Device and method for researching free movement of imbibition oil drops

Abstract

The invention discloses a device and a method for researching free movement of imbibition oil drops. The device comprises an imbibition system, a confining pressure system, a displacement measurement system, a time measurement device and an auxiliary system, the imbibition system comprises an imbibition bottle and a core holder, and the imbibition bottle is connected with an outlet of the core holder; the confining pressure system is connected with the core holder; the displacement measuring system comprises an optical microscope system and a displacement ruler, the optical microscope system is arranged on one side of the imbibition bottle, and the displacement ruler is arranged on the lower portion of the imbibition bottle; the auxiliary system comprises an oil sample injection system and a temperature control system; the oil sample injection system comprises a constant-pressure and constant-speed displacement pump and an intermediate container, the intermediate container is connected to an inlet of the core holder, and the constant-pressure and constant-speed displacement pump is connected with the lower end of the intermediate container; the temperature control system comprises a constant-temperature box, and the imbibition bottle, the core holder and the intermediate container are all arranged in the constant-temperature box. According to the invention, the free movement capability of imbibition oil drops under different conditions can be accurately measured.

Description

Technical Field

[0001] The invention relates to the technical field of interfacial tension regulation, and in particular to a device and method for studying the free movement of imbibed oil droplets. Background Art

[0002] Imbibition is an effective method for exploiting crude oil in matrix pores. It refers to the process of spontaneous absorption of a certain wetting phase fluid into porous media (such as cracks and pores). When the matrix pores are saturated with a certain fluid, they will be exposed to a new fluid with stronger wettability, and the pore throat will spontaneously absorb the new fluid with stronger wettability. The fluid with stronger wettability enters the matrix pores and replaces the original fluid. This process is particularly important when exploiting low permeability reservoirs, because crude oil in low permeability reservoirs is often difficult to exploit through conventional displacement methods, and imbibition can use natural forces such as capillary force to displace crude oil from tiny pores. Traditional imbibition instruments have a wide range of application value in oil and gas field development. Through imbibition experiments, we can deeply understand the seepage characteristics of the reservoir, the flow law of crude oil, and the changes in recovery rate under different exploitation methods. This information is of great significance for formulating scientific and reasonable exploitation plans, improving recovery rates, and reducing exploitation costs.

[0003] Since traditional dialyzers usually only include one dialysis bottle for simple observation of the dialysis process, there are problems such as uncertain dialysis area, complex oil droplet motion state and difficulty in accurate measurement. In particular, when studying the motion characteristics of oil droplets under the combined effects of gravity and free motion between molecules, there is a lack of a device that can accurately measure the relationship between the free motion time and displacement of oil droplets. Therefore, there is an urgent need in this field for a test device that can comprehensively consider multiple factors such as temperature, pressure, and surfactants to accurately measure the free motion ability of oil droplets. Summary of the invention

[0004] The purpose of the present invention is to provide a device and method for studying the free movement of imbibed oil droplets, so as to solve the problems existing in the above-mentioned prior art and to accurately measure the free movement ability of imbibed oil droplets under different conditions.

[0005] To achieve the above object, the present invention provides the following solutions: The present invention provides a device for studying the free movement of imbibed oil droplets, comprising an imbibed system, a confining pressure system, a displacement measurement system, a time measurement device and an auxiliary system; The infiltration system comprises an infiltration bottle and a core holder, wherein the inlet at the lower end of the infiltration bottle is connected to the outlet at the upper end of the core holder; The confining pressure system is connected to the core holder and is used to provide confining pressure for the core inside the core holder; The displacement measurement system includes an optical microscope system and a displacement ruler, wherein the optical microscope system is arranged at one side of the infiltration bottle, and the displacement ruler is arranged at the lower part of the infiltration bottle; the time measurement device is used to record the time for the oil droplets to move in the infiltration bottle; the optical microscope system, the displacement ruler and the time measurement device are all connected to a computer for communication; The auxiliary system includes an oil sample injection system and a temperature control system; the oil sample injection system includes a constant pressure and constant speed displacement pump and an intermediate container, the upper end of the intermediate container is connected to the lower inlet of the core clamp, and the constant pressure and constant speed displacement pump is connected to the lower end of the intermediate container; the temperature control system includes a constant temperature box, and the infiltration bottle, the core clamp and the intermediate container are all arranged in the constant temperature box.

[0006] In one embodiment, the confining pressure system includes a confining pressure pump and a pressure gauge, the confining pressure pump is connected to the confining pressure port of the core holder through a confining pressure pipeline, and the pressure gauge is arranged on the confining pressure pipeline.

[0007] In one embodiment, the imbibition bottle is an ultra-white glass imbibition bottle, and the intermediate container is an ultra-white glass intermediate container.

[0008] In one embodiment, the lower portion of the imbibition bottle is threadedly connected to the core holder.

[0009] In one embodiment, a rubber sleeve is provided in the core holder for fixing the core.

[0010] In one embodiment, the door of the thermostatic box is an ultra-white glass door, and the optical microscope system collects images of the infiltration bottle through the ultra-white glass door.

[0011] In one embodiment, volume graduations are provided on the intermediate container.

[0012] The present invention also provides a method for studying the free movement of imbibed oil droplets, based on the above-mentioned device for studying the free movement of imbibed oil droplets, comprising the following steps: The experimental cores were first washed with oil, dried and the dry weight of the cores was measured after the oil washing treatment; After the core is vacuum-saturated with formation water, the wet weight is measured and the core pore volume is calculated to simulate the state of the core in the formation; placing a core into the core holder, and applying confining pressure to the core in the core holder through the confining pressure system; After the intermediate container and the core holder are connected, water is injected into the intermediate container by the constant pressure and constant speed displacement pump to make the oil sample in the intermediate container move upward until the core in the core holder is fully saturated with the oil sample; Filling the surfactant solution into the absorption bottle, connecting the absorption bottle to the upper outlet of the core holder, and controlling the temperature at a constant temperature through the thermostat; The constant pressure and constant speed displacement pump is controlled to inject the experimental oil sample into the core holder. During the injection process, the movement of the oil droplets is monitored collaboratively by the optical microscope system and the displacement ruler, and the movement time of the oil droplets in the imbibition bottle is recorded by the time measuring device. The collected data is transmitted to the computer for processing and analysis.

[0013] Compared with the prior art, the present invention has achieved the following technical effects: The present invention provides a device and method for studying the free movement of imbibed oil droplets. The confining pressure is provided to the core by a confining pressure system, the oil sample can be stably driven into the core holder by an oil sample injection system, the temperature during the experiment can be controlled to remain constant by a temperature control system, the displacement and time of the imbibed oil droplets can be accurately measured by a displacement measurement system and a time measurement device, and the free movement results of the imbibed oil droplets are obtained by computer processing and analysis. In the present invention, the experimental confining pressure can be adjusted by the confining pressure system, the experimental temperature can be controlled by the temperature control system, the pressure and speed of the oil sample driving can be controlled by the oil sample injection system, different surfactants can be replaced, and the free movement ability of the oil droplets under different emulsion concentrations can be tested, thereby realizing the accurate measurement of the free movement ability of the imbibed oil droplets under different conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 It is a schematic diagram of the structure of the device for studying the free movement of imbibed oil droplets in an embodiment of the present invention.

[0016] In the figure: 1-imbibition bottle, 2-core holder, 3-optical microscope system, 4-computer, 5-constant pressure and constant speed displacement pump, 6-intermediate container, 7-constant temperature box, 8-confining pressure pump, 9-pressure gauge. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] The purpose of the present invention is to provide a device and method for studying the free movement of imbibed oil droplets, so as to solve the problems existing in the prior art and to accurately measure the free movement ability of imbibed oil droplets under different conditions.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Embodiment 1 like Figure 1 As shown, this embodiment provides a device for studying the free movement of imbibed oil droplets, including an imbibition system, a confining pressure system, a displacement measurement system, a time measurement device and an auxiliary system; The infiltration system includes an infiltration bottle 1 and a core holder 2. The inlet at the lower end of the infiltration bottle 1 is connected to the outlet at the upper end of the core holder 2. A rubber sleeve is provided in the core holder 2 to fix the core and ensure sealing. The confining pressure system is connected to the core holder 2 and is used to provide confining pressure for the core inside the core holder 2; The displacement measurement system includes an optical microscope system 3 and a displacement ruler, wherein the optical microscope system 3 is arranged on one side of the infiltration bottle 1, and the displacement ruler is arranged at the lower part of the infiltration bottle 1; the time measurement device is used to record the time for the oil drop to move from bottom to top in the infiltration bottle 1; the optical microscope system 3, the displacement ruler and the time measurement device are all connected to the computer 4 for communication; The auxiliary system includes an oil sample injection system and a temperature control system; the oil sample injection system includes a constant pressure and constant speed displacement pump 5 and an intermediate container 6, the upper end of the intermediate container 6 is connected to the lower inlet of the core clamp 2, and the constant pressure and constant speed displacement pump 5 is connected to the lower end of the intermediate container 6; the temperature control system includes a constant temperature box 7, and the infiltration bottle 1, the core clamp 2 and the intermediate container 6 are all arranged in the constant temperature box 7.

[0021] Among them, the infiltration bottle 1 adopts a conical infiltration bottle, whose bottom is a small end and the upper part is a large end. The small end at the bottom of the infiltration bottle 1 is connected to the upper end of the core clamp 2. The infiltration bottle 1 adopts a conical structure, so that the infiltration bottle 1 has a sufficiently wide migration channel. When the oil droplets are released from bottom to top, it is ensured that the oil droplets can migrate freely in the infiltration bottle 1 without contacting the side wall of the infiltration bottle 1; the body of the infiltration bottle 1 is provided with scale lines, which can assist in observing the displacement of the oil droplets. The infiltration bottle 1 uses an ultra-white glass infiltration bottle to ensure clear observation of the migration of the oil droplets to the greatest extent. The infiltration bottle 1 can be filled with a surfactant solution, and the lower part of the infiltration bottle 1 is provided with a thread, which is connected to the core clamp 2 through the thread.

[0022] The constant pressure and constant speed displacement pump 5 can maintain a constant flow and pressure output, ensuring that the oil sample is stably driven into the core holder 2. The intermediate container 6 is an ultra-white glass intermediate container. The intermediate container 6 is provided with a volume scale line to facilitate recording the input oil sample volume.

[0023] The thermostat 7 is used to accurately control the temperature in the infiltration system to ensure that the action temperature of the surfactant is met. The door of the thermostat 7 is an ultra-white glass door, which facilitates the optical microscope system 3 to collect images of the infiltration bottle 1 through the ultra-white glass door.

[0024] The confining pressure system includes a confining pressure pump 8 and a pressure gauge 9. The confining pressure pump 8 is connected to the confining pressure port of the core holder 2 through a confining pressure pipeline, and the pressure gauge 9 is arranged on the confining pressure pipeline. By cooperating with the confining pressure pump 8 and the pressure gauge 9, the confining pressure can be accurately controlled to coordinately control the migration direction of the fluid to always be upward.

[0025] The device provides confining pressure to the core through a confining pressure system, can stably drive the oil sample into the core holder 2 through an oil sample injection system, can control the temperature during the experiment to remain constant through a temperature control system, can accurately measure the displacement and time of the imbibed oil droplets through a displacement measurement system and a time measurement device, and obtain the free movement results of the imbibed oil droplets through computer processing and analysis; the experimental confining pressure can be adjusted by the confining pressure system, the experimental temperature can be controlled by the temperature control system, the pressure and speed of the oil sample driving can be controlled by the oil sample injection system, different surfactants can be replaced, and the free movement ability of the oil droplets under different emulsion concentrations can be tested, thereby realizing the accurate measurement of the free movement ability of the imbibed oil droplets under different conditions.

[0026] Embodiment 2 This embodiment provides a method for studying the free movement of imbibed oil droplets, based on the device for studying the free movement of imbibed oil droplets described in embodiment 1, comprising the following steps: Before the experiment, the experimental cores were washed with oil, dried and the dry weight of the cores was measured after the oil washing treatment; After the core is vacuum-saturated with formation water, the wet weight is measured and the core pore volume is calculated to simulate the state of the core in the formation; After the core is placed in the core holder 2, a confining pressure is applied to the core in the core holder 2 by a confining pressure pump; After the intermediate container 6 is connected to the core holder 2, water is injected into the intermediate container 6 through the constant pressure and constant speed displacement pump 5, so that the oil sample in the intermediate container 6 moves upward until the core in the core holder 2 is fully saturated with the oil sample; when injecting, inject slowly at a constant speed, and when no water comes out of the outlet of the core holder 2, it means that the oil sample is fully saturated; A surfactant solution is placed in the imbibition bottle 1, the type and concentration of which are adjusted according to the conditions required by the experiment, and the imbibition bottle 1 is connected to the upper outlet of the core holder 2, and the temperature is controlled at a constant temperature by a thermostat 7; The constant pressure and constant speed displacement pump 5 is controlled to select different pressures or speeds to inject the oil sample into the core holder 2. During the injection process, the movement of the oil droplets is monitored in coordination with the optical microscope system 3 and the displacement ruler, and the time for the oil droplets to move from bottom to top in the infiltration bottle 1 is recorded by the time measuring device. The collected data is transmitted to the computer 4, which processes and analyzes it.

[0027] The experiment was stopped when the injected oil volume was equal to or greater than the pore volume of the core.

[0028] During the experiment, when the confining pressure is applied to the core in the core holder 2 by the confining pressure pump, the pressure on the rubber sleeve inside the core holder 2 is always greater than the displacement pressure (i.e., the output pressure of the constant pressure and constant speed displacement pump 5). For example, it can be set to always be greater than the displacement pressure by 2 MPa to ensure that the displaced oil sample will not flow in the gap between the core holder 2 and the core.

[0029] During the injection process, an auxiliary system is used to control the temperature, pressure and speed of the injection, and a high-precision displacement measurement system is used to monitor the subtle movement of the oil droplets. Different surfactants can be replaced to test the free movement ability of the oil droplets under different emulsion concentrations. The vertical movement ability of the oil droplets is relatively strong. At the same time, the movement of each segment has different characteristics, and the free movement ability of the oil droplets in each micro-element segment can be measured.

[0030] When the oil sample flows into the surfactant solution and the oil droplets are released from bottom to top, the relationship between the displacement of a single oil droplet and time can be measured experimentally.

[0031] After shooting and imaging by a high-precision displacement measurement system, the free diffusion of oil droplets in the surfactant solution can be regarded as linear motion, so an approximate functional relationship can be fitted based on the experimental data to describe the relationship between the free motion time t and the displacement s of the oil droplets. The displacement of the oil droplets at different time points can be measured experimentally, and a curve of the displacement s versus time t can be plotted to observe the trends and characteristics of the data, and based on the trends and characteristics of the data, the following functional forms can be selected as candidates.

[0032] in: D （C） is the diffusion coefficient of the oil droplet in the surfactant solution; S (r,T,C) It is the time interval of the oil droplet along a certain "average" straight line direction. t The total displacement generated at the end of the process (the displacement of the oil droplet is affected by parameters such as the oil droplet radius r, time T, and concentration C); t is the time interval; S (0) is the initial displacement of the oil droplet at the initial moment of time interval t.

[0033] This definition and relationship are specified and simplified under the conditions of this experimental equipment. In the real diffusion process, the displacement of oil droplets is random, three-dimensional, and affected by many factors. Therefore, this simplified model is only applicable under such specific conditions and assumptions.

[0034] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A device for studying the free movement of imbibed oil droplets, characterized in that: It includes the imbibition system, confining pressure system, displacement measurement system, time measurement device and auxiliary system; The infiltration system comprises an infiltration bottle and a core holder, wherein the inlet at the lower end of the infiltration bottle is connected to the outlet at the upper end of the core holder; The confining pressure system is connected to the core holder and is used to provide confining pressure for the core inside the core holder; The displacement measurement system includes an optical microscope system and a displacement ruler, wherein the optical microscope system is arranged at one side of the infiltration bottle, and the displacement ruler is arranged at the lower part of the infiltration bottle; the time measurement device is used to record the time for the oil droplets to move in the infiltration bottle; the optical microscope system, the displacement ruler and the time measurement device are all connected to a computer for communication; The auxiliary system includes an oil sample injection system and a temperature control system; the oil sample injection system includes a constant pressure and constant speed displacement pump and an intermediate container, the upper end of the intermediate container is connected to the lower inlet of the core clamp, and the constant pressure and constant speed displacement pump is connected to the lower end of the intermediate container; the temperature control system includes a constant temperature box, and the infiltration bottle, the core clamp and the intermediate container are all arranged in the constant temperature box.

2. The device for studying the free movement of imbibed oil droplets according to claim 1, characterized in that: The confining pressure system comprises a confining pressure pump and a pressure gauge. The confining pressure pump is connected to the confining pressure port of the core holder through a confining pressure pipeline, and the pressure gauge is arranged on the confining pressure pipeline.

3. The device for studying the free movement of imbibed oil droplets according to claim 1, characterized in that: The infiltration bottle is an ultra-white glass infiltration bottle, and the intermediate container is an ultra-white glass intermediate container.

4. The device for studying the free movement of imbibed oil droplets according to claim 1, characterized in that: The lower part of the imbibition bottle is threadedly connected to the core holder.

5. The device for studying the free movement of imbibed oil droplets according to claim 1, characterized in that: The core holder is provided with a rubber sleeve for fixing the core.

6. The device for studying the free movement of imbibed oil droplets according to claim 1, characterized in that: The door of the constant temperature box is an ultra-white glass door, and the optical microscope system collects images of the infiltration bottle through the ultra-white glass door.

7. The device for studying the free movement of imbibed oil droplets according to claim 1, characterized in that: The intermediate container is provided with volume graduations.

8. A method for studying the free movement of imbibed oil droplets, characterized in that: The device for studying the free movement of imbibed oil droplets according to any one of claims 1 to 7 comprises the following steps: The experimental cores were first washed with oil, and then dried and the dry weight of the cores was measured; After the core is vacuum-saturated with formation water, the wet weight is measured and the core pore volume is calculated to simulate the state of the core in the formation; placing a core into the core holder, and applying confining pressure to the core in the core holder through the confining pressure system; After the intermediate container and the core holder are connected, water is injected into the intermediate container by the constant pressure and constant speed displacement pump to make the oil sample in the intermediate container move upward until the core in the core holder is fully saturated with the oil sample; Filling the surfactant solution into the absorption bottle, connecting the absorption bottle to the upper outlet of the core holder, and controlling the temperature at a constant temperature through the thermostat; The constant pressure and constant speed displacement pump is controlled to inject the experimental oil sample into the core holder. During the injection process, the movement of the oil droplets is monitored collaboratively by the optical microscope system and the displacement ruler, and the movement time of the oil droplets in the imbibition bottle is recorded by the time measuring device. The collected data is transmitted to the computer for processing and analysis.

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