Rock core wettability testing device

Abstract

The utility model discloses a rock core wettability measuring device which comprises a total container, a rock core holder is arranged in the total container, an oil bath box is arranged on one side of the total container, an oil container is arranged between the oil bath box and the total container, a water container is arranged on one side, far away from the oil bath box, of the total container, and the oil container and the water container are respectively connected with the total container through connecting pipes. One side of the water container away from the main container is connected with a vacuum pump through a pipeline, and the other side of the vacuum pump is connected with a gas cylinder through a pipeline. According to the utility model, the water container and the oil container are arranged, so that the reaction is quicker; through the arrangement of the vacuum pump, the measurement result is more accurate; through the arrangement of the gas cylinder, the rock core holder and the oil bath box, the temperature and the pressure in a measurement system are accurately controlled, wettability measurement under different temperature and confining pressure conditions can be carried out according to specific requirements, and the self-absorption amount and the self-absorption rate of the rock core can be judged through the change of scales on the water container and the oil container.

Description

Technical Field

[0001] The utility model relates to the technical field of core testing devices, in particular to a core wettability testing device. Background Art

[0002] Core wettability refers to the oil-wetting or water-wetting properties of a core sample. Wettability determines the movement of fluids within the core and can influence fluid adsorption, retention, and diffusion. Core wettability testing provides a deeper understanding of these interactions, providing theoretical support for solving reservoir engineering problems. Core wettability significantly influences parameters such as fluid flow and permeability during oil and gas development. Therefore, measuring core wettability is crucial for effectively assessing reservoir properties and development potential. However, external factors can significantly influence the characteristics of core wettability. Therefore, designing a device that can accurately control variables for measuring core wettability is crucial for more rapid and accurate assessment of rock wettability. Currently, many researchers have conducted research on both quantitative and qualitative core wettability analysis methods. Commonly used quantitative analysis methods in the laboratory include contact angle, relative permeability curves, imbibition rate, and the Amott method. Qualitative methods for identifying reservoir wettability include resistivity logging and electrical logging-assisted RFT formation testing. The wettability of cores is usually obtained through laboratory measurements, but these methods have certain limitations, such as requiring a large amount of samples, taking a long time, high cost, and being easily affected by external conditions.

[0003] For example, patent application publication number CN219590148U, "A Diaphragm Wettability Testing Device" (published on August 25, 2023), discloses a diaphragm wettability testing device designed to address the complex structure, difficult operation, low efficiency, and poor accuracy of existing devices for evaluating membrane wettability. However, the device's fixed dimensions make it difficult to reflect the long-term wettability of the membrane. Furthermore, the device fails to consider the effect of pressure on membrane wettability, making it unable to comprehensively assess membrane performance under various conditions. Patent application publication number CN102393351B, "A Rock Wettability Testing Method and Device" (published on July 31, 2013), discloses a rock wettability testing method and device. This device, which uses a vertically positioned core and a water-injection and oil-injection / water-injection method to measure the wettability of rock samples, meets the high-temperature and high-pressure conditions of oil reservoirs and is easy to operate, addressing the problem of existing wettability measurement methods that fail to account for high temperatures and high pressures. However, the sample in this device comes into contact with the fluid, destroying the internal structure of the sample; and the device is not isolated from the air, which is not conducive to judging the accuracy of the results; the device is a unidirectional flow of oil driving water or water driving oil, which has the problem of slow and time-consuming measurement.

[0004] In summary, although the research on the methods of core wettability characteristics has been gradually developed, there are few devices for controlling variables and measuring core wettability characteristics. The existing devices have problems such as complex process, long time consumption, high cost, inaccurate data, and insufficient standardization in the process of core wettability measurement. Therefore, it is necessary to design a core wettability test device that can adjust variables and reduce errors caused by external conditions and can be applied in practice, so as to ensure a better understanding of the wettability characteristics of rocks and provide more accurate data support for oil exploration and production. Utility Model Content

[0005] The purpose of the utility model is to provide a core wettability testing device, which solves the problems existing in the prior art such as slow and time-consuming measurement, inaccurate measurement results, and inability to accurately control temperature and pressure.

[0006] The technical solution adopted by the utility model is that the core wettability testing device includes a main container, a core clamp is placed inside the main container, an oil bath box is provided on one side of the main container, an oil container is provided between the oil bath box and the main container, a water container is provided on the side of the main container away from the oil bath box, the oil container and the water container are respectively connected to the main container through connecting pipes, the side of the water container away from the main container is connected to a vacuum pump through a pipeline, and the other side of the vacuum pump is connected to a gas cylinder through a pipeline.

[0007] The utility model is also characterized in that:

[0008] The outside of the main container is connected to a second pressure gauge through an electric wire.

[0009] The outside of the oil bath is connected to a temperature gauge via an electric wire.

[0010] The temperature gauge is connected to a second pressure gauge via an electric wire.

[0011] A bracket is provided below the main container.

[0012] Both the water container and the oil container are marked with scales.

[0013] A water regulating switch is provided on the pipe of the water container.

[0014] An oil regulating switch is provided on the pipeline of the oil container.

[0015] A vacuum valve is provided on the pipeline of the vacuum pump.

[0016] A gas extraction valve is provided on the pipeline of the gas cylinder, and an outer wire of the gas cylinder is connected to a first pressure gauge.

[0017] The beneficial effects of the utility model are:

[0018] 1. The core wettability testing device of the utility model is provided with a water container and an oil container. By adjusting the water and oil switches, the core is simultaneously self-primed. This two-way flow can effectively shorten the core wettability measurement time, make the reaction more rapid, and thus complete the experiment in a short time.

[0019] 2. The core wettability testing device of the utility model can isolate the interference of air during measurement through the setting of a vacuum pump. Without destroying the core sample, the wettability of rock samples with mixed wettability can be measured, which solves the problem of inaccurate measurement results caused by the lack of air isolation in the existing technology.

[0020] 3. This new core wettability testing device achieves changes in the pressure of the measurement system through the configuration of a gas cylinder and a core holder; and changes in the temperature of the measurement system through the configuration of an oil bath. This device achieves precise control of the temperature and pressure in the measurement system. By adjusting parameters such as pressure, temperature, and time to simulate various wetting conditions, wettability measurements can be performed under different temperature and confining pressure conditions according to specific needs, thereby providing a more comprehensive understanding of the wettability characteristics of the core.

[0021] 4. In the core wettability testing device of the present invention, the water container and the oil container are marked with scales, and the self-imbibition amount and self-imbibition rate of the core can be determined by the changes in the scales. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the core wettability testing device of the utility model.

[0023] In the figure: 1. Gas cylinder, 2. First pressure gauge, 3. Vacuum pump, 4. Air extraction valve, 5. Vacuum extraction valve, 6. Oil adjustment switch, 7. Water adjustment switch, 8. Water container, 9. Second pressure gauge, 10. Main container, 11. Core holder, 12. Bracket, 13. Connecting pipe, 14. Oil container, 15. Oil bath, 16. Thermometer. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0025] Example 1

[0026] like Figure 1As shown, the core wettability testing device includes a main container 10, inside which a core holder 11 is placed, through which the confining pressure can be changed. An oil bath 15 is provided on one side of the main container 10, and an oil container 14 is provided between the oil bath 15 and the main container 10. A water container 8 is provided on the side of the main container 10 away from the oil bath 15. The oil container 14 and the water container 8 are respectively connected to the main container 10 via connecting pipes 13. The side of the water container 8 away from the main container 10 is connected to a vacuum pump 3 via a pipeline, and the other side of the vacuum pump 3 is connected to a gas cylinder 1 via a pipeline. The gas cylinder 1 can adjust the displacement pressure at one end of the core according to different needs.

[0027] Example 2

[0028] A second pressure gauge 9 is connected to the outside of the main container 10 via electrical wires, and a thermometer 16 is connected to the outside of the oil bath 15 via electrical wires. During the experiment, the temperature of the reaction system can be adjusted by adjusting the oil bath 15 according to the experimental needs. The thermometer 16 can display the actual temperature during the experiment. The thermometer 16 is connected to the second pressure gauge 9 via electrical wires. A bracket 12 is provided below the main container 10.

[0029] Example 3

[0030] Both the water container 8 and the oil container 14 are marked with scales. The pipe connecting the water container 8 is equipped with a water adjustment switch 7, while the pipe connecting the oil container 14 is equipped with an oil adjustment switch 6. The scales on both the water container 8 and the oil container 14 are marked, and the changes in the scales can be observed to determine the rock's hydrophilicity and lipophilicity. A vacuum valve 5 is installed on the pipe connecting the vacuum pump 3. The vacuum pump 3 and the vacuum valve 5 can evacuate air, reducing test errors and ensuring more accurate test results. A gas extraction valve 4 is installed on the pipe connecting the gas cylinder 1. A first pressure gauge 2 is connected to the outer wires of the gas cylinder 1. This valve 4 and the first pressure gauge 2 can accurately adjust the displacement pressure at different ports, thereby measuring the wettability of the rock at different displacement pressures.

[0031] The working principle of the present invention is as follows: place the core sample on the core holder 11, inject oil into the oil bath box 15, observe the second pressure gauge 9, and according to the experimental needs, apply a certain confining pressure through the core holder 11 until the confining pressure reaches the experimental needs. Open the vacuum valve 5, the oil adjustment switch 6 and the water adjustment switch 7, and turn on the vacuum pump 3 to exhaust the air in the container through the vacuum pump 3. Open the air extraction valve 4, observe the first pressure gauge 2, and according to the experimental needs, increase a certain displacement pressure through the gas cylinder 1. According to the temperature requirements of the experiment, the thermometer 16 can be observed. If the temperature does not meet the standard, the system temperature can be changed by setting the oil bath box 15, and the same amount of oil and water can be injected into the water container 8 and the oil container 14 respectively. Finally, the self-imbibition amount and self-imbibition rate of the core can be judged by observing the changes in the scales on the water container 8 and the oil container 14.

[0032] This device determines the wettability of cores with mixed wettability while taking connectivity into account. Core wettability determines the distribution, adsorption, and desorption behavior of fluids within the core. Selecting appropriate drilling fluids based on the changing characteristics of core wettability has a significant impact on oilfield recovery. The quality of oil production engineering design is directly related to the development and economic benefits of the oilfield. Core wettability testing can assess the impact of wettability on recovery, providing a basis for optimizing oil production engineering plans. Core wettability testing provides a comprehensive understanding of the fluid behavior and core characteristics of the reservoir, providing a basis for optimizing oil production engineering plans and improving recovery and economic benefits. During oilfield development and production, various parameters must be continuously monitored and adjusted to ensure recovery and economic benefits. The core wettability testing device provides real-time insights into the fluid behavior and core characteristics of the reservoir, providing a reliable basis for guiding oilfield development and production.

Claims

1. Core wettability testing device, characterized in that: The invention comprises a main container (10), wherein a core holder (11) is placed inside the main container (10), an oil bath box (15) is provided on one side of the main container (10), an oil container (14) is provided between the oil bath box (15) and the main container (10), a water container (8) is provided on the side of the main container (10) away from the oil bath box (15), the oil container (14) and the water container (8) are respectively connected to the main container (10) through a connecting pipe (13), the side of the water container (8) away from the main container (10) is connected to a vacuum pump (3) through a pipeline, and the other side of the vacuum pump (3) is connected to a gas cylinder (1) through a pipeline.

2. The core wettability testing device according to claim 1, characterized in that: The outside of the main container (10) is connected to a second pressure gauge (9) via an electric wire.

3. The core wettability testing device according to claim 2, characterized in that: The outside of the oil bath box (15) is connected to a temperature gauge (16) via an electric wire.

4. The core wettability testing device according to claim 3, characterized in that: The temperature gauge (16) is connected to a second pressure gauge (9) via an electric wire.

5. The core wettability testing device according to claim 1, characterized in that: A bracket (12) is provided below the main container (10).

6. The core wettability testing device according to claim 1, characterized in that: The water container (8) and the oil container (14) are both marked with scales.

7. The core wettability testing device according to claim 6, characterized in that: A water regulating switch (7) is provided on the pipe of the water container (8).

8. The core wettability testing device according to claim 6, characterized in that: An oil regulating switch (6) is provided on the pipeline of the oil container (14).

9. The core wettability testing device according to claim 1, characterized in that: A vacuum valve (5) is provided on the pipeline of the vacuum pump (3).

10. The core wettability testing device according to claim 1, characterized in that: An air extraction valve (4) is provided on the pipeline of the gas cylinder (1), and an outer electric wire of the gas cylinder (1) is connected to a first pressure gauge (2).

Images