A displacement replacement perturbation simulation system and method

Abstract

A displacement replacement perturbation simulation system and method, which relate to the field of displacement. The displacement replacement perturbation simulation system and method inject water and displacement fluid into a core clamped by a core clamping system through a fluid injection system after pressurization and preheating through a fluid injection pipe in sequence for water saturation and displacement operations, and adjust the gas-liquid fluid discharged from the core to a preset pressure through a fluid discharge pipe and discharge it to a backpressure control monitoring and metering system for gas-liquid separation, and respectively detect the volume, temperature and pressure of the gas phase and liquid phase after gas-liquid separation, and then calculate the final injection volume of the displacement fluid, the cumulative gas production volume and the cumulative water production volume, so as to carry out high-temperature, high-pressure and large-flow displacement injection tests on large-sized cores to explore the physical processes of gas flooding and gas displacement in deep reservoirs.

Description

Technical Field

[0001] This application relates to the field of displacement, and more particularly, to a displacement replacement perturbation simulation system and method. Background Art

[0002] As an effective means to increase the production of oil, coalbed methane, and shale gas and to achieve geological sequestration of carbon dioxide, gas displacement technology has received extensive attention and research. However, the application of gas displacement technology is still not widespread at present, and people's understanding of the displacement replacement process is still insufficient. To meet the high-pressure loading requirements, existing displacement experimental devices are mainly designed for small-sized cores, and usually use cylinders with dimensions of 25×50mm, 50×100mm or cube cores with a side length of 300mm for experiments. These smaller core sizes often correspond to smaller pore volumes, making it easier to inject and control gas. At the same time, due to the small core size, existing displacement experiments are often carried out on the entire end face of the core, and it is impossible to achieve precise displacement of specific areas, which is quite different from the actual production situation of oil and gas fields. Moreover, existing displacement methods mainly include constant-pressure injection, constant-flow injection, or cyclic injection. These displacement methods do not consider the formation of preferential flow channels during the displacement process and cannot adjust the displacement scheme according to the actual displacement situation, resulting in low displacement efficiency and poor results. Summary of the Invention

[0003] The purpose of this application is to provide a displacement replacement perturbation simulation system and method, which can carry out high-temperature, high-pressure and large-flow displacement injection experiments on large-sized cores to explore the physical processes of gas displacing oil and gas in deep reservoirs, and obtain accurate final injection amounts of displacement fluids, gas-phase cumulative production amounts, and water-phase cumulative production amounts.

[0004] This application is implemented as follows:

[0005] This application provides a displacement replacement perturbation simulation system, including:

[0006] At least one fluid injection system, the fluid injection system includes a gas cylinder, a gas booster, a pressure-resistant container, and a first piston pump connected in sequence through pipelines;

[0007] A fluid injection pipe, connected to the first piston pump of each fluid injection system, and a first back pressure controller, a preheater, and a first pressure sensor are sequentially provided on the fluid injection pipe;

[0008] Core clamping system, comprising two end pads for pressing against and clamping both ends of a core, with a plurality of displacement regions provided on the end pads. Each displacement region includes a displacement hole provided on the end pad, a plurality of annular displacement channels sleeved outside the displacement hole, and a plurality of radial displacement channels extending radially along the displacement hole. Each radial displacement channel communicates with the displacement hole and each corresponding annular displacement channel; fluid injection pipes are respectively connected to the displacement holes of one end pad through pipes provided with first connection valves;

[0009] Fluid discharge pipe, which is respectively connected to the displacement holes of the other end pad through pipes provided with second connection valves, and a second pressure sensor is provided on the fluid discharge pipe;

[0010] Back pressure control monitoring and metering system, comprising a second back pressure controller connected to the fluid discharge pipe, a gas-liquid separation device connected to the second back pressure controller, a gas metering device and a second plunger pump respectively connected to the gas-liquid separation device, and a camera device for collecting the liquid level image in the gas-liquid separation device. The gas metering device is connected with a gas component detection device.

[0011] In some alternative embodiments, at least one fluid injection system includes a refrigerating water bath device for adjusting the temperatures of the corresponding pressure-resistant container and the first plunger pump to 0 - 25 degrees.

[0012] In some alternative embodiments, at least one fluid injection system includes a piston container, and the piston container is connected to the outlet of the corresponding first plunger pump through a pipe provided with a container control valve.

[0013] In some alternative embodiments, a first control valve is provided in the pipe between the gas cylinder and the gas booster, and / or a second control valve is provided in the pipe between the gas booster and the pressure-resistant container.

[0014] In some alternative embodiments, a third control valve is provided in the pipe connected to the inlet of the first plunger pump, and / or a fourth control valve is provided in the pipe connected to the outlet of the first plunger pump.

[0015] In some alternative embodiments, the core clamping system further includes at least one intermediate pipe, both ends of the intermediate pipe are respectively connected to the fluid injection pipe and the fluid discharge pipe, and a fifth control valve, a differential pressure gauge and a sixth control valve are provided on the intermediate pipe.

[0016] This application also provides a displacement replacement disturbance simulation method, which includes the following steps:

[0017] After pressing two end pads against both ends of the core respectively, clamp and fix them. There are multiple displacement areas on the end pads. Each displacement area includes displacement holes provided on the end pads, multiple annular displacement channels sleeved outside the displacement holes, and multiple radial displacement channels extending radially along the displacement holes. Each radial displacement channel communicates with the displacement hole and each corresponding annular displacement channel;

[0018] Adjust the water to the preset temperature and pressure, and then introduce it into each displacement hole of one end pad to saturate the core with water;

[0019] Use the first plunger pump to adjust the displacement fluid to the preset pressure and then uniformly introduce it into each displacement hole of one end pad, and uniformly discharge the gas-liquid mixture fluid in each displacement hole of the other end pad and then transport it through the second back pressure controller for gas-liquid separation, and detect the volumes of the gas phase and liquid phase of the gas-liquid separation respectively;

[0020] Perform correction calculations on the injection amount of the displacement fluid, the gas production amount and the liquid production amount of the gas-liquid separation respectively to obtain the final injection amount of the displacement fluid, the cumulative gas production amount and the cumulative water production amount.

[0021] In some alternative embodiments, after adjusting the displacement fluid to the preset temperature and pressure, introduce it uniformly into each displacement hole of one end pad according to the following formula:

[0022]

[0023] In the formula, k i is the number of each displacement hole into which the displacement fluid is introduced. When F i is 0, it means to stop injecting the displacement fluid into the corresponding displacement hole. When F i is 1, it means to inject the displacement fluid into the corresponding displacement hole. The injection and stop injection of the displacement fluid in each displacement hole are controlled by valves; I(k i ) is the corresponding resistivity at the 1 / 4 depth projection of the end face inside the core injection fluid end of each displacement hole;

[0024] And / or, discharge the gas-liquid mixture fluid in each displacement hole of the other end pad uniformly according to the following formula for gas-liquid separation:

[0025]

[0026] In the formula, k j is the number of each displacement hole for discharging the gas-liquid mixture fluid. When F j is 0, it means to stop discharging the gas-liquid mixture fluid from the corresponding displacement hole. When F j is 1, it means to discharge the gas-liquid mixture fluid from the corresponding displacement hole. The discharge and stop discharge of the gas-liquid mixture fluid in each displacement hole are controlled by valves; I(k j) is the corresponding resistivity at the 1 / 4 depth projection inside the end face of each displacement hole at the fluid discharge end of the core.

[0027] In some alternative embodiments, the following formula is used for the correction calculation of the injection volume of the displacement fluid to obtain the final injection volume of the displacement fluid:

[0028]

[0029] In the formula, p inj is the injection pressure of the first plunger pump for injecting the displacement fluid into each displacement hole; p1 is the final pressure when the displacement fluid is injected into each displacement hole; ΔV pump is the cumulative change in the volume of the displacement fluid in the first plunger pump during the process of injecting the displacement fluid into each displacement hole; V u (dead) is the pipeline volume between the first plunger pump and each displacement hole for injecting the displacement fluid; Z inj is the compressibility of the fluid in the first plunger pump; Z1 is the compressibility of the fluid in the pipeline between the first plunger pump and each displacement hole for injecting the displacement fluid; T inj is the temperature of the fluid in the first plunger pump; T1 is the temperature of the fluid in the pipeline between the first plunger pump and each displacement hole for injecting the displacement fluid.

[0030] In some alternative embodiments, the following formula is used for the correction calculation of the gas-phase output of gas-liquid separation to obtain the cumulative gas-phase output:

[0031] Pro(water) = V water -V u (dead)-V d (dead);

[0032] In the formula, V water is the liquid production volume detected for the liquid phase volume of gas-liquid separation under atmospheric pressure; V u (dead) is the pipeline volume between the first plunger pump and each displacement hole for injecting the displacement fluid; V d (dead) is the volume of the pipeline between each displacement hole for discharging the gas-liquid mixed fluid and the second back pressure controller;

[0033] The following formula is used for the correction calculation of the liquid-phase output of gas-liquid separation to obtain the cumulative water-phase output:

[0034]

[0035] In the formula, V gasThe gas production volume is obtained by detecting the gas phase volume of gas-liquid separation under atmospheric pressure; p0 is the atmospheric pressure; p2 is the pressure in the pipeline between each displacement hole discharging the gas-liquid mixed fluid and the second back pressure controller; Z0 is the compressibility of the fluid under atmospheric pressure; Z2 is the compressibility of the fluid in the pipeline between each displacement hole discharging the gas-liquid mixed fluid and the second back pressure controller; T0 is the temperature of the fluid under atmospheric pressure; T2 is the temperature of the fluid in the pipeline between each displacement hole discharging the gas-liquid mixed fluid and the second back pressure controller.

[0036] The beneficial effects of this application are as follows: The displacement replacement perturbation simulation system and method provided by this application inject water and displacement fluid into the core clamped by the core clamping system through the fluid injection system after pressurization and preheating through the fluid injection pipe in sequence for water saturation and displacement operations, and adjust the gas-liquid fluid discharged from the core to a preset pressure through the fluid discharge pipe and discharge it to the back pressure control monitoring and metering system for gas-liquid separation. After detecting the volume, temperature, and pressure of the gas phase and liquid phase after gas-liquid separation respectively, the final injection volume of the displacement fluid, the cumulative gas production volume, and the cumulative water production volume are calculated, so that high-temperature, high-pressure, and large-flow displacement injection tests of large-sized cores can be carried out to explore the physical processes of gas flooding and gas displacement in deep reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of this application, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of this application, so they should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0038] Figure 1 It is a schematic structural diagram of the displacement replacement perturbation simulation system provided by the embodiment of this application;

[0039] Figure 2 It is a schematic structural diagram of the end plate in the displacement replacement perturbation simulation system provided by the embodiment of this application;

[0040] Figure 3 is Figure 2 the partial enlarged structural diagram at A in

[0041] Figure 4 It is a schematic structural diagram of arranging water saturation measurement points inside the core in the displacement replacement perturbation simulation method provided by the embodiment of this application;

[0042] Figure 5 It is a schematic structural diagram of the displacement replacement perturbation simulation system provided by another embodiment of this application.

[0043] In the figure: 100, fluid injection system; 110, gas cylinder; 120, gas booster; 130, pressure-resistant container; 140, first plunger pump; 150, refrigerating water bath device; 160, piston container; 170, container control valve; 180, first control valve; 190, second control valve; 191, third control valve; 192, fourth control valve; 200, fluid injection pipe; 210, first back pressure controller; 220, preheater; 230, first pressure sensor; 240, first connection valve; 250, fluid discharge pipe; 260, second connection valve; 270, second pressure sensor; 300, core clamping system; 310, end pad; 311, displacement area; 312, displacement hole; 313, annular displacement channel; 314, radial displacement channel; 320, intermediate pipe; 330, fifth control valve; 340, differential pressure gauge; 350, sixth control valve; 400, back pressure control monitoring and metering system; 410, second back pressure controller; 420, gas-liquid separation device; 430, gas metering device; 440, second plunger pump; 450, camera device; 460, gas component detection device; 500, core. Detailed implementation manners

[0044] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. Generally, the components of the embodiments of the present application described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0046] It should be noted that: like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0047] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of this application is usually placed during use. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present application. In addition, terms such as "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0048] In addition, terms such as "horizontal", "vertical", "hanging", etc. do not mean that the components are required to be absolutely horizontal or hanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0049] In the description of the present application, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "connected" 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 directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0050] In the present application, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0051] The features and performance of the displacement replacement perturbation simulation system and method of the present application will be further described in detail below in conjunction with embodiments.

[0052] Such as Figure 1 、 Figure 2 、 Figure 3As shown in the figure, an embodiment of the present application provides a displacement replacement perturbation simulation system, including two fluid injection systems 100, a fluid injection pipe 200, a core clamping system 300, a fluid discharge pipe 250, and a back pressure control monitoring and metering system 400;

[0053] Among them, each of the two fluid injection systems 100 includes a gas cylinder 110, a gas booster 120, a pressure-resistant container 130, and a first plunger pump 140 connected in sequence through pipelines. A first control valve 180 is provided in the pipeline between the gas cylinder 110 and the gas booster 120 in each fluid injection system 100. A second control valve 190 is provided in the pipeline between the gas booster 120 and the pressure-resistant container 130 in each fluid injection system 100. A third control valve 191 and a fourth control valve 192 are respectively provided in the pipelines connecting the inlet and outlet of the first plunger pump 140 in each fluid injection system 100. One fluid injection system 100 further includes a refrigerated water bath device 150, and the refrigerated water bath device 150 is used to adjust the temperatures of the corresponding pressure-resistant container 130 and the first plunger pump 140 to 0 - 25 degrees. The other fluid injection system 100 further includes a piston container 160, and the piston container 160 is connected to the outlet of the corresponding first plunger pump 140 through a pipeline provided with a container control valve 170. The gas booster 120 is used to increase the fluid pressure and then output it. In this embodiment, the gas booster 120 can increase the fluid pressure to 40 Mpa and then output it. The plunger pump is designed with a double pump, the single pump cavity volume is 300 ml, the maximum flow rate is 180 ml / min, and the maximum injection pressure is 70 MPa. The volume of the pressure-resistant container 130 is 5 L, and the pressure resistance is 70 MPa, which is used to provide a stable gas source for high-pressure fluid injection. The volume of the piston container 160 is 3 L, the material is 2205 high-strength stainless steel, and the pressure resistance is 70 MPa, which can realize the injection of gas, water, and weakly corrosive media (such as hydrochloric acid, hydrofluoric acid, and acetic acid, etc.). The back pressure controller is used to control the pressure of the flowing fluid, and the maximum control pressure is 70 MPa.

[0054] One end of the fluid injection pipe 200 is respectively communicated with the outlet of the first plunger pump 140 of each fluid injection system 100. A first back pressure controller 210, a preheater 220, and a first pressure sensor 230 are sequentially provided on the fluid injection pipe 200 as it moves away from the fluid injection system 100. The preheater 220 is used to heat the flowing fluid to 10 - 200 degrees Celsius.

[0055] The core clamping system 300 includes two end pads 310 for pressing and clamping both ends of the core 500. The end pads 310 are square, and one side surface facing the core 500 is provided with four square displacement regions 311. A displacement hole 312 provided on the end pad 310 is provided at the center of each displacement region 311. Each displacement region 311 is further respectively provided with an annular displacement channel 313 sleeved outside the displacement hole 312 and arranged at intervals in the radial direction of the displacement hole 312, and six radial displacement channels 314 extending in the radial direction of the displacement hole 312. The six radial displacement channels 314 are arranged at intervals in the circumferential direction of the displacement hole 312. Each radial displacement channel 314 communicates with the displacement hole 312 and each corresponding annular displacement channel 313; the other ends of the fluid injection pipes 200 are respectively communicated with the displacement holes 312 of one end pad 310 through pipes provided with first connection valves 240; the core clamping system 300 further includes three intermediate pipes 320. The two ends of the intermediate pipes 320 are respectively connected to the fluid injection pipes 200 and the fluid discharge pipes 250 through three-way interfaces. A fifth control valve 330, a differential pressure gauge 340, and a sixth control valve 350 are provided on the intermediate pipes 320.

[0056] One end of the fluid discharge pipe 250 is respectively communicated with the displacement holes 312 of the other end pad 310 through pipes provided with second connection valves 260. A second pressure sensor 270 is provided on the fluid discharge pipe 250;

[0057] The back pressure control monitoring and metering system 400 includes a second back pressure controller 410 connected to the other end of the fluid discharge pipe 250 through a pipe, a gas-liquid separation device 420 connected to the second back pressure controller 410 through a pipe, a gas metering device 430 and a second plunger pump 440 respectively connected to the gas-liquid separation device 420 through pipes, and a camera device 450 for collecting the liquid level image in the gas-liquid separation device 420. The gas metering device 430 is connected with a gas component detection device 460 through a pipe.

[0058] The embodiment of the present application further provides a displacement replacement disturbance simulation method, which is carried out by using the above displacement replacement disturbance simulation device, and includes the following steps:

[0059] Step 1, as Figure 4As shown, the core is cut into a cube of 800mm×800mm×800mm for testing. A three-dimensional coordinate system is established with the center of the bottom surface of the core as the origin. Two groups of water saturation measurement points are arranged in the core. The first group of water saturation measurement points are K1-1, K2-1, K3-1, and K4-1, and the coordinates of the first group of water saturation measurement points are (-200mm, -200mm, 600mm), (200mm, -200mm, 600mm), (-200mm, -200mm, 200mm), and (200mm, -200mm, 200mm) respectively. The second group of water saturation measurement points are K1-2, K2-2, K3-2, and K4-2, and their coordinates are (-200mm, 200mm, 600mm), (200mm, 200mm, 600mm), (-200mm, 200mm, 200mm), and (200mm, 200mm, 200mm) respectively; Assemble the displacement replacement disturbance simulation device, and press the two end pads 310 against both ends of the core 500 for clamping and fixing respectively, so that the projections of the four displacement holes 312 on the end pad 310 where the displacement fluid is introduced on the end face of one end of the core, i.e., the injection fluid end face, fall on K1-1, K2-1, K3-1, and K4-1 respectively, and the projections of the four displacement holes 312 on the end pad 310 where the gas-liquid mixed fluid is discharged on the end face of the other end of the core, i.e., the discharge fluid end face, fall on K1-2, K2-2, K3-2, and K4-2 respectively;

[0060] Step 2: Adjust the output pressure of the fluid by the first back pressure controller 210 on the fluid injection pipe 200 and the heating temperature of the preheater 220, and adjust the output pressure of the fluid at the outlet by the second back pressure controller 410 in the back pressure control monitoring and metering system 400; Inject water into the piston container 160, control the opening of the container control valve 170 and the fourth control valve 192 in the corresponding fluid injection system 100, control the opening of each first connection valve 240, and use the first plunger pump 140 in the fluid injection system 100 where the piston container 160 is located to adjust the water in the piston container 160 to the preset pressure through the first back pressure controller 210 and heat it to the preset temperature by the preheater 220, and then introduce it into each displacement hole 312 of one end pad 310 to saturate the core 500. After saturation, close the container control valve 170 and the fourth control valve 192;

[0061] Step 3: Adjust the refrigerating water bath temperature of the refrigerating water bath device 150 to 5 °C. Open the gas cylinder 110, the first control valve 180, the second control valve 190, and the third control valve 191 in the fluid injection system 100 where the refrigerating water bath device 150 is located, so that the liquid carbon dioxide in the gas cylinder 110 enters the pressure-resistant container 130 for storage after being pressurized by the gas booster 120 and is introduced into the first plunger pump 140. Subsequently, control the fourth control valve 192, so that the first plunger pump 140 adjusts the carbon dioxide fluid to the preset pressure and temperature through the first back pressure controller 210 and the preheater 220 and then uniformly introduces it into each displacement hole 312 of one end plate 310, and uniformly discharges the gas-liquid mixed fluid in each displacement hole 312 of the other end plate 310 and conveys it to the gas-liquid separation device 420 for gas-liquid separation through the second back pressure controller 410. Use the gas metering device 430 to detect the volume of the gas phase of the gas-liquid separation respectively, and use the imaging device 450 to take pictures of the liquid phase of the gas-liquid separation and identify and detect the volume of the liquid phase;

[0062] Among them, after adjusting the carbon dioxide displacement fluid to the preset temperature and pressure, it is uniformly introduced into each displacement hole 312 of one end plate 310 according to the following formula:

[0063]

[0064] In the formula, k i is the number of each displacement hole 312 into which the displacement fluid is introduced. F i being 0 indicates stopping injecting the displacement fluid into the corresponding displacement hole 312, and F i being 1 indicates injecting the displacement fluid into the corresponding displacement hole 312; I(k i ) is the resistivity at the projection position of 1 / 4 depth inside the rock mass at one end of the core 500 (i.e., the injection fluid end) of each displacement hole 312 (i.e., at K1-1, K2-1, K3-1, and K4-1); I is the resistivity; S w is the water saturation detected at the water saturation measurement point of the projection position of 1 / 4 depth inside the rock mass at one end of the core 500 (i.e., the injection fluid end) of each displacement hole 312 into which the displacement fluid is introduced (i.e., at K1-1, K2-1, K3-1, and K4-1); b and n are parameters; when the resistivities at the projection positions of 1 / 4 depth inside the rock mass at one end of the core 500 (i.e., the injection fluid end) of each displacement hole 312 into which the displacement fluid is introduced are equal, the displacement fluid is injected into each displacement hole 312 simultaneously;

[0065] The gas-liquid mixed fluid in each displacement hole 312 of the other end plate 310 is uniformly discharged for gas-liquid separation according to the following formula:

[0066]

[0067] where k j is the number of each displacement hole 312 for discharging the gas-liquid mixed fluid, and F j being 0 indicates stopping discharging the gas-liquid mixed fluid from the corresponding displacement hole 312, and F j being 1 indicates discharging the gas-liquid mixed fluid from the corresponding displacement hole 312; I(k j ) is the water saturation detected at the water saturation measurement point at the projection of the internal 1 / 4 depth position of the rock mass at the other end of the core 500 (i.e., at K1-2, K2-2, K3-2, and K4-2) of each displacement hole 312 for discharging the gas-liquid mixed fluid; when the resistivity is equal at the projection of the internal 1 / 4 depth position of the rock mass at the other end of the core 500 (i.e., the discharge fluid end) of each displacement hole 312 for discharging the gas-liquid mixed fluid, the gas-liquid mixed fluid is discharged from each displacement hole 312 simultaneously;

[0068] Step Four: Perform correction calculations on the injection amount of the displacement fluid, the gas production amount and the liquid production amount of gas-liquid separation respectively to obtain the final injection amount of the displacement fluid, the cumulative gas production amount and the cumulative water production amount.

[0069] Among them, the following formula is used when performing correction calculations on the injection amount of the displacement fluid to obtain the final injection amount of the displacement fluid:

[0070]

[0071] where p inj is the injection pressure of the first plunger pump 140 for injecting the displacement fluid into each displacement hole 312; p1 is the final pressure when injecting the displacement fluid into each displacement hole 312; ΔV pump is the cumulative change amount of the volume of the displacement fluid in the first plunger pump 140 during the injection of the displacement fluid; V u (dead) is the pipeline volume between the first plunger pump 140 and each displacement hole 312 for injecting the displacement fluid; Z inj is the compressibility of the fluid in the first plunger pump 140; Z1 is the compressibility of the fluid in the pipeline between the first plunger pump 140 and each displacement hole 312 for injecting the displacement fluid; T inj is the temperature of the fluid in the first plunger pump 140; T1 is the temperature of the fluid in the pipeline between the first plunger pump 140 and each displacement hole 312 for injecting the displacement fluid.

[0072] The following formula is used to perform correction calculations on the gas production amount of gas-liquid separation to obtain the cumulative gas production amount:

[0073] Pro(water) = V water - V u (dead) - V d (dead);

[0074] Wherein, V water is the liquid production obtained by detecting the liquid phase volume of gas-liquid separation under atmospheric pressure; V u (dead) is the pipeline volume between the first plunger pump 140 and each displacement hole 312 for injecting displacement fluid; V d (dead) is the volume of the pipeline between each displacement hole 312 for discharging the gas-liquid mixture fluid and the second back pressure controller 410;

[0075] The cumulative water phase production is obtained by correcting and calculating the liquid phase production of gas-liquid separation according to the following formula:

[0076]

[0077] Wherein, V gas is the gas production obtained by detecting the gas phase volume of gas-liquid separation under atmospheric pressure; p0 is the atmospheric pressure; p2 is the pressure inside the pipeline between each displacement hole 312 for discharging the gas-liquid mixture fluid and the second back pressure controller 410; Z0 is the compressibility of the fluid under atmospheric pressure; Z2 is the compressibility of the fluid inside the pipeline between each displacement hole 312 for discharging the gas-liquid mixture fluid and the second back pressure controller 410; T0 is the temperature of the fluid under atmospheric pressure; T2 is the temperature of the fluid inside the pipeline between each displacement hole 312 for discharging the gas-liquid mixture fluid and the second back pressure controller 410.

[0078] The displacement replacement perturbation simulation device and method provided by the embodiments of the present application inject water and displacement fluid into the core 500 clamped by the core clamping system 300 through the fluid injection system 100 after pressurization and preheating through the fluid injection pipe 200 in sequence to perform water saturation and displacement operations, and adjust the gas-liquid fluid discharged from the core 500 to a preset pressure through the fluid discharge pipe 250 and discharge it to the back pressure control monitoring and metering system 400 for gas-liquid separation, and calculate the final injection volume of the displacement fluid, the cumulative gas production volume and the cumulative water production volume after detecting the volume, temperature and pressure of the gas phase and liquid phase after gas-liquid separation respectively, so as to carry out high-temperature, high-pressure and large-flow displacement injection tests on large-sized cores to explore the physical processes of gas flooding and gas displacement in deep reservoirs; wherein the fluid injection system 100 can provide a stable power source for high-pressure fluid injection through the cooperation of the gas booster 120, the pressure-resistant container 130 and the first plunger pump 140, achieve the goal of stable injection with large flow rate, and realize the temperature control of the displacement fluid through the refrigerating water bath device 150; the core clamping system 300 can realize the uniform injection and discharge functions of displacement fluid in different regions by arranging a plurality of displacement regions 311 on two end pads 310, and each displacement region 311 includes a displacement hole 312 provided on the end pad 310, an annular displacement channel 313 sleeved outside the displacement hole 312 at intervals along the radial direction of the displacement hole 312, and six radial displacement channels 314 extending along the radial direction of the displacement hole 312, so as to simulate the displacement situation of actual reservoir perforation. The back pressure control monitoring and metering system 400 realizes continuous and stable metering of large-flow fluids by combining the visual metering method and the pump suction method through the cooperation of the camera device 450 and the second plunger pump 440. The displacement replacement perturbation simulation device provided by the embodiments of the present application has the advantages of simple structure, reliable design and high detection accuracy, and can simulate the high-temperature and high-pressure displacement conditions of large-sized cores in deep reservoirs.

[0079] The core clamping system 300 includes three intermediate pipes 320. The two ends of the intermediate pipe 320 are respectively connected to the fluid injection pipe 200 and the fluid discharge pipe 250 through three-way interfaces. A fifth control valve 330, a differential pressure gauge 340 and a sixth control valve 350 are arranged on the intermediate pipe 320, and the differential pressure gauge 340 on the intermediate pipe 320 can be used to detect the pressure difference between the displacement holes 312 on the two end pads 310 connected to the fluid injection pipe 200 and the fluid discharge pipe 250 to evaluate the displacement operation situation.

[0080] The displacement replacement perturbation simulation method provided by the embodiments of the present application saturates the core 500 by injecting water into it. Subsequently, after detecting the water saturation by the water saturation measurement points installed at preset positions in the core 500, the conductivity is calculated, and the fluid injection system 100 is controlled according to the conductivity at the preset positions in the core 500. The displacement fluid is uniformly injected into the interior of the core 500, and after displacement, the gas-liquid mixed fluid is uniformly discharged and then gas-liquid separation is carried out. The volume, temperature, and pressure of the gas phase and liquid phase after gas-liquid separation are respectively detected and then corrected calculations are performed to eliminate the errors of the residual fluid in the pipeline, so as to obtain the accurate final injection amount of the displacement fluid, the cumulative gas production amount, and the cumulative water production amount to measure the displacement efficiency, so as to accurately carry out the high-temperature, high-pressure, and large-flow displacement injection test of large-sized cores.

[0081] In other alternative embodiments, such as Figure 5 shown, the displacement replacement perturbation simulation system may also include only one fluid injection system 100. The fluid injection system 100 includes a gas cylinder 110, a gas booster 120, a pressure-resistant container 130, and a first plunger pump 140 connected in sequence through pipelines, and the fluid injection system 100 includes a refrigerated water bath device 150 and a piston container 160 connected to the outlet of the corresponding first plunger pump 140 through a pipeline provided with a container control valve 170.

[0082] The embodiments described above are some embodiments of the present application, rather than all embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application claimed, but merely represents the selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts fall within the scope of protection of the present application.

Claims

1. A displacement replacement perturbation simulation method, characterized in that It is carried out using a displacement replacement perturbation simulation system, and the displacement replacement perturbation simulation system includes: At least one fluid injection system, the fluid injection system includes a gas cylinder, a gas booster, a pressure-resistant container and a first plunger pump connected in sequence through pipelines; A fluid injection pipe, which is communicated with the first plunger pump of each fluid injection system, and a first back pressure controller, a preheater and a first pressure sensor are sequentially arranged on the fluid injection pipe; A core clamping system, which includes two end pads for pressing and clamping both ends of the core, and a plurality of displacement areas are arranged on the end pads. Each displacement area includes a displacement hole arranged on the end pad, a plurality of annular displacement channels sleeved outside the displacement hole, and a plurality of radial displacement channels extending radially along the displacement hole. Each radial displacement channel is communicated with the displacement hole and each corresponding annular displacement channel; the fluid injection pipe is respectively communicated with each displacement hole of one end pad through a pipeline provided with a first connection valve; A fluid discharge pipe, which is respectively communicated with each displacement hole of the other end pad through a pipeline provided with a second connection valve, and a second pressure sensor is arranged on the fluid discharge pipe; A back pressure control monitoring and metering system, which includes a second back pressure controller connected to the fluid discharge pipe, a gas-liquid separation device connected to the second back pressure controller, a gas metering device, a second plunger pump and a camera device for collecting the liquid level image in the gas-liquid separation device respectively connected to the gas-liquid separation device, and the gas metering device is connected with a gas component detection device; The displacement replacement perturbation simulation method includes the following steps: Press and clamp both ends of the core with two end pads respectively, and a plurality of displacement areas are arranged on the end pads. Each displacement area includes a displacement hole arranged on the end pad, a plurality of annular displacement channels sleeved outside the displacement hole, and a plurality of radial displacement channels extending radially along the displacement hole. Each radial displacement channel is communicated with the displacement hole and each corresponding annular displacement channel; Adjust the water to a preset temperature and pressure and then introduce it into each displacement hole of one end pad to saturate the core with water; Use the first plunger pump to adjust the displacement fluid to a preset pressure and then uniformly introduce it into each displacement hole of one end pad, and uniformly discharge the gas-liquid mixed fluid in each displacement hole of the other end pad and then transport it through the second back pressure controller for gas-liquid separation, and respectively detect the volumes of the gas phase and the liquid phase after gas-liquid separation; Respectively perform correction calculations on the injection amount of the displacement fluid, the gas phase output amount and the liquid phase output amount after gas-liquid separation to obtain the final injection amount of the displacement fluid, the cumulative gas phase output amount and the cumulative water phase output amount; when performing the correction calculation on the injection amount of the displacement fluid to obtain the final injection amount of the displacement fluid, the following formula is adopted: ； where p inj is the injection pressure of the first plunger pump for injecting the displacement fluid into each of the displacement holes; p1 is the final pressure when the displacement fluid is injected into each of the displacement holes; is the cumulative change in the volume of the displacement fluid in the first plunger pump during the process of injecting the displacement fluid into each of the displacement holes; is the pipeline volume between the first plunger pump and each of the displacement holes for injecting the displacement fluid; Z inj is the compressibility of the fluid in the first plunger pump; Z 1 is the compressibility of the fluid in the pipeline between the first plunger pump and each of the displacement holes for injecting the displacement fluid; T inj is the temperature of the fluid in the first plunger pump; T 1 is the temperature of the fluid in the pipeline between the first plunger pump and each of the displacement holes for injecting the displacement fluid.

2. The displacement replacement perturbation simulation method according to claim 1, wherein At least one of the fluid injection systems includes a refrigerating water bath device, and the refrigerating water bath device is used to adjust the temperature of the corresponding pressure-resistant container and the first plunger pump to 0-25 degrees.

3. The displacement replacement perturbation simulation method according to claim 1, wherein At least one of the fluid injection systems includes a piston container, and the piston container is connected to the outlet corresponding to the first plunger pump through a pipeline provided with a container control valve.

4. The displacement replacement perturbation simulation method according to claim 1, wherein A first control valve is provided in the pipeline between the gas cylinder and the gas booster, and / or a second control valve is provided in the pipeline between the gas booster and the pressure-resistant container.

5. The displacement replacement perturbation simulation method according to claim 1, characterized in that, A third control valve is provided in the pipeline connected to the inlet of the first plunger pump, and / or a fourth control valve is provided in the pipeline connected to the outlet of the first plunger pump.

6. The displacement replacement perturbation simulation method according to claim 1, wherein The core clamping system further includes at least one intermediate pipe, the two ends of the intermediate pipe are respectively connected to the fluid injection pipe and the fluid discharge pipe, and a fifth control valve, a differential pressure gauge and a sixth control valve are provided on the intermediate pipe.

7. The displacement replacement perturbation simulation method according to claim 1, wherein After adjusting the displacement fluid to a preset temperature and pressure, it is uniformly introduced into each of the displacement holes of one of the end pads according to the following formula: ； Wherein, k i is the number of each of the displacement holes into which the displacement fluid is introduced, F i when it is 0, it means to stop injecting the displacement fluid into the corresponding displacement hole, F i when it is 1, it means to inject the displacement fluid into the corresponding displacement hole, and the injection and stop injection of the displacement fluid in each displacement hole are controlled by a valve; I ( k i ) is the corresponding resistivity at the 1 / 4 depth projection inside the end face of each displacement hole at the fluid injection end of the core; and / or, the gas-liquid mixed fluid in each of the displacement holes of the other end pad is uniformly discharged according to the following formula for gas-liquid separation: ； In the formula, k j is the number of each of the displacement holes for discharging the gas-liquid mixed fluid, F j when it is 0, it means to stop discharging the gas-liquid mixed fluid from the corresponding displacement hole, F j when it is 1, it means to discharge the gas-liquid mixed fluid from the corresponding displacement hole, and the discharge and stop of the gas-liquid mixed fluid in each displacement hole are controlled by a valve; I ( k j ) is the corresponding resistivity at the 1 / 4 depth projection inside the end face of each of the displacement holes at the fluid discharge end of the core.

8. The displacement replacement perturbation simulation method according to claim 1, wherein The gas phase cumulative output is obtained by performing a correction calculation on the gas phase output of the gas-liquid separation according to the following formula: ； Wherein, is the liquid production obtained by detecting the liquid phase volume of gas-liquid separation under atmospheric pressure; is the pipeline volume between the first plunger pump and each of the displacement holes for injecting the displacement fluid; is the volume of the pipeline between each of the displacement holes for discharging the gas-liquid mixed fluid and the second back pressure controller; The aqueous phase cumulative output is obtained by performing a correction calculation on the liquid phase output of the gas-liquid separation according to the following formula: ； In the formula, is the gas production obtained by detecting the gas phase volume of gas-liquid separation under atmospheric pressure; p 0 is the atmospheric pressure; p 2 is the pressure in the pipeline between each of the displacement holes discharging the gas-liquid mixed fluid and the second back pressure controller; Z 0 is the compressibility of the fluid under atmospheric pressure; Z 2 is the compressibility of the fluid in the pipeline between each of the displacement holes discharging the gas-liquid mixed fluid and the second back pressure controller; T 0 is the temperature of the fluid under atmospheric pressure; T 2 is the temperature of the fluid in the pipeline between each of the displacement holes discharging the gas-liquid mixed fluid and the second back pressure controller.

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