An apparatus and method for studying the free movement of imbibed oil droplets

Abstract

The present invention discloses a device and method for studying the free movement of imbibed oil droplets. The device includes an imbibition system, a confining pressure system, a displacement measurement system, a time measurement device, and an auxiliary system. The imbibition system includes an imbibition bottle and a core holder, and the imbibition bottle is connected to the outlet of the core holder. The confining pressure system is connected to the core holder. The displacement measurement system includes an optical microscope system and a displacement scale. The optical microscope system is arranged on one side of the imbibition bottle, and the displacement scale is arranged at the lower part of the imbibition bottle. 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 intermediate container is connected to the inlet of the core holder, 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 imbibition bottle, the core holder, and the intermediate container are all arranged in the constant temperature box. The present invention can accurately measure the free movement ability of imbibed oil droplets under different conditions.

Description

Technical Field

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

[0002] Imbibition is an effective method for extracting crude oil from matrix pores. It refers to the process in which a certain wetting-phase fluid spontaneously sucks into a porous medium (such as fractures and pores). When the matrix pores are saturated with a certain fluid and come into contact with a new fluid with stronger wettability, imbibition will occur spontaneously in the pore throats, and the fluid with stronger wettability will enter the matrix pores to displace the original fluid. This process is particularly important in the exploitation of low-permeability reservoirs because the crude oil in low-permeability reservoirs is often difficult to extract by conventional displacement methods, while imbibition can use natural forces such as capillary force to displace the crude oil from tiny pores. Traditional imbibition meters have wide application value in oil and gas field development. Through imbibition experiments, the seepage characteristics of reservoirs, the flow laws of crude oil, and the changes in recovery rates under different exploitation methods can be deeply understood. These information is of great significance for formulating scientific and reasonable exploitation plans, increasing recovery rates, and reducing exploitation costs, etc.

[0003] Since traditional dialysis meters usually only contain one dialysis bottle for simply observing the dialysis process, there are problems such as uncertain dialysis area, complex movement states of oil droplets, and difficulty in accurate measurement. Especially when studying the movement characteristics of oil droplets under the combined action of gravity and intermolecular free movement, there is a lack of a device that can accurately measure the relationship between the free movement time and displacement of oil droplets. Therefore, there is an urgent need in this field for a test device that can comprehensively consider various factors such as temperature, pressure, and surfactants and accurately measure the free movement 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 imbibition oil droplets to solve the problems existing in the above-mentioned prior art and be able to accurately measure the free movement ability of imbibition oil droplets under different conditions.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] The present invention provides a device for studying the free movement of imbibition oil droplets, including an imbibition system, a confining pressure system, a displacement measurement system, a time measurement device, and an auxiliary system;

[0007] The imbibition system includes an imbibition bottle and a core holder, and the lower inlet of the imbibition bottle is connected to the upper outlet of the core holder;

[0008] The confining pressure system is connected to the core holder and is used to provide confining pressure for the core inside the core holder;

[0009] The displacement measurement system includes an optical microscope system and a displacement scale. The optical microscope system is arranged on one side of the imbibition bottle, and the displacement scale is arranged at the lower part of the imbibition bottle. The time measurement device is used to record the time when the oil droplet moves in the imbibition bottle. The optical microscope system, the displacement scale and the time measurement device are all communicatively connected to a computer.

[0010] 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 holder, 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 imbibition bottle, the core holder and the intermediate container are all arranged in the constant-temperature box.

[0011] 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.

[0012] In one embodiment, the imbibition bottle is a ultra-clear glass imbibition bottle, and the intermediate container is a ultra-clear glass intermediate container.

[0013] In one embodiment, the lower part of the imbibition bottle is threadedly connected to the core holder.

[0014] In one embodiment, a rubber sleeve is arranged inside the core holder for fixing the core.

[0015] In one embodiment, the door of the constant-temperature box is a ultra-clear glass door, and the optical microscope system collects images of the imbibition bottle through the ultra-clear glass door.

[0016] In one embodiment, the intermediate container is provided with volume graduation lines.

[0017] The present invention also provides a method for studying the free movement of imbibition oil droplets. Based on the device for studying the free movement of imbibition oil droplets described above, the method includes the following steps:

[0018] First, wash the experimental core with oil. After the oil washing treatment, dry it and measure the dry weight of the core.

[0019] Vacuum-saturate the core with formation water, then measure the wet weight and calculate the pore volume of the core to simulate the state of the core in the formation.

[0020] Put the core into the core holder, and apply confining pressure to the core in the core holder through the confining pressure system.

[0021] After connecting the intermediate container to the core holder, water is injected into the intermediate container through the constant pressure and constant speed displacement pump, so that the oil sample in the intermediate container migrates upward until the core in the core holder is fully saturated with the oil sample;

[0022] Load a surfactant solution into the imbibition bottle, connect the imbibition bottle to the upper outlet of the core holder, and control the temperature at a constant temperature through the constant temperature box;

[0023] Control the constant pressure and constant speed displacement pump, inject an experimental oil sample into the core holder. During the injection process, the migration of oil droplets is monitored collaboratively by the optical microscope system and the displacement ruler, and the time measuring device records the time for the oil droplets to move in the imbibition bottle. The collected data is transmitted to the computer for processing and analysis by the computer.

[0024] The present invention has achieved the following technical effects compared with the prior art:

[0025] The device and method for studying the free movement of imbibition oil droplets provided by the present invention provide confining pressure for the core through the confining pressure system, can stably drive the oil sample into the core holder through the oil sample injection system, can control the temperature to remain constant during the experiment through the temperature control system, can accurately measure the displacement and time of the imbibition oil droplets through the displacement measurement system and the time measuring device, and obtain the free movement result of the imbibition oil droplets through 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 oil sample injection can be controlled by the oil sample injection system, different surfactants can be replaced, and the free movement ability of oil droplets under different emulsion concentrations can be tested, so as to realize the accurate measurement of the free movement ability of imbibition oil droplets under different conditions. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 It is a schematic structural diagram of the device for studying the free movement of imbibition oil droplets in the embodiments of the present invention.

[0028] 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 Embodiments

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] The purpose of the present invention is to provide a device and method for studying the free movement of imbibition oil droplets, so as to solve the problems existing in the prior art and be able to accurately measure the free movement ability of imbibition oil droplets under different conditions.

[0031] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] Embodiment 1

[0033] As Figure 1 shown, this embodiment provides a device for studying the free movement of imbibition oil droplets, including an imbibition system, a confining pressure system, a displacement measurement system, a time measurement device, and an auxiliary system;

[0034] The imbibition system includes an imbibition bottle 1 and a core holder 2. The lower inlet of the imbibition bottle 1 is connected to the upper outlet of the core holder 2; a rubber sleeve is provided inside the core holder 2 to fix the core and ensure tightness;

[0035] The confining pressure system is connected to the core holder 2 to provide confining pressure for the core inside the core holder 2;

[0036] The displacement measurement system includes an optical microscope system 3 and a displacement scale. The optical microscope system 3 is arranged on one side of the imbibition bottle 1, and the displacement scale is arranged at the lower part of the imbibition bottle 1; the time measurement device is used to record the time when the oil droplet moves from bottom to top in the imbibition bottle 1; the optical microscope system 3, the displacement scale, and the time measurement device are all communicatively connected to a computer 4;

[0037] 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 holder 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 imbibition bottle 1, the core holder 2, and the intermediate container 6 are all arranged inside the constant temperature box 7.

[0038] Among them, the imbibition bottle 1 is a conical imbibition bottle, with its bottom being the small end and the upper part being the large end. The small end of the bottom of the imbibition bottle 1 is connected to the upper end of the core holder 2. The imbibition bottle 1 adopts a conical structure, enabling the imbibition bottle 1 to have a sufficiently wide migration channel. When the oil droplets disperse from bottom to top, it ensures that the oil droplets can freely migrate within the imbibition bottle 1 without contacting the side wall of the imbibition bottle 1. Scale lines are provided on the bottle body of the imbibition bottle 1, which can assist in observing the displacement of the oil droplets. The imbibition bottle 1 is selected as an ultra-clear glass imbibition bottle to ensure clear observation of the migration of the oil droplets to the greatest extent. The imbibition bottle 1 can be filled with a surfactant solution. The lower part of the imbibition bottle 1 is provided with threads and is connected to the core holder 2 through the threads.

[0039] The constant pressure and constant speed displacement pump 5 can maintain a constant flow rate and pressure output, ensuring that the oil sample is stably displaced into the core holder 2. The intermediate container 6 is selected as an ultra-clear glass intermediate container. Volume scale lines are provided on the intermediate container 6, which is convenient for recording the volume of the input oil sample.

[0040] The constant temperature box 7 is used to accurately control the temperature within the imbibition system to ensure that the temperature required for the surfactant to function is met. The door of the constant temperature box 7 is an ultra-clear glass door, which is convenient for the optical microscope system 3 to collect images of the imbibition bottle 1 through the ultra-clear glass door.

[0041] 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 the confining pressure pump 8 with the pressure gauge 9, the confining pressure can be accurately controlled to synergistically control the migration direction of the fluid to always be upward.

[0042] This device provides confining pressure to the core through the confining pressure system, can stably displace the oil sample into the core holder 2 through the oil sample injection system, can control the temperature during the experiment to remain constant through the temperature control system, can accurately measure the displacement and time of the imbibed oil droplets through the displacement measurement system and the time measurement device, and can 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 displacement 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, so as to realize the accurate measurement of the free movement ability of the imbibed oil droplets under different conditions.

[0043] Example Two

[0044] This example 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 Example One, it includes the following steps:

[0045] Before the experiment starts, wash the experimental core with oil, dry it after the oil washing treatment, and measure the dry weight of the core.

[0046] After vacuum-saturating the core with formation water, measure the wet weight and calculate the pore volume of the core to simulate the state of the core in the formation;

[0047] After placing the core in the core holder 2, apply confining pressure to the core in the core holder 2 through the confining pressure pump;

[0048] After connecting the intermediate container 6 to the core holder 2, inject water into the intermediate container 6 through the constant pressure and constant rate displacement pump 5 to make the oil sample in the intermediate container 6 migrate upward until the core in the core holder 2 is fully saturated with the oil sample; during injection, 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;

[0049] Load the surfactant solution into the imbibition bottle 1, the type and concentration of which are adjusted according to the experimental conditions, and connect the imbibition bottle 1 to the upper outlet of the core holder 2, and control the temperature at a constant temperature through the thermostat 7;

[0050] Control the constant pressure and constant rate displacement pump 5, select different pressures or speeds to inject the oil sample into the core holder 2. During the injection process, monitor the migration of oil droplets through the cooperation of the optical microscope system 3 and the displacement scale, and record the time for the oil droplets to move from bottom to top in the imbibition bottle 1 through the time measuring device, and transmit the collected data to the computer 4 for processing and analysis by the computer 4.

[0051] Stop the experiment when the measured injected oil volume is equal to or greater than the pore volume of the core.

[0052] During the experiment, when applying confining pressure to the core in the core holder 2 through the confining pressure pump, make the pressure on the inner rubber sleeve of the core holder 2 always greater than the displacement pressure (i.e., the output pressure of the constant pressure and constant rate 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.

[0053] During the injection process, use the auxiliary system to control the temperature, the pressure and speed of injection, use the high-precision displacement measurement system to monitor the subtle migration of oil droplets, different surfactants can be replaced to test the free movement ability of oil droplets at different emulsion concentrations. The vertical movement ability of oil droplets is relatively strong, and each section of movement has different characteristics, and the free movement ability of oil droplets in each microelement section can be measured.

[0054] When the oil sample flows into the surfactant solution and the oil droplets disperse from bottom to top, the relationship between the displacement and time of a single oil droplet can be measured through experiments.

[0055] After the oil droplets are photographed and imaged by the high-precision displacement measurement system, the free diffusion of the oil droplets in the surfactant solution can be regarded as a linear motion. Therefore, an approximate functional relationship can be fitted based on the experimental data to describe the relationship between the free motion time t of the oil droplets and the displacement s. The displacement of the oil droplets at different time points can be measured through experiments, and a curve graph of the displacement s changing with the time t can be plotted to observe the trends and characteristics of the data. According to the trends and characteristics of the data, the following functional forms are selected as candidates.

[0056]

[0057] Where:

[0058] D （C） is the diffusion coefficient of the oil droplets in the surfactant solution;

[0059] S (r,T,C) is the total displacement generated at the end moment of the time interval t by the oil droplets along a certain "average" straight-line direction (the displacement of the oil droplets is affected by parameters such as the radius r of the oil droplets, time T, concentration C, etc.);

[0060] t is the time interval;

[0061] S (0) is the initial displacement already generated by the oil droplets at the initial moment of the time interval t.

[0062] This definition and relationship are specific and simplified under the conditions of this experimental equipment. In the real diffusion process, the displacement of the oil droplets is random, three-dimensional, and affected by various factors. Therefore, this simplified model is only applicable under such specific conditions and assumptions.

[0063] In the present invention, specific examples are used to elaborate the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to 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 infiltration bottle is a conical infiltration bottle, wherein the bottom of the infiltration bottle is a small end and the upper part is a large end, and the small end at the bottom of the infiltration bottle is connected to 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, 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.

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