquid injection pipeline, 29 switch, 30 capillary scale tube, 31 intermediate container, 32 ISCO pump, 33 end, 38 temperature control system.

[0028] Figure 2 It is a structural schematic view of the crude oil saturation and imbibition experiment conversion device in the spontaneous imbibition experiment measuring device for accurately simulating reservoirs and field development conditions of the application;

[0029] The various signs in the drawing are as follows:

[0030] 7 shell, 8 piston, 9 sealing ring, 10 cavity, 11 hydraulic oil inlet, 12 hydraulic oil injection pipeline, 13 pressure control system, 14 and 15 imbibition liquid / experimental oil inlet, 16 and 17 imbibition liquid / experimental oil flow channel, 18 sealing ring, 19 crude oil collection cavity.

[0031] Figure 3 It is a structural schematic view of the crude oil saturation component in the spontaneous imbibition experiment measuring device for accurately simulating reservoirs and field development conditions of the application;

[0032] The various signs in the drawing are as follows:

[0033] 20 shell, 21 cavity, 22 crude oil injection pipeline, 23 pressure control system 2, 24 hydraulic oil injection inlet, 39 piston, 34 sealing ring, 35 crude oil injection inlet, 36 crude oil injection pipeline, 37 switch.

[0034] Figure 4 This is a schematic diagram of the core permeation component in the spontaneous permeation experimental measurement device of the present invention, which accurately simulates reservoir and field development conditions.

[0035] The markings in the diagram are as follows:

[0036] 25 Housing, 26 Cavity, 27 Absorbent Inlet, 28 Absorbent Inlet Line, 29 Switch, 30 Capillary Scale Tube. Detailed Implementation

[0037] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0038] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0039] like Figure 1 As shown, this invention provides a spontaneous percolation experimental measurement device that can accurately simulate reservoir and on-site development conditions, and is used for percolation experiments. The entire device includes: a shell 1, which has openings at both ends and end caps 33 installed at the openings; a confining pressure fluid inlet 3 and a confining pressure fluid outlet 4 are provided on the outer wall of the shell, and the confining pressure fluid inlet 3 and the confining pressure fluid outlet 4 are connected to a confining pressure control system 5; a sleeve 2, which is fixed on the front and rear end caps 33, and an experimental core 6 is placed inside the sleeve; a shell 7 is connected to the front end cap 33; a hydraulic oil inlet 11 is provided on the outer wall of the shell 7, and the hydraulic oil inlet 11 is connected to a hydraulic oil injection line 12; the hydraulic oil injection line 12 is connected to a pressure control system 13; the rear end of the shell 7 is connected to a shell 20 or a shell 25; the outer walls of the shell 20 and the shell 25 are respectively provided with a crude oil injection port 24 and a permeate injection port 27; the crude oil injection port 24 and the permeate injection port 27 are connected to an intermediate container 31 through a crude oil injection line 22 and a permeate injection line 28; the intermediate container 31 is connected to an ISCO pump 32.

[0040] Special requirements reference Figure 1The core holder shell 1 is made of stainless steel, and the two ends are open for installing the end head 33. The sealed cavity formed by the shell 1 and the end head 33 is used to contain the confining pressure fluid. Because the confining pressure fluid needs to be injected into the shell 1, the shell 1 and the end head 33 need to be sealed and connected. The shell 1 and the end head 33 are sealed and connected by threads. The shell 1 is provided with internal threads, and the end head 33 is provided with external threads. The sleeve 2 is made of rubber and can shrink after being subjected to the pressure of the confining pressure fluid, so as to be in close contact with the internal core and transmit the confining pressure to the core. The shell 7 and the end head 33 are sealed and connected by threads. The shell 1 is provided with external threads, and the end head 33 is provided with internal threads. The front end of the shell 7 is inserted into the sleeve 2. In order to ensure the sealing of the front end of the shell 7 and the sleeve, the shell is provided with a rubber ring 18 at the front end. The rear end of the shell 7 is connected with the shell 20 or the shell 25. The experiment is a high-pressure experiment, so the shell 7 and the shell 20 or the shell 25 are sealed and connected by threads when they are connected. The rear end of the shell 7 is provided with external threads, and the shell 20 and the shell 25 are provided with internal threads. The ISCO pump 32 is a precision control pump with constant pressure and constant flow modes, which provides pressure for the experiment.

[0041] The specific description is as follows Figure 1The sleeve 2 is sealed in the housing 1 by the connection of the sleeve 2, the end 33 of the front and back ends and the housing 7, the core 6 is sealed in the sleeve, and the confining pressure fluid is sealed in the cavity of the housing. The confining pressure fluid is injected into the housing through the confining pressure injection port 4, and the confining pressure is controlled through the confining pressure control system. The sleeve 2 will transmit the confining pressure so that the core is subjected to different pressures. In the saturated core experiment stage, the housing 7 is connected with the housing 20, the switch 23 is connected with the intermediate container 31, and the intermediate container is connected with the ISCO pump 32. The housing 7 is connected with the pressure control system 13 through the hydraulic pipeline 12, and the pressure control system is set to the experimental pressure (higher than the saturated oil pressure). At this time, the piston 8 is at the left end of the cavity 10 to block the imbibition fluid / experimental oil flow channel 16, 17, so that the cavity 21 is separated from the core 6. The pressure control system 23 is opened to connect the cavity 21 with the intermediate container 31, and the intermediate container 31 is pressurized through the ISCO pump 32 to transfer the oil in the intermediate container 31 to the cavity 21. The pressure is controlled through the ISCO pump 32 during the whole process to ensure that the saturated pressure of the oil is higher than the oil. After the cavity 21 is filled with oil, the pressure of the oil in the cavity 21 is controlled through the ISCO pump 32 to gradually reach the experimental pressure. The oil pressure in the channel 16 is higher than the hydraulic oil pressure in the cavity 10, the piston 8 is pushed to the right end of the cavity 10, the imbibition fluid / experimental oil flow channel 16, 17 is formed, the cavity 21 is connected with the core 6, and the oil in the cavity 21 can flow into the core 6. The pressure control system 23 is closed, and the oil gradually flows into the core 6 to complete the core saturation. After the oil saturation is completed, the pressure control system 23 is opened, the remaining oil flows out from the oil injection pipeline 22, the oil pressure in the imbibition fluid / experimental oil flow channel 16 is lower than the experimental pressure, the piston 8 moves to the left end of the cavity 10, the imbibition fluid / experimental oil flow channel 16, 17 is blocked, and the oil pressure in the core 6 is maintained at the experimental pressure, which is higher than the oil saturation pressure, so as to avoid the oil from being degassed into dead oil.

[0042] In the high pressure imbibition experiment stage, the crude oil saturation assembly is taken off from the shell 7, the core imbibition assembly is installed, the shell 25 is connected with the shell 7, the switch 29 is communicated with the intermediate container 31, the intermediate container 31 is internally provided with imbibition liquid, the intermediate container is pressurized by the ISCO pump 32, and the imbibition liquid will flow into the cavity 26. After the cavity 26 is filled with the imbibition liquid, the cavity 26 is pressurized to the experimental pressure by the ISCO pump 32, and the switch 29 is closed. When the pressure of the cavity 26 reaches the experimental pressure, the pressure of the imbibition liquid in the imbibition liquid / experimental oil flow channel 16 is slightly higher than the pressure of the hydraulic oil in the cavity 10, the piston 8 is pushed to the right end of the cavity 10, the imbibition liquid / experimental oil flow channel 16, 17 forms a passage, the cavity 26 is communicated with the core 6, the imbibition liquid in the cavity 26 can flow into the core 6 and interact with the end face of the core 6, and the oil droplets produced by the core will be captured by the crude oil collector cavity 19. The tapered crude oil collector cavity 19 ensures that all oil droplets can enter the imbibition liquid / experimental oil flow channel 17 through the imbibition liquid / experimental oil flow channel 17, and the tapered cavity 26 can ensure that all oil droplets enter the capillary scale tube 30, the imbibition oil volume is read through the capillary scale tube 30, and the imbibition recovery rate is obtained.

[0043] In Figure 2 the present embodiment, the crude oil saturation and imbibition experiment conversion device is used for conversion of the crude oil saturation experiment and the imbibition experiment. The whole device comprises: a shell 7, the shell 7 is connected with an end head 33 at the front end, and the rear end of the shell 7 is connected with a shell 20 or a shell 25; the shell 7 is internally provided with a cavity 10 for placing a piston 8, and the piston 8 is provided with a sealing ring; the outer wall of the shell 7 is provided with a hydraulic oil inlet 11, the hydraulic oil inlet 11 is connected with a hydraulic oil injection pipeline 12; the oil injection pipeline 12 is connected with a pressure control system 13; the upper end of the shell 7 is provided with imbibition liquid / experimental oil inlets 14, 15, the imbibition liquid / experimental oil inlets 14, 15 are connected with cavities 21 and 26; the lower end of the shell 7 is provided with a crude oil collector cavity 19, the crude oil collector cavity 19 is connected with the upper end face of a core 6; the shell 7 is internally provided with imbibition liquid / experimental oil flow channels 16, 17, which are connected with the cavities 21, 26 and the core 6.

[0044] Special requirements refer to Figure 2 , the shell 7 of the crude oil saturation and imbibition experiment conversion device is made of stainless steel, the piston 8 is internally placed, and the experiment is carried out under high pressure conditions. In order to ensure the sealing performance of the piston 8 and the cavity 10, the piston 8 is provided with a sealing ring 9; the lower end of the shell 7 is inserted into a sleeve to ensure the sealing performance, and the sealing ring 18 is arranged at the lower end of the shell 7; the shell 7 is connected with the end head 33 and the shell 20 or the shell 25 respectively, and the threaded connection is adopted to ensure the sealing performance; the crude oil collector cavity 19 is designed in a tapered shape to ensure that all oil droplets can enter the imbibition liquid / experimental oil flow channel 17; the diameter of the imbibition liquid / experimental oil flow channel 17 which is internally arranged in the shell is wider than that of the imbibition liquid / experimental oil flow channel 16.

[0045] The specific description is asFigure 2 , the casing 7 is connected with the end 33 and the casing 20 or the casing 26 through threads, the cavity 10 is filled with hydraulic oil through a hydraulic oil injection pipeline, the piston 8 is pushed to the left end of the cavity 10, the pressure of the pressure control system 13 is gradually increased to the experimental pressure, the piston 8 blocks the imbibition liquid / experimental oil flow channels 16 and 17, when the liquid pressure in the imbibition liquid / experimental oil flow channel 16 is the experimental pressure, the piston 8 moves to the right end of the cavity 10, and the imbibition liquid / experimental oil flow channels 16 and 17 are open, and in the imbibition experiment stage, the oil drops produced by the core enter the capillary scale tube 30 through the crude oil collection cavity 19 and the imbibition liquid / experimental oil flow channel 17.

[0046] In Figure 3 , the embodiment provides a crude oil saturation assembly for simulating oil containing dissolved gas before core saturation of reservoir conditions in an imbibition experiment. The whole device comprises a casing 20, a cavity 21 arranged in the casing 20, a piston 39 arranged in the cavity 21, and a rubber ring of the piston 39; an oil injection inlet 35 is arranged on the outer wall of the casing 20, the oil injection inlet 35 is connected with an intermediate container 31 through an injection pipeline 36, and the intermediate container 31 is connected with an ISCO pump 32. A hydraulic oil injection inlet 24 is arranged on the upper end of the casing 20, the hydraulic oil injection inlet 24 is connected with a hydraulic oil injection pipeline 22, and the hydraulic oil injection pipeline 22 is connected with a pressure control system 23.

[0047] Special requirements refer to Figure 3 The casing 20 of the crude oil saturation assembly is made of stainless steel, and the piston 39 is arranged in the casing 20. The piston 39 divides the cavity 21 into an upper cavity and a lower cavity, the upper cavity is used for containing hydraulic oil and maintaining experimental pressure, and the lower cavity is used for containing experimental simulation oil. The experiment is carried out under high pressure conditions, the sealing performance of the piston and the inner wall of the casing 20 is ensured, and the piston 39 is provided with a rubber ring 34. The casing 20 is connected with the casing 7, screw thread connection is adopted to ensure the sealing performance, and threads are arranged in the casing 20. The pressure control system 23 has constant pressure and cross-flow modes, and controls the pressure in the experimental process.

[0048] The specific description is as follows Figure 3, the shell 20 is connected with the shell 7 through thread, the hydraulic oil is filled in the cavity 21 through pipeline 22, the piston 39 is moved to the bottom end of the cavity 21, the pressure is adjusted to the saturation pressure of experimental simulation oil through pressure control system;Open switch 37, crude oil injection inlet 35 injects pipeline 36 middle container 31 and ISCO pump to form a passage, experimental simulation oil is injected into the cavity 21 at the lower end of the piston 39 through the cross-flow mode of ISCO pump, this stage guarantees that the pressure of control pressure system is the saturation pressure of experimental simulation oil, and it is guaranteed that experimental oil will not degas during oil guiding process;When experimental crude oil completely fills the cavity 21, switch 37 is closed;The pressure of pressure control system 23 is gradually increased, and reaches experimental pressure, and the pressure is transmitted to the piston 39 by the hydraulic oil, and the piston 39 moves downward and pushes experimental simulation oil in the lower part of the cavity 21 into the core.

[0049] In Figure 4 , the core imbibition assembly provided by the embodiment is used to carry out high-pressure imbibition experiment.The whole device comprises a shell 25, a conical cavity 26 arranged in the shell, the cavity 26 being connected with a graduated tube 30;The shell 26 is provided with an imbibition liquid injection inlet 27 at the upper end, the imbibition liquid injection inlet 27 being connected with a middle container 31 through an injection pipeline 28, and the middle container 31 being connected with an ISCO pump 32.

[0050] Special requirements refer to Figure 4 , the shell 26 of the crude oil saturation assembly is made of stainless steel, the shell 26 is connected with the shell 7, thread connection is used to ensure sealing, and thread is arranged in the shell 26;The cavity 26 is designed as a conical shape, so that oil drops can enter the capillary graduated tube 30 completely;The capillary graduated tube 30 is made of sapphire glass and has high-pressure resistance, and the graduation accuracy is 0.01ml, so that the accuracy of the volume of crude oil can be ensured.

[0051] The specific description is as follows Figure 4 , the shell 26 is connected with the shell 7 through thread, switch 29 is opened, the imbibition liquid injection inlet 27, the injection pipeline 28, the middle container 31 and the ISCO pump 32 are connected to form a passage, the ISCO pump 32 is controlled to inject the imbibition liquid in the middle container into the cavity 26, the pressure in the cavity 26 is gradually increased to reach experimental pressure, and switch 29 is closed, and the imbibition experiment is started.

[0052] When the spontaneous imbibition experiment measuring device is applied, the following steps can be performed:

[0053] 1, experimental instrument installation

[0054] After the sleeve 2 is fixed on the end head 33, the sleeve 2 is installed in the core holder, the core 6 is placed into the sleeve 2, and it is guaranteed that the bottom end of the core 6 only sticks to the lower end head 33.Petroleum jelly is applied to the bottom end of the adapter device, the adapter device is inserted into the sleeve 2 and sticks to the upper end surface of the core 6, and the threads of the adapter device and the upper end head are twisted to ensure sealing.

[0055] 2. Set the confining pressure of the core

[0056] Set the confining pressure according to the reservoir stress condition. Inject confining fluid into the housing 1, control the confining pressure using the confining pressure control system 5, and maintain the pressure required for the experiment. The confining fluid pressure in the housing 1 acts on the sleeve 2, which is compressed and transmits the pressure to the experimental core 6, thus simulating the stress condition of the core in the reservoir condition.

[0057] 3. Core saturation experiment

[0058] Connect the crude oil saturation assembly to the switching device, and tighten the threads of the switching device and the crude oil saturation assembly to ensure the sealing. Increase the pressure of the piston 8 in the switching device to the experimental pressure by the pressure control system 13, so that the piston 8 is at the leftmost end of the cavity. Increase the pressure of the piston 39 in the crude oil saturation assembly to the crude oil saturation pressure by the pressure control system 23, so that the piston 39 is at the bottom end of the cavity 21. Open the switch of the crude oil saturation assembly, and connect the crude oil saturation assembly to the intermediate container 31 and the ISCO pump 32, set the ISCO pump 32 to cross flow, slowly inject the experimental simulation oil in the intermediate container 31 into the crude oil saturation device, and then close the switch 37. Increase the pressure of the crude oil in the crude oil saturation assembly to the experimental pressure by the pressure control system 23, at this time the crude oil enters the core 6 through the switching device, and the experimental pressure is maintained for one month to ensure that the pores in the core are completely saturated with crude oil and aging, and the core saturation experiment is completed. Reduce the pressure of the crude oil saturation assembly to the experimental pressure by the pressure control system 23, at this time the piston 39 in the switching device blocks the connection between the crude oil saturation assembly and the core 6, ensuring that the saturated oil in the core will not degas, and then gradually reduce the pressure in the crude oil saturation assembly to atmospheric pressure, and remove the crude oil saturation assembly.

[0059] 4. Core imbibition experiment

[0060] Connect the core imbibition assembly to the switching device, and tighten the threads of the switching device and the core imbibition assembly to ensure the sealing. Connect the core imbibition assembly to the intermediate container 31 and the ISCO pump 32, open the switch 29 to connect them, inject the imbibition fluid into the core imbibition assembly through the ISCO pump 32, and close the switch 29 after setting the pressure of the ISCO pump 32 to make the imbibition fluid pressure reach the experimental pressure. After the imbibition fluid pressure reaches the experimental pressure, the imbibition fluid interacts with the core after contacting the core through the switching device, and the crude oil is expelled from the core under the imbibition effect, and the oil droplets enter the capillary scale tube 30 along the channel in the switching device. Read the volume of the crude oil in the capillary scale tube 30 every 6 hours, calculate the oil recovery, and end the experiment until the volume of the crude oil in the capillary scale tube 30 no longer changes, and obtain the total oil recovery during the imbibition process.

[0061] The spontaneous imbibition experimental measuring device provided by the application can accurately simulate reservoir and field development conditions.

[0062] 1. Accuracy, according to the reservoir stress conditions, the confining pressure can be applied to the core, and the imbibition pressure can be adjusted according to the field development pressure, the experiment can accurately simulate the actual situation of the reservoir and the field development, and the experimental result is accurate.

[0063] 2. Through the crude oil saturation and imbibition conversion device, after the experiment of the crude oil containing dissolved gas under the core saturation reservoir condition is completed, the imbibition experiment can be carried out, the physical properties of the experimental simulation oil and the reservoir crude oil are ensured to be the same, and the accuracy of the experimental result is further improved.

[0064] 3. The tapered design of the crude oil collecting cavity and the vertical channel in the adapter device ensure that all oil droplets can enter the graduated tube during the imbibition process, and the precision of the imbibition experiment is ensured.

[0065] 4. The piston in the adapter device realizes the on-off of the core and the upper experimental assembly by controlling the experimental pressure, and ensures the conversion of the crude oil saturation experiment and the imbibition experiment under the experimental pressure.

[0066] 5. The equipment is convenient to install and maintain, the conversion of the crude oil saturation experiment and the imbibition experiment can be completed only by replacing the upper experimental equipment, and it is convenient for the experimental personnel to use.

Claims

1. A spontaneous imbibition experimental measurement device, comprising a high-pressure imbibition core holder, a conversion device of a crude oil saturation and imbibition experimental assembly, a crude oil saturation assembly and a core imbibition assembly; characterized in that: the high-pressure imbibition core holder comprises a shell I and a sleeve; the sleeve is arranged in the shell I, and the ring cavity formed by the two is used as a confining pressure cavity; a confining pressure liquid inlet and a confining pressure liquid outlet are arranged on the side wall of the shell I and are connected with a confining pressure control system; the sleeve is used for placing a core; the conversion device of the crude oil saturation and imbibition experimental assembly comprises a shell II and a piston I; one end of the shell II is connected with the high-pressure imbibition core holder, and the shell II is matched with the shell I and the sleeve in sequence; the other end of the shell II is matched with the crude oil saturation assembly or the core imbibition assembly; a cavity I and at least one imbibition liquid / experimental oil flow channel communicating with the cavity I are arranged in the shell II, one end of the imbibition liquid / experimental oil flow channel communicates with the cavity of the crude oil saturation assembly or the core imbibition assembly, and the other end extends into the sleeve and is located above the core; the piston I is arranged in the cavity I, and the opening and closing of the imbibition liquid / experimental oil flow channel are controlled by the movement of the piston I; the cavity I is connected with a pressure control system connection I through a hydraulic oil injection pipeline I, and is used for applying hydraulic pressure to the piston I; the crude oil saturation assembly comprises a shell III and a piston II; the shell III is connected with the shell II, and the imbibition liquid / experimental oil flow channel communicates with a cavity II formed by the shell III; the piston II is arranged in the cavity II, and the cavity II is divided into a hydraulic oil cavity and an experimental simulation oil cavity; the hydraulic oil cavity is connected with a pressure control system connection II through a hydraulic oil injection pipeline II, and is used for applying hydraulic pressure to the piston II; the experimental simulation oil cavity is connected with an intermediate container I through a crude oil injection pipeline; the core imbibition assembly comprises a shell IV; the shell IV is connected with the shell II, and the imbibition liquid / experimental oil flow channel communicates with a cavity III formed by the shell IV; the shell IV is connected with an intermediate container II through an imbibition liquid injection pipeline; a capillary tube extends from the shell IV.

2. The spontaneous imbibition experimental measurement apparatus according to claim 1, characterized by: both ends of the shell I are provided with ports, and are sealed by an upper end head and a lower end head respectively; the upper end head is threadedly matched with the shell I and the shell II, and is matched with a rubber ring; the material of the shell I is stainless steel; the material of the sleeve is rubber.

3. The spontaneous imbibition experimental measurement apparatus according to claim 1 or 2, characterized by: the shell II is threadedly matched with the shell III and the shell IV, and is matched with a rubber ring; the material of the shell II is stainless steel; the imbibition liquid / experimental oil flow channel is arranged in the axial direction of the shell II.

4. The spontaneous imbibition experimental measurement apparatus according to claim 1 or 2, characterized by: the shell II is further provided with an imbibition liquid / experimental oil flow bypass connected with the cavity I, and the other end of the imbibition liquid / experimental oil flow bypass communicates with the cavity of the crude oil saturation assembly or the core imbibition assembly; the diameter of the imbibition liquid / experimental oil flow bypass is smaller than that of the imbibition liquid / experimental oil flow channel.

5. The spontaneous imbibition experimental measurement apparatus according to claim 1 or 2, characterized by: one end of the shell II forms a tapered collection cavity and is located above the core.

6. The spontaneous imbibition experimental measurement apparatus according to claim 1 or 2, characterized by: the material of the shell III is stainless steel.

7. The spontaneous imbibition experimental measurement apparatus according to claim 1 or 2, characterized by: The cavity III is a conical cavity.

8. The spontaneous imbibition experimental measurement apparatus according to claim 1 or 2, characterized by: A switch is arranged on the crude oil injection pipeline and the imbibition liquid injection pipeline.

9. The spontaneous imbibition experimental measurement apparatus according to claim 1 or 2, characterized by: The intermediate container I and the intermediate container II are connected with the ISCO pump.

10. Use of the spontaneous imbibition measuring device according to any one of claims 1 to 9 for the measurement of spontaneous imbibition under simulated reservoir and field development conditions.

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