Flat rock core oil saturation simultaneous testing device and testing method

Abstract

The invention belongs to the technical field of oil exploration, and discloses a plate rock core oil saturation simultaneous testing device and a testing method. The plate core oil saturation simultaneous measurement device comprises a holder, a high-temperature and high-pressure reaction kettle, a nuclear magnetic resonance device, a constant-temperature box and a hand pump, a plate core is arranged in the holder, the holder is arranged in the high-temperature and high-pressure reaction kettle, and the high-temperature and high-pressure reaction kettle is located in the nuclear magnetic resonance device; a plurality of communicating seats are arranged at the upper end of the flat rock core and used for connecting the intermediate container and the oil-water metering device, a plurality of electrode pairs are arranged in the flat rock core and connected with the resistivity monitoring device, the intermediate container is used for containing simulated oil and / or simulated water, and the hand pump is connected with the clamping device. According to the invention, the fluctuation of the saturation field in the flat rock core under a real high-temperature and high-pressure reservoir condition can be tested, an irregular flow field formed by continuously changing fluid in the flat rock core can be tested, and an accurate oil saturation field can be calculated by collecting resistivity and nuclear magnetic resonance data at different stages.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum exploration, and in particular to a device and method for measuring the oil saturation of a flat core. Background Art

[0002] Using natural cores to conduct reservoir physical simulation experiments is an important means for petroleum researchers to conduct theoretical research. However, the source of natural cores is limited and the volume is small. Only the relative permeability curve, capillary pressure curve, sensitivity characteristics and other parameters of the reservoir can be obtained through natural columnar cores, which cannot reflect the characteristics of the macroscopic heterogeneity of the reservoir, the well network and the injection-production relationship. The experiment only obtains some basic physical parameters of the reservoir. In actual research, it is often necessary to consider aspects such as well network deployment, involving one injection and multiple production or multiple injections and multiple production, involving vertical heterogeneity or plane heterogeneity. At this time, a larger size of epoxy resin flat core is required. At present, the flat core oil saturation test device can only use the resistivity test method, but the resistivity value tested by this method is often not accurate enough. The experimental results obtained by the existing technology simulation are not reliable. Therefore, how to accurately test or correct the changes in oil saturation inside the flat core is an urgent problem to be solved. Summary of the invention

[0003] The purpose of the present invention is to provide a device and method for measuring the oil saturation of a flat core, so as to solve the problem that the oil saturation test of a flat core is not accurate enough.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] The flat core oil saturation joint measurement device includes:

[0006] A holder, a flat core is arranged in the holder, a plurality of connecting seats are arranged on the upper end of the flat core, a plurality of electrode pairs are arranged inside the flat core, at least one of the plurality of connecting seats is connected to an intermediate container, and the remaining connecting seats are connected to an oil-water metering device, a plurality of electrode pairs are connected to a resistivity monitoring device through a wire row, and the intermediate container is used to hold simulated oil or simulated water;

[0007] A high-temperature and high-pressure reactor, wherein the holder is placed in the high-temperature and high-pressure reactor;

[0008] A nuclear magnetic resonance device, wherein the high temperature and high pressure reactor is located inside the nuclear magnetic resonance device;

[0009] A constant temperature box, wherein the oil-water metering device, the intermediate container and the nuclear magnetic resonance device are all arranged in the constant temperature box.

[0010] Optionally, the outer side of the flat core is wrapped with epoxy resin.

[0011] Optionally, nine connecting seats are provided, which are arranged in three rows and three columns. The connecting seat in the middle is connected to the intermediate container, and the connecting seats are all made of insulating material.

[0012] Optionally, the plurality of connecting seats are all made of organic glass or bakelite.

[0013] Optionally, the electrode pair is made of red copper, and the symmetrical inner surfaces of the electrode pair are provided with a silver-plated layer.

[0014] Optionally, a first pressure detection device is provided between the intermediate container and the connecting seat.

[0015] Optionally, a second pressure detection device is provided between the clamp and the hand pump.

[0016] Optionally, the flat core oil saturation joint measurement device further includes a liquid storage tank, the liquid storage tank is connected to the intermediate container, and a horizontal flow pump is provided between the liquid storage tank and the intermediate container.

[0017] Optionally, two intermediate containers are provided, the simulated water and the simulated oil are respectively contained in the two intermediate containers, the inlets of the two intermediate containers are connected to the liquid storage tank via a first three-way valve, and the outlets of the two intermediate containers are connected to the connecting seat via a second three-way valve.

[0018] The present invention also provides a method for testing the oil saturation of a flat core. According to the device for testing the oil saturation of a flat core provided in any of the above embodiments, the method for testing the oil saturation of a flat core comprises the following steps:

[0019] S1, taking a flat core and weighing it; placing the weighed flat core in a holder, evacuating the flat core, injecting simulated water into the flat core until saturated, weighing the flat core again, and calculating the pore volume of the flat core;

[0020] S2, injecting simulated oil into the flat core until saturated, and measuring the resistivity of each electrode pair of the flat core;

[0021] S3, using the simulated water to displace the simulated oil in the flat core, and stopping the displacement when the water content in the discharged liquid reaches a set value; detecting the resistivity of the electrode pair, the content of the simulated water, and the content of the simulated oil during the displacement process;

[0022] S4, drawing the oil saturation field curve of the flat core at different stages according to the resistivity and the nuclear magnetic resonance data of the nuclear magnetic resonance device.

[0023] Beneficial effects of the present invention:

[0024] The flat core oil saturation joint measurement device of the present invention, by setting the flat core in a high-temperature and high-pressure reactor, and placing the high-temperature and high-pressure reactor in a nuclear magnetic resonance device, uses simulated oil and simulated water to perform a saturation displacement test on the flat core, can test the fluctuation of the saturation field in the flat core under real high-temperature and high-pressure reservoir conditions, can test the irregular flow field formed by the constantly changing fluid in the flat core, and can calculate the accurate oil saturation field by collecting resistivity and nuclear magnetic resonance data at different stages.

[0025] The method for testing the oil saturation of a flat core of the present invention first calculates the pore volume of the flat core by saturating it with simulated water; then, through the process of saturating the simulated oil and displacing the simulated oil with simulated water, the resistivity of the electrode pair on the flat core is used to collect the nuclear magnetic resonance data of the nuclear magnetic resonance device, and then the oil saturation field curves of the flat core at different stages are drawn, so as to realize the accurate testing of the oil saturation of the flat core. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of a device for measuring oil saturation of a flat core provided by an embodiment of the present invention;

[0027] Figure 2 It is a distribution diagram of the oil saturation field obtained by the flat plate core oil saturation testing method provided in an embodiment of the present invention.

[0028] In the figure:

[0029] 100, flat core; 101, connecting seat;

[0030] 1. Clamp; 2. High temperature and high pressure reactor; 3. Nuclear magnetic resonance device; 4. Constant temperature box; 5. Intermediate container; 51. First pressure detection device; 52. First three-way valve; 53. Second three-way valve; 6. Oil and water metering device; 7. Resistivity monitoring device; 71. Wire row; 8. Hand pump; 81. Second pressure detection device; 9. Liquid storage tank; 91. Horizontal flow pump; 10. Computer. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0032] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0035] The embodiment of the present invention provides a device for measuring oil saturation of a flat core. Figure 1As shown, it includes a holder 1, a high temperature and high pressure reactor 2, a nuclear magnetic resonance device 3, a thermostat 4 and a hand pump 8, wherein a flat core 100 is arranged in the holder 1, the holder 1 is placed in the high temperature and high pressure reactor 2, and the high temperature and high pressure reactor 2 is located in the nuclear magnetic resonance device 3; a plurality of connecting seats 101 are arranged at the upper end of the flat core 100, and a plurality of electrode pairs are arranged inside, and at least one connecting seat 101 among the plurality of connecting seats 101 is connected to an intermediate container 5 so as to facilitate the use of simulated oil or simulated water in the intermediate container 5 to perform a saturated displacement test on the flat core 100, and the remaining connecting seats 101 are all connected to an oil-water metering device 6 so that the oil-water metering device 6 can collect the simulated water content and simulated oil content in the liquid discharged from the flat core 100 during the displacement process. The plurality of electrode pairs are connected to a resistivity monitoring device 7 through a wire row 71 for detecting the resistivity of each electrode pair. The intermediate container 5 is used to hold simulated oil and / or simulated water; the oil-water metering device 6, the intermediate container 5 and the nuclear magnetic resonance device 3 are all arranged in a constant temperature box 4, which can provide constant temperature and pressure to ensure the displacement test conditions. The hand pump 8 is connected to the holder 1 to pressurize the flat core 100 in the holder 1.

[0036] The oil saturation joint measurement device for a flat core of the present invention is provided by placing a flat core 100 in a clamp 1 and then placing it in a high-temperature and high-pressure reactor 2, and placing the high-temperature and high-pressure reactor 2 in a nuclear magnetic resonance device 3, pressurizing the flat core 100 by a hand pump 8 to ensure the pressure environment of the displacement test, and performing a saturation displacement test on the flat core 100 using simulated oil and simulated water. The fluctuation of the saturation field in the flat core 100 under real high-temperature and high-pressure reservoir conditions and the irregular flow field formed by the constantly changing fluid in the flat core 100 can be tested, and the accurate oil saturation field can be calculated by collecting the resistivity and nuclear magnetic resonance data of the electrode pairs at different stages, thereby realizing accurate measurement of the oil saturation of the flat core.

[0037] It should be supplemented that, in order to facilitate connection, a flow port is provided on the high-temperature and high-pressure reactor 2 to facilitate the connection of the connecting seat 101 and the electrode on the flat core 100 to the outside world. In this embodiment, there are nine connecting seats 101, which are arranged in three rows and three columns, so as to facilitate the use of the reverse nine-point method for displacement test. The middle connecting seat 101 is connected to the intermediate container 5 to inject simulated water or simulated oil into the flat core 100, and the remaining connecting seats 101 are all connected to the oil-water metering device 6 to facilitate the flow detection of the liquid discharged by the displacement, including the detection of the simulated oil content and the simulated water content. The connecting seats 101 are all made of insulating materials, such as plexiglass or bakelite.

[0038] Optionally, epoxy resin is coated on the outer side of the flat core 100. Coating the flat core 100 with epoxy resin is beneficial to improving the calculation accuracy of the pore volume.

[0039] Optionally, the electrode pair is made of red copper, and the symmetrical inner surfaces of the electrode pair are provided with a silver-plated layer to improve the conductivity.

[0040] Optionally, a first pressure detection device 51 is provided between the intermediate container 5 and the connecting seat 101 to detect the pressure of the injected simulated water or simulated oil. The first pressure detection device 51 is a pressure gauge.

[0041] Optionally, a second pressure detection device 81 is provided between the holder 1 and the hand pump 8. The second pressure detection device 81 is a pressure gauge, which is used to detect the pressure of the gas added into the holder 1 to ensure the test pressure of the flat core 100 and provide different test pressures.

[0042] Optionally, the flat core oil saturation joint measurement device further includes a liquid storage tank 9 , which is connected to the intermediate container 5 , and a horizontal flow pump 91 is provided between the liquid storage tank 9 and the intermediate container 5 .

[0043] like Figure 1 As shown, since the intermediate container 5 is arranged in the thermostat 4 and has a limited volume, when the amount of simulated oil or simulated water required for the displacement test exceeds the capacity of the intermediate container 5, it needs to be supplemented through the liquid storage tank 9, and the simulated oil or simulated water in the liquid storage tank 9 is supplemented to the intermediate container 5 through the horizontal flow pump 91, so as to carry out continuous tests, which is conducive to improving the test efficiency. It should be noted that the temperature of the liquid in the liquid storage tank 9 needs to be the same as the temperature in the thermostat 4 to avoid temperature changes affecting the test effect.

[0044] Optionally, two intermediate containers 5 are provided, and the two intermediate containers 5 contain simulated water and simulated oil respectively. The inlets of the two intermediate containers 5 are connected to the liquid storage tank 9 through the first three-way valve 52, and the outlets of the two intermediate containers 5 are connected to the connecting seat 101 through the second three-way valve 53.

[0045] like Figure 1 , the three ports of the first three-way valve 52 are respectively connected to the liquid storage tank 9 and the two intermediate containers 5, and the two intermediate containers 5 are respectively filled with simulated oil and simulated water. When the test requires other liquids, an intermediate container 5 can be added. Of course, if the volume of the thermostat 4 is sufficient, the amount of simulated oil and simulated water can also be increased by adding intermediate containers 5 to ensure that the entire test is completed in the thermostat 4 to ensure the constant temperature effect. The three ports of the second three-way valve 53 are respectively connected to the two intermediate containers 5 and a connecting seat 101 on the flat core 100, which is used to selectively inject simulated oil or simulated water into the flat core 100. In some embodiments, the first three-way valve 52 and the second three-way valve 53 are both electric valves for automatic control.

[0046] It should be noted that the flat core oil saturation joint measurement device also includes a computer 10, and the nuclear magnetic resonance device 3 and the resistivity monitoring device 7 are both connected to the computer 10 to facilitate real-time collection of test data for real-time calculation, which is beneficial to monitoring the test process and improving calculation efficiency.

[0047] The present invention also provides a method for testing the oil saturation of a flat core. According to the device for testing the oil saturation of a flat core provided by the above embodiment, the method for testing the oil saturation of a flat core comprises the following steps:

[0048] S1, taking the flat core 100 and weighing it; placing the weighed flat core 100 in the holder 1, evacuating the flat core 100 and saturating it with simulated water, weighing the flat core 100 again, and calculating the pore volume of the flat core 100;

[0049] The flat core oil saturation test method provided in this embodiment adopts the inverse nine-point method, the test temperature is 45°C, and the test pressure is 2Mpa. The outer side of the flat core 100 includes epoxy resin, and the permeability is 532×10 -3 μm 2 . The vacuuming of the flat core 100 in the holder 1 can be achieved by connecting a vacuuming device to the holder 1. During the vacuuming process, the holder 1 is first vacuumed continuously for 3-4 hours, and when the pressure reaches -0.1MPa, the vacuuming is continued for 48 hours to ensure the vacuum effect. Then, the simulated water saturation operation is performed on the flat core 100 through the intermediate container 5. It is generally known in the art to calculate the void volume of the flat core 100 based on the weight difference before and after the flat core 100 and the density of the simulated water, which will not be described in detail herein.

[0050] S2, saturating the flat core 100 with simulated oil and measuring the resistivity of each electrode pair of the flat core 100;

[0051] The simulated oil used in this embodiment is a mixture of dehydrated crude oil from the oil field and kerosene in a volume ratio of 5:1, with a viscosity of 12mPa·s (45°C). The simulated oil and simulated water are respectively loaded into two intermediate containers 5. The simulated water and simulated oil used in the experiment are also respectively loaded into two liquid storage tanks 9 to provide sufficient simulated water and simulated oil. During the experiment, the simulated oil and simulated water in the liquid storage tank 9 are pumped into the two intermediate containers 5 by the horizontal flow pump 91 for replenishment. The liquid storage tank 9 is placed in a constant temperature water bath at 45°C, and the temperature in the thermostat 4 is 45°C. The liquid storage tank 9 continuously stirs the simulated water during the experiment, and the speed of the stirrer is 360r / min. When the flat core 100 is saturated with simulated oil, the flow rate of the simulated oil is 0.5mL / min. The resistivity of the electrode pair is collected in real time during the saturated simulated oil process.

[0052] S3, using simulated water to displace simulated oil on the flat core 100, and stopping the displacement when the water content in the discharged liquid reaches a set value; detecting the resistivity of the electrode pair, the content of simulated water, and the content of simulated oil during the displacement process;

[0053] Typically, the flooding can be stopped when the water content reaches 98%.

[0054] S4, drawing the oil saturation field curve of the flat core 100 at different stages according to the resistivity and the nuclear magnetic resonance data of the nuclear magnetic resonance device 3.

[0055] Through the displacement test process of the flat core 100 with a porosity of 22.1%, the oil saturation field obtained during the test is as follows: Figure 2 As shown, dark colors indicate locations with higher oil saturation, and light colors indicate locations with lower oil saturation. The contour lines of the oil saturation field conform to the characteristics of water-driven oil displacement, proving that the data measured by the flat core oil saturation test method meets the test requirements and satisfies the calculation accuracy. The variation law of the oil saturation field obtained through the flat core displacement test can guide the on-site production of the oil field. By changing parameters such as the injection rate and injection volume, comparative tests can be carried out to compare the advantages of different production systems.

[0056] The method for testing the oil saturation of the flat core of the present invention first calculates the pore volume of the flat core 100 by saturating it with simulated water; then, through the process of saturating the simulated oil and displacing the simulated oil with simulated water, the resistivity of the electrode pair on the flat core 100 is used to collect the nuclear magnetic resonance data of the nuclear magnetic resonance device 3, and then the oil saturation field curves of the flat core 100 at different stages are drawn to achieve accurate testing of the oil saturation of the flat core.

[0057] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A device for measuring oil saturation in a flat core, characterized in that: include: A holder (1), a flat core (100) is arranged in the holder (1), a plurality of connecting seats (101) are arranged at the upper end of the flat core (100), a plurality of electrode pairs are arranged inside the flat core (100), at least one of the connecting seats (101) is connected to an intermediate container (5), and the remaining connecting seats (101) are all connected to an oil-water metering device (6), the plurality of electrode pairs are connected to a resistivity monitoring device (7) via a wire row (71), and the intermediate container (5) is used to contain simulated oil or simulated water; A high-temperature and high-pressure reactor (2), wherein the holder (1) is placed in the high-temperature and high-pressure reactor (2); A nuclear magnetic resonance device (3), wherein the high temperature and high pressure reaction vessel (2) is located inside the nuclear magnetic resonance device (3); A constant temperature box (4), wherein the oil-water metering device (6), the intermediate container (5) and the nuclear magnetic resonance device (3) are all arranged in the constant temperature box (4); A hand pump (8) is connected to the holder (1) to pressurize the flat core (100).

2. The device for measuring oil saturation of a flat core according to claim 1, characterized in that: The outer side of the flat core (100) is coated with epoxy resin.

3. The device for measuring oil saturation of a flat core according to claim 1, characterized in that: There are nine connecting seats (101) arranged in three rows and three columns. The connecting seat (101) in the middle is connected to the intermediate container (5). The connecting seats (101) are all made of insulating material.

4. The device for measuring oil saturation of a flat core according to claim 3, characterized in that: The plurality of connecting seats (101) are all made of organic glass or bakelite.

5. The device for measuring oil saturation of a flat core according to claim 1, characterized in that: The electrode pair is made of red copper, and the symmetrical inner surfaces of the electrode pair are provided with a silver-plated layer.

6. The device for measuring oil saturation of a flat core according to claim 1, characterized in that: A first pressure detection device (51) is provided between the intermediate container (5) and the connecting seat (101).

7. The device for measuring oil saturation of a flat core according to claim 1, characterized in that: A second pressure detection device (81) is provided between the clamp (1) and the hand pump (8).

8. The device for measuring oil saturation of a flat core according to claim 1, characterized in that: It also comprises a liquid storage tank (9), the liquid storage tank (9) is connected to the intermediate container (5), and a horizontal flow pump (91) is provided between the liquid storage tank (9) and the intermediate container (5).

9. The device for measuring oil saturation of a flat core according to claim 8, characterized in that: Two intermediate containers (5) are provided, and the simulated water and the simulated oil are respectively contained in the two intermediate containers (5); the inlets of the two intermediate containers (5) are connected to the liquid storage tank (9) via a first three-way valve (52); and the outlets of the two intermediate containers (5) are connected to the connecting seat (101) via a second three-way valve (53).

10. A method for testing the oil saturation of a flat core, characterized in that: According to the device for measuring oil saturation of a flat core according to any one of claims 1 to 9, the method for measuring oil saturation of a flat core comprises the following steps: S1, taking a flat core (100) and weighing it; placing the weighed flat core (100) in a holder (1), evacuating the flat core (100) and injecting simulated water into the flat core (100) until saturation; weighing the flat core (100) again, and calculating the pore volume of the flat core (100); S2, injecting simulated oil into the flat core (100) until saturation, and measuring the resistivity of each electrode pair of the flat core (100); S3, using the simulated water to displace the simulated oil in the flat core (100), and stopping the displacement when the water content in the discharged liquid reaches a set value; and detecting the resistivity of the electrode pair, the content of the simulated water, and the content of the simulated oil during the displacement process; S4, drawing the oil saturation field curve of the flat core (100) at different stages according to the resistivity and the nuclear magnetic resonance data of the nuclear magnetic resonance device (3).

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