Relative permeability curve measuring device and method suitable for multi-round two-phase displacement

Abstract

The invention relates to a relative permeability curve measuring device and method suitable for multi-round two-phase displacement, and the device comprises a measuring system which is used for measuring core parameters; the core holder simulates a gasoline alternating front edge; the injection system is used for simulating a displacement object injection process; the temperature box is used for controlling the temperature of the core holder and the displacement container in the temperature box within a set temperature range; the pressure control system is used for controlling the pressure of the core holder and the injection system within a set voltage range; the data acquisition system is used for detecting and acquiring the pressure change of the front end and the rear end of the core holder during each displacement; the metering system is used for metering the mass and the volume of the output, and the calculation module is used for calculating the relative permeability curve endpoint value according to the core parameters, the pressure change of the front end and the rear end of the core holder during each displacement and the mass and the volume of the output during each displacement. The method adopts the device. According to the invention, multi-round gas-oil mutual drive under high-temperature and high-pressure conditions can be simulated, the success rate of relative permeability curve determination and processing is improved, and accurate and reliable relative permeability data is obtained.

Description

Technical Field

[0001] The present application relates to the technical field of oil and gas extraction, and in particular to a phase permeability curve measurement device and method suitable for multiple rounds of two-phase mutual drive. Background Art

[0002] Gas-oil relative permeability curves are of great value in gas storage management and gas injection to enhance oil recovery. With the global demand for energy growing, optimizing the extraction efficiency of oil and gas resources has become crucial. By describing the flow characteristics of gas and crude oil in oil reservoirs, gas-oil relative permeability curves provide fundamental data for the application of gas injection to enhance oil recovery. Furthermore, the determination of gas-oil relative permeability curves provides a theoretical basis for optimizing gas injection and recovery operations in depleted oil reservoirs.

[0003] Most current research focuses on single-cycle gas-oil displacement processes, while exploration of multiple cycles of mutual displacement is insufficient. Accurately measuring the phase permeability curves for multiple cycles of gas-oil mutual displacement will provide an important theoretical basis for the long-term operation of gas storage facilities and the optimization of gas injection and production. It will also provide basic data for studying the seepage patterns of gas injection and production processes.

[0004] The conventional method for determining the gas-oil phase permeability curve at a constant pressure differential has the following problems: the pressure differential is difficult to control to be constant due to the back-pressure valve's opening pressure and discontinuous gas and oil production. The high gas production rate and short gas-oil two-phase flow time obtained based on the theoretical pressure differential are not conducive to reflecting the impact of core porosity and permeability characteristics on phase permeability. The traditional phase permeability interpretation method is based on the JBN method, which requires very ideal changes in gas and oil production to interpret reasonable phase permeability, which is difficult to achieve with measured data. Even if the measured data is fitted, it may not necessarily interpret a reasonable phase permeability. Summary of the Invention

[0005] Based on this, it is necessary to provide a phase permeability curve measurement device and method suitable for multiple rounds of two-phase mutual drive based on the above technical problems, so as to improve the success rate of its operation and data processing.

[0006] In a first aspect, the present application provides a phase permeability curve measurement device suitable for multiple rounds of two-phase displacement, comprising: A measurement system for obtaining core parameters, including diameter, length, volume, and weight of the core; core holder to simulate the gasoline alternating front; An injection system for simulating a displacement material injection process; the injection system comprises a constant pressure and constant speed pump and a displacement material container connected to the constant pressure and constant speed pump, wherein the displacement material container is connected to a front inlet of the core holder; A temperature box, used to control the temperature of the core holder and the displacement material container placed therein within a set temperature range; a pressure control system, in communication with the core holder, for controlling the pressure of the core holder and the injection system within a set pressure range; A data acquisition system for detecting and collecting pressure changes at the front and rear ends of the core holder during each displacement; a metering system, connected to the rear end outlet of the core holder, for measuring the mass and volume of the output; The calculation module is used to calculate the endpoint value of the phase permeability curve according to the core parameters, the pressure change at the front and rear ends of the core holder during each displacement, and the mass and volume of the output during each displacement.

[0007] In one embodiment, the displacement material container is connected to the front inlet of the core holder through a first six-way valve, and a valve is provided on the passage connecting the front inlet of the core holder and the first six-way valve. In one embodiment, the displacement container comprises: a first displacement material container, connected to the constant pressure and constant speed pump and the first inlet of the first six-way valve, for containing formation crude oil; a second displacement material container, connected to the constant pressure and constant speed pump and the second inlet of the first six-way valve, for containing formation water; a third displacement container, connected to the constant pressure constant speed pump, for containing high-purity methane; the third displacement container is connected to the third inlet of the first six-way valve through a humidifying container for humidifying gas; Each section of the pipeline connecting the displacement material container with the constant pressure and constant speed pump and the first six-way valve is provided with a valve.

[0008] In one embodiment, the pressure control system includes: a first hand pump connected to the confining pressure inlet of the core holder; Gas container for holding high-purity nitrogen; a second hand pump connected to the gas container; a back pressure valve, connecting the rear end outlet of the core holder and the gas container, the back pressure valve being connected to the metering system via a second six-way valve; Valves are provided on the passage connecting the first hand pump and the confining pressure inlet of the core holder, the passage connecting the back pressure valve and the rear end outlet of the core holder, and the passage connecting the back pressure valve and the gas container.

[0009] In one embodiment, the data acquisition system includes a pressure sensor, a first data box connected to the pressure sensor, a differential pressure gauge connected to both ends of the core holder, and a second data box connected to the differential pressure gauge. Both data boxes are connected to a computing module. The first data box is used to collect pressure data detected by the pressure sensor, and the second data box is used to collect differential pressure data detected by the differential pressure gauge. The pressure sensor includes: A first pressure sensor is provided at the front inlet of the core holder and is used to detect the pressure at the front end of the core holder; a second pressure sensor, provided at the confining pressure inlet of the core holder, for detecting the confining pressure of the core holder; a third pressure sensor, provided at the rear end outlet of the core holder, for detecting the rear end pressure of the core holder; The fourth pressure sensor is provided at the outlet of the back pressure valve and is used to detect the back pressure of the core holder.

[0010] In one embodiment, the metering system comprises: a collecting bottle, the collecting bottle being connected to the first outlet of the second six-way valve and being used for storing the produced waste liquid; a first pressure-resistant container assembly comprising a first pressure-resistant container for holding produced crude oil and a third pressure-resistant container for holding a desiccant; the first pressure-resistant container being in communication with the second outlet of the second six-way valve, and the air outlet of the first pressure-resistant container being in communication with the air inlet of the third pressure-resistant container; a first exhaust pipe, connecting the gas outlet of the third pressure-resistant container with the external atmosphere; a second pressure-resistant container assembly comprising a second pressure-resistant container for holding produced crude oil and a fourth pressure-resistant container for holding a desiccant; the second pressure-resistant container is in communication with the third outlet of the second six-way valve, and the air outlet of the second pressure-resistant container is in communication with the air inlet of the fourth pressure-resistant container; the capacity of the second pressure-resistant container is different from that of the first pressure-resistant container; a second exhaust pipe, communicating the gas outlet of the fourth pressure-resistant container with the external atmosphere; The measuring assembly includes a first electronic scale for placing the first pressure-resistant container assembly and a second electronic scale for placing the second pressure-resistant container assembly; The flow meter comprises a first flow meter arranged on the first exhaust pipe and a second flow meter arranged on the second exhaust pipe, wherein the first flow meter and the second flow meter are used to measure the volume of the output high-purity methane.

[0011] In one embodiment, the phase permeability curve measuring device suitable for multiple rounds of two-phase drive further includes a vacuum pump, which is connected in series with the core holder.

[0012] In a second aspect, an embodiment of the present application provides a method for measuring a phase permeability curve applicable to multiple rounds of two-phase flooding, using the phase permeability curve measuring device applicable to multiple rounds of two-phase flooding described in the embodiment of the first aspect of the present application, the method comprising: Using a phase permeability curve measurement device suitable for multiple rounds of two-way flooding, multiple rounds of gas-oil flooding were carried out to obtain the endpoint values of each round's parameters, as well as gas and oil production and pressure data; Correcting the gas and oil outputs of each round to obtain an ideal gas and oil output; Substituting the ideal gas and oil production into the gas-drive-oil core conceptual model and the oil-drive-gas core conceptual model, performing automatic history fitting, and obtaining the optimal morphological index; The optimal morphological index is substituted into the calculation model to obtain the gas-oil mutual drive parameters and the gas-oil mutual drive phase permeability curves of each round.

[0013] In one embodiment, multiple rounds of gas-oil mutual flooding are performed using a phase permeability curve measuring device suitable for multiple rounds of two-way mutual flooding to obtain the endpoint values of parameters for each round, as well as gas and oil production and pressure data, including: Measure and weigh the core to obtain the diameter, length, volume and weight of the core; placing the core in a core holder and applying confining pressure and back pressure to extract air from the core to obtain a vacuum core; Performing water flooding on the vacuum core to obtain a water-saturated core, and obtaining a water-tested effective permeability based on the pressure data before and after the core holder; After removing the water-saturated core, weigh it to obtain the core porosity; Performing oil flooding on the water-saturated core to obtain an oil-saturated core, and obtaining the oil-measured effective permeability based on the pressure difference between the front and rear ends of the core holder; After removing the saturated oil, the core is weighed to obtain the irreducible water saturation and the saturated oil saturation; Performing gas flooding on the oil-saturated core to obtain a gas-flooded oil core, and determining the effective permeability when the gas flooding reaches the residual oil saturation based on the gas and oil production and the pressure difference between the front and rear ends of the core holder; Taking out the gas-driven oil core and weighing it to obtain the liquid saturation; Performing oil-driven gas displacement on the gas-driven oil core to obtain an oil-driven gas core, and obtaining the effective permeability when the oil is driven to the residual gas saturation based on the gas and oil production and the pressure difference between the front and rear ends of the core holder; Taking out the oil-displacement gas core and weighing it to obtain the liquid saturation; Repeat the steps of gas-oil drive-weighing-oil-gas drive-weighing to complete the 2nd to nth rounds of gas-oil drive, and obtain the endpoint values of each parameter in each round.

[0014] In one embodiment, the calculation model is expressed as: (1) (2) in, is the relative permeability of oil when oil, gas and water are three phases; yes = Relative permeability of oil under is the liquid saturation; is the bound gas saturation; It is the oil saturation when oil, gas and water are three phases; is the irreducible water saturation; is the morphological index; is the gas phase relative permeability; yes = relative permeability of downgas; is the gas saturation; is the critical gas saturation; is the irreducible crude oil saturation under the three-phase conditions of oil, gas and water; is the morphological index.

[0015] In a third aspect, an embodiment of the present application provides a computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the phase permeability curve determination method described in the second aspect of the present invention when executing the computer program.

[0016] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the phase permeability curve determination method described in the second aspect of the present invention.

[0017] Compared with the related art, the phase permeability curve measurement device and method for multiple rounds of two-way mutual drive provided in the embodiment of the present application can simulate multiple rounds of gas-oil mutual drive under high temperature and high pressure conditions to accurately measure the endpoint values of the phase permeability curve of multiple rounds of gas-oil mutual drive, and derive the gas-oil mutual drive parameters and the phase permeability curve of each round of gas-oil mutual drive based on the measured endpoint values of the phase permeability curve of multiple rounds of gas-oil mutual drive. On the one hand, it can overcome the problem of pressure control in the conventional pressure difference phase permeability curve measurement method; on the other hand, it can overcome the problem of high requirements for gas and oil production data of traditional phase permeability interpretation methods; on the other hand, it greatly improves the operation of multiple rounds of gas-oil mutual drive phase permeability curve measurement and the success rate of phase permeability curve processing under high temperature and high pressure conditions, and obtains more accurate and reliable phase permeability data.

[0018] The details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 Schematic diagram of the overall structure of a phase permeability curve measuring device suitable for multiple rounds of two-phase flooding provided in an embodiment of the present application; Figure 2 This is a flow chart of a method for determining a phase permeability curve applicable to multiple rounds of two-phase flooding provided in an embodiment of the present application; Figure 3 This is a flow chart of the implementation process of a phase permeability curve determination device suitable for multiple rounds of two-phase flooding provided in an embodiment of the present application; Figure 4 This is a schematic diagram of the phase permeability endpoint values after four rounds of gas-oil mutual flooding provided in the embodiment of the present application; Figure 5 Schematic diagram of the first round of gas drive oil and gas production fitting results provided in the examples of this application; Figure 6 This is a schematic diagram of the fitting results of the first round of gas drive oil production provided in the examples of this application; Figure 7 This is a schematic diagram of the gas production fitting results of the first round of oil drive provided in the examples of this application; Figure 8 This is a schematic diagram of the fitting results of the first round of oil drive gas oil production provided in the examples of this application; Figure 9 Schematic diagram of the parameters of the gas-oil interflooding phase permeability model for each round provided in the embodiments of the present application; Figure 10 Schematic diagram of the permeability curves of each round of gas-oil interdrive provided in the examples of this application.

[0020] In the figure, 1. first constant-pressure constant-speed pump; 2. second constant-pressure constant-speed pump; 3. first displaceable material container; 4. second displaceable material container; 5. third displaceable material container; 6. first hand pump; 7. host computer; 8. humidifying container; 9. first six-way valve; 10. first pressure sensor; 11. temperature box; 12. first data box; 13. core holder; 14. second data box; 15. differential pressure gauge; 16. second pressure sensor; 17. second hand pump; 18. third pressure sensor; 19. gas container; 20. fourth pressure sensor; 21. back pressure valve; 22. collecting bottle; 23. second six-way valve; 24. first pressure-resistant container; 25. second pressure-resistant container; 26. first electronic scale; 27. second electronic scale; 28. third pressure-resistant container; 29. fourth pressure-resistant container; 30. first flowmeter; 31. second flowmeter. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is described and illustrated below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts are within the scope of protection of this application.

[0022] Obviously, the drawings described below are merely examples or embodiments of the present application. Those skilled in the art can, without inventive effort, apply the present application to other similar scenarios based on these drawings. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, changes in design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in this application.

[0023] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments unless there is a conflict.

[0024] Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by persons of ordinary skill in the art to which this application belongs. The terms "a," "an," "an," "the," and similar expressions used herein do not denote quantitative limitations and may refer to either the singular or the plural. The terms "comprise," "include," "have," and any variations thereof, used herein, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or modules (units) is not limited to the listed steps or units but may also include steps or units not listed, or may include other steps or units inherent to the process, method, product, or apparatus. The terms "connected," "connected," "coupled," and similar expressions used herein are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. As used herein, "plurality" means two or more. "And / or" describes an association between associated objects, indicating that three possible relationships exist. For example, "A and / or B" may mean: A exists alone; A and B exist simultaneously; or B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0025] like Figure 1 As shown, this embodiment provides a phase permeability curve measurement device suitable for multiple rounds of two-phase drive, including a measurement system, a core holder 13, an injection system, a temperature box 11, a pressure control system, a data acquisition system, a metering system and a calculation module.

[0026] The measuring system is used to obtain the diameter, length, volume and weight of the core.

[0027] For example, a soft ruler can be used to measure the diameter and length of the core, and the volume can be calculated, and an electronic scale can be used to weigh the core.

[0028] The core holder 13 is used to simulate the gasoline alternating front. The front inlet of the core holder 13 is connected to the outlet of the first six-way valve 9, and a valve is provided on the passage.

[0029] The injection system includes a constant pressure and constant speed pump and a displacement container connected to the constant pressure and constant speed pump, which is used to simulate the displacement injection process. The displacement container is connected to the three inlets of the first six-way valve 9, and valves are set on the three passages.

[0030] Specifically, the constant pressure and constant speed pumps include a first constant pressure and constant speed pump 1 and a second constant pressure and constant speed pump 2. Both constant pressure and constant speed pumps are connected to the displacement material container. The two constant pressure and constant speed pumps can serve as backup equipment for each other. Each constant pressure and constant speed pump can independently inject the displacement material in the displacement material container into the core holder 13.

[0031] Specifically, the displacement container includes: a first displacement container 3 for holding formation crude oil; a second displacement container 4 for holding formation water; a third displacement container 5 for holding high-purity methane; and a humidification container 8 for humidifying gas. The first displacement container 3 connects the constant pressure and constant speed pump to the first inlet of the first six-way valve 9, and the second displacement container 4 connects the constant pressure and constant speed pump to the second inlet of the first six-way valve 9. The third displacement container 5 connects to the constant pressure and constant speed pump. The third displacement container 5 connects to the third inlet of the first six-way valve 9 via the humidification container 8 for humidifying gas. A valve is provided on each section of the pipeline connecting the displacement container to the constant pressure and constant speed pump and the first six-way valve 9.

[0032] The temperature box 11 is used to control the temperature of the core holder 13 and the displacement container placed therein within a set temperature range. Specifically, the temperature range can be set according to actual needs, and the maximum operating temperature of the temperature box is 150°C.

[0033] The pressure control system is in communication with the core holder 13 and is used to control the pressure of the core holder 13 and the injection system within a set pressure range.

[0034] The pressure control system includes: a first hand pump 6, connected to the confining pressure inlet of the core holder 13; a gas container 19 for containing high-purity nitrogen; a second hand pump 18, connected to the gas container 19; a back pressure valve 21, connecting the rear end outlet of the core holder 13 and the gas container 19, and the back pressure valve 21 is connected to the metering system through a second six-way valve 23.

[0035] Specifically, the outlet of the back pressure valve 21 is communicated with the inlet of the second six-way valve 23 .

[0036] Specifically, a first hand pump 6 is used to pump distilled water into the confining pressure inlet of the core holder 13 to control the confining pressure of the core holder 13. A second hand pump 18 is used to pump distilled water into a gas container 19 to push the piston of the gas container 19, and further pump high-purity nitrogen in the gas container 19 into the back pressure valve 21 to control the back pressure of the core holder 13.

[0037] Valves are provided on the passage connecting the first hand pump 6 with the confining pressure inlet of the core holder 13 , the passage connecting the back pressure valve 21 with the rear end outlet of the core holder 13 , and the passage connecting the back pressure valve 21 with the gas container 19 .

[0038] The data acquisition system is used to detect and collect pressure changes at the front and rear ends of the core holder during each displacement. The data acquisition system includes a pressure sensor, a first data box 13 connected to the pressure sensor, a differential pressure gauge 16 connected to both ends of the core holder 13, and a second data box 14 connected to the differential pressure gauge 16. Both data boxes are connected to the computing module. The first data box 13 is used to collect pressure data detected by the pressure sensor, and the second data box 14 is used to collect differential pressure data detected by the differential pressure gauge 116.

[0039] The pressure sensor includes: a first pressure sensor 10, which is provided at the front end inlet of the core holder 13 and is used to detect the pressure at the front end of the core holder 13; a second pressure sensor 16, which is provided at the confining pressure inlet of the core holder 13 and is used to detect the confining pressure of the core holder 13; a third pressure sensor 18, which is provided at the rear end outlet of the core holder 13 and is used to detect the pressure at the rear end of the core holder 13; and a fourth pressure sensor 20, which is provided at the outlet of the back pressure valve 21 and is used to detect the back pressure of the core holder 13.

[0040] The metering system is connected to the rear end outlet of the core holder and is used to measure the mass and volume of the output. The metering system includes: The collecting bottle 22 is connected to the first outlet of the second six-way valve 23 and is used to store the produced waste liquid.

[0041] The first pressure-resistant container assembly includes a first pressure-resistant container 24 for holding produced crude oil and a third pressure-resistant container 28 for holding a desiccant; the first pressure-resistant container 24 is connected to the second outlet of the second six-way valve 23, and the air outlet of the first pressure-resistant container 24 is connected to the air inlet of the third pressure-resistant container 28; a first exhaust pipe communicating with the gas outlet of the third pressure-resistant container 28 and the external atmosphere; The second pressure container assembly includes a second pressure container 25 for holding produced crude oil and a fourth pressure container 29 for holding a desiccant. The second pressure container 25 is connected to the third outlet of the second six-way valve 23, and the air outlet of the second pressure container 25 is connected to the air inlet of the fourth pressure container 29. The capacity of the second pressure container 25 is different from that of the first pressure container 24. a second exhaust pipe connecting the gas outlet of the fourth pressure-resistant container 29 with the external atmosphere; The measuring assembly includes a first electronic scale 26 for placing the first pressure-resistant container assembly and a second electronic scale 27 for placing the second pressure-resistant container assembly; The flowmeter includes a first flowmeter 30 provided on the first exhaust pipe and a second flowmeter 31 provided on the second exhaust pipe. The first flowmeter 30 and the second flowmeter 31 are used to measure the volume of the produced high-purity methane.

[0042] Specifically, the capacity of the first pressure-resistant container 24 is 30 ml, and the capacity of the second pressure-resistant container 25 is 1000 ml. The third pressure-resistant container 28 and the fourth pressure-resistant container 29 are both filled with desiccant to fully dry the gas and obtain accurate oil and gas production.

[0043] The calculation module is used to calculate the endpoint value of the phase permeability curve according to the core parameters, the pressure change at the front and rear ends of the core holder during each displacement, and the mass and volume of the output during each displacement.

[0044] Specifically, in some embodiments, the phase permeability curve measuring device suitable for multiple rounds of two-phase drive further includes a host computer 7, and a storage module is provided in the host computer 7, and the storage module is used to store the core parameters obtained by the measurement system and the pressure changes at the front and rear ends of the core clamp during each drive, and the mass and volume of the output during each drive; the calculation module is provided in the host computer 7, and the calculation module is connected to the storage module, and is used to obtain the core parameters, the pressure changes at the front and rear ends of the core clamp during each drive, and the mass and volume of the output during each drive from the storage module, and calculate the endpoint values of the phase permeability curve.

[0045] The phase permeability curve measuring device suitable for multiple rounds of two-phase drive further includes a vacuum pump, which is connected in series with the core holder.

[0046] The above-mentioned phase permeability curve measurement device suitable for multiple rounds of two-way mutual drive can simulate multiple rounds of gas-oil mutual drive under high temperature and high pressure conditions to accurately measure the phase permeability curves of multiple rounds of gas-oil mutual drive; it can overcome the pressure control problems of the conventional pressure difference phase permeability curve measurement method; it can overcome the problem that the traditional phase permeability interpretation method has high requirements for gas and oil production data; it greatly improves the operation of multiple rounds of gas-oil mutual drive phase permeability curve measurement under high temperature and high pressure conditions and the success rate of phase permeability curve processing, and obtains more accurate and reliable phase permeability data.

[0047] This embodiment also provides a method for determining a phase permeability curve. Figure 2 As shown, the specific steps include the following steps.

[0048] S101, performing multiple rounds of gas-oil mutual flooding using a phase permeability curve measuring device suitable for multiple rounds of two-way mutual flooding, and obtaining endpoint values of parameters for each round, as well as gas and oil production and pressure data; S102, correcting the gas and oil output of each round to obtain an ideal gas and oil output that conforms to the law; S103, substituting the ideal gas and oil production into the gas-drive oil core conceptual model and the oil-drive gas core conceptual model, performing automatic history fitting, and obtaining an optimal morphological index; A feasible method is to use reservoir numerical simulation software (such as CMG, MDS, etc.) to establish a gas-driven oil core conceptual model and an oil-driven gas core conceptual model consistent with the experimental conditions, and use the automatic history fitting method to fit the gas and oil production. During the fitting, the phase permeability endpoint value is kept fixed, and the main adjustment is the morphological index. 、 In the fitting results, the morphological index corresponding to the fitted gas and oil production curve that is closest to the measured production curve is 、 Optimal Shape Index 、 .

[0049] For example, after the first round of gas-oil mutual drive, the gas-oil production fitting results are as follows: Figure 5-Figure 8 shown.

[0050] S104, substituting the optimal morphological index into a calculation model to obtain gas-oil mutual drive parameters and permeability curves of each round of gas-oil mutual drive.

[0051] Specifically, a phase permeability curve is fitted based on the endpoint values and optimal morphological index of each round of gas-oil mutual drive. For gas-to-oil drive, the endpoint values are the oil permeability and liquid saturation before gas drive, and the gas permeability and liquid saturation after gas drive stabilization; for oil-to-gas drive, the endpoint values are the gas permeability and liquid saturation before oil drive, and the oil permeability and liquid saturation after oil drive stabilization. The calculation model is as follows: (1) (2) in, is the relative permeability of oil when oil, gas and water are three phases; yes = Relative permeability of oil under is the liquid saturation; is the bound gas saturation; It is the oil saturation when oil, gas and water are three phases; is the irreducible water saturation; is the morphological index; is the gas phase relative permeability; yes = relative permeability of downgas; is the gas saturation; is the critical gas saturation; is the irreducible crude oil saturation under the three-phase conditions of oil, gas and water; is the morphological index.

[0052] For example, the best morphological index obtained by fitting 、 Substitute into the calculation model to obtain the final parameters of the gas-oil mutual drive phase permeability model for each round as follows: Figure 9 As shown: Among them, round 1.1 represents the first round of gas-to-oil drive, round 1.2 represents the first round of oil-to-gas drive, and so on. is the liquid saturation; is the gas phase relative permeability; is the maximum liquid saturation; is the relative permeability of oil when oil, gas and water are three phases; is the gas saturation; is the maximum gas saturation; is the movable gas saturation; is the irreducible water saturation; is the oil saturation.

[0053] The final permeability curves of each round of gas-oil mutual drive are obtained, as shown in Figure 10 shown.

[0054] It should be noted that when implementing the above method, it is necessary to first check the air tightness of each displacement container, gas container 8, pressure-resistant container, flow meter and core clamp 13 of the device described in the embodiment of the present application, as well as the air tightness of the entire device connected to each instrument through accessories such as pipeline valves.

[0055] Based on the above embodiment, the present embodiment explains the above embodiment S101 in detail. Figure 3 As shown, the specific steps include: S201, measuring and weighing the core to obtain the diameter, length, volume and weight of the core.

[0056] Specifically, the diameter d and length l of the core were measured, the core volume V was calculated, and the core was weighed to obtain the original core weight m1 in preparation for subsequent experiments.

[0057] Preferably, a core with a length greater than 10 cm is selected to reduce the error of the gas and oil production measured by the gas-oil interdrive permeability model.

[0058] S202, placing the core in a core holder and applying confining pressure and back pressure to extract air from the core to obtain a vacuum core; Specifically, the second hand pump 18 is used to control the back pressure valve 21 so that the back pressure valve 21 generates back pressure and reaches the experimental set value.

[0059] The first hand pump 6 is used to control the confining pressure of the core holder 13. Once the set confining pressure is reached, the incubator 11 begins heating the core to the set temperature. At this point, the vacuum pump is connected in series with the core holder 13, and other passages are closed. The vacuum pump is then turned on to extract the air from the core, producing a vacuum core.

[0060] S203, performing water flooding on the vacuum core to obtain a water-saturated core, and obtaining the effective permeability of the water phase based on the pressure data before and after the core holder; Specifically, the first constant pressure and constant speed pump 1 is turned on to pump out distilled water at a low flow rate, and the piston of the second displacement container 4 is pushed to inject formation water into the core holder 13 to obtain a water-saturated core.

[0061] At the same time, record the output flow rate Q and pressure difference during water drive. The value of the output flow rate Q can be calculated based on the readings of the electronic scale and the flow meter in the metering system. The pressure difference is the difference between the readings of the first pressure sensor 10 at the front end of the core holder 13 and the third pressure sensor 18 at the rear end. Since the metering accuracy of the first pressure sensor 10 and the second pressure sensor 19 is too small, a differential pressure gauge 15 with greater metering accuracy is connected in parallel with the core holder 13 to improve the accuracy of the pressure difference data. Compare the value displayed by the differential pressure gauge 15 with the pressure difference value, take a reasonable value as the pressure difference ΔP between the front and rear ends of the core holder 13, and calculate the effective permeability of the water test according to the Darcy formula. The Darcy formula is as follows: (3) The calculation formula of the effective permeability is: (4) Wherein, Q is the output flow rate; K is the effective permeability; A is the cross-sectional area of the core; ΔP is the pressure difference between the front and rear ends of the core holder 13; is the formation water viscosity; l is the core length.

[0062] S204, taking out the water-saturated core and weighing it to obtain the core porosity; Specifically, after the water flooding is completed, the incubator 11 stops heating and the front pressure, rear pressure, and confining pressure of the core holder 13 are released in sequence. After the incubator 11 cools, the core is removed and weighed to obtain the water-saturated core weight m2. The core porosity p is calculated according to the core porosity calculation formula: (5) Where p is the core porosity; m1 is the original core weight; m2 is the core weight after saturation with water; V is the core volume; and ρw is the formation water density.

[0063] S205, performing oil flooding on the water-saturated core to obtain an oil-saturated core, and obtaining the oil-measured effective permeability based on the pressure difference between the front and rear ends of the core holder 13; Specifically, the incubator 11 is turned on for heating. After reaching the set temperature, the water-saturated core is placed back into the core holder 13. The hand pump 6 is used to replenish the confining pressure. The first constant-pressure constant-speed pump 1 is first turned on to pump out distilled water at a low flow rate. The piston of the first displacement container 3 is pushed to inject the formation crude oil into the core holder 13 to obtain the oil-saturated core. At the same time, the output flow rate and pressure difference during oil displacement are recorded. Similarly, the value displayed by the differential pressure gauge 15 is compared with the pressure difference value. A reasonable pressure difference value is taken as the pressure difference ΔP between the front and rear ends of the core holder 13. Referring to the effective permeability calculation formula (4), the oil-tested effective permeability is calculated.

[0064] S206, taking out the oil-saturated core and weighing it to obtain irreducible water saturation and saturated oil saturation; Specifically, after the oil flooding is completed, the heating box 11 stops heating, and the front pressure, rear pressure and confining pressure of the core holder 13 are released in sequence. After the incubator 11 cools down, the core is taken out and weighed to obtain the mass m3 of the core saturated with oil, and the bound water saturation is calculated. and oil saturation after saturation The irreducible water saturation The calculation formula is: (6) in, is the bound water saturation; is the core mass after saturation with oil; ρw is the formation water density; is the density of formation crude oil; p is the core porosity; V is the core volume.

[0065] The oil saturation after saturation The calculation formula is: (7) S207, performing gas flooding on the oil-saturated core to obtain a gas flooded oil core, and obtaining the gas phase effective permeability based on the gas and oil production flow rate and the pressure difference between the front and rear ends of the core holder 13; Specifically, the incubator 11 is turned on for heating. After reaching the set temperature, the oil-saturated core is placed back in the core holder 13. The confining pressure is replenished with the hand pump 6. The first constant-pressure constant-speed pump 1 is turned on first to perform a round of oil drive. When the output flow rate and pressure data are stable, the pressure data is recorded. Then, the first constant-pressure constant-speed pump 1 is turned off, and the second constant-pressure constant-speed pump 2 is turned on. The high-purity methane in the third displacement container 5 is pumped into the core holder 13 at a constant flow rate after being humidified by the humidification container 8, and the gas drive for oil is started.

[0066] When the production end starts to produce oil, the readings of the first electronic scale 26 and the first wet gas flow meter 31 are recorded. The reading of the first electronic scale 26 is the mass of the produced formation crude oil, and the reading of the first flow meter 30 is the volume of the produced high-purity methane, and they are recorded separately at regular intervals thereafter.

[0067] It should be noted that, because the first pressure-resistant container 24 at the output end is connected in series with the third pressure-resistant container 28 filled with desiccant, most of the produced formation crude oil is retained in the first pressure-resistant container 24 and the third pressure-resistant container 28 filled with desiccant. Therefore, the mass of the produced formation crude oil can be measured by the electronic scale 27, and the volume of the produced high-purity methane measured by the flow meter is also relatively accurate.

[0068] According to the quality of the produced formation crude oil, the volume of high-purity methane produced and the density of the formation crude oil The output flow rates of formation crude oil and high-purity methane in different time periods are calculated, and the pressure difference between the front and rear ends of the core holder 13 is recorded at each time period. The gas phase effective permeability is obtained by referring to the effective permeability calculation formula (4).

[0069] Preferably, when performing n rounds of gas-oil mutual flooding and mutual permeation, in order to reduce the experimental error of gas-oil production, it should be ensured that the time of each round of flooding is long enough.

[0070] S208, taking out the gas-driven oil core and weighing it to obtain the liquid saturation; Specifically, after the high-purity methane injection volume reaches the set value, the second constant pressure and constant speed pump 2 is turned off, the incubator 11 stops heating, and the front pressure, rear pressure and confining pressure of the core holder 13 are released in sequence. After the incubator 11 cools down, the core is taken out and weighed to obtain the gas-flooded core mass. The oil saturation after gas-flooding is calculated based on the gas-flooded core mass. Liquid saturation after gas flooding .

[0071] For example, taking the first round of gas flooding as an example, the core quality of the first round of gas flooding is obtained. Calculate the oil saturation after the first round of gas flooding based on the core quality of the first round of gas flooding. and the liquid saturation after the first round of gas flooding .

[0072] Oil saturation after the first round of gas flooding The calculation formula is as follows: (8) in, is the oil saturation after the first round of gas flooding; is the oil saturation; It is the core quality after the first round of gas flooding; is the core mass after saturation with oil; is the density of formation crude oil; p is the core porosity; V is the core volume.

[0073] According to the oil saturation after the first round of gas flooding Calculate formula (9) to obtain the liquid saturation after the first round of gas flooding , the calculation formula is as follows: (9) in, is the liquid saturation after the first round of gas flooding; is the bound water saturation; It is the oil saturation after the first round of gas flooding.

[0074] The calculation methods for liquid saturation after gas flooding of other rounds can refer to the liquid saturation method after gas flooding of the first round. In fact, the calculation steps and methods are similar and will not be repeated here.

[0075] S209, performing oil-displacing gas on the gas-displacing oil core to obtain an oil-displacing gas core, and obtaining the effective permeability of the oil phase based on the gas and oil production and the pressure difference between the front and rear ends of the core holder 13; Specifically, the incubator 11 is turned on for heating. After reaching the set temperature, the oil-displacement gas core is reversed and placed in the core holder 13. The confining pressure is supplemented by the first hand pump 6. The second constant-pressure and constant-speed pump 2 is turned on first, and then a round of gas drive is performed. When the output flow rate and pressure data are stable, the pressure data is recorded. After that, the second constant-pressure and constant-speed pump 2 is turned off, and the first constant-pressure and constant-speed pump 1 is turned on. The formation crude oil in the first displacement container 3 is injected into the core holder 13 at a certain flow rate to perform oil-displacement gas drive.

[0076] When the production end starts to produce high-purity methane, the readings of the second electronic scale 27 and the second flow meter 31 are recorded. The reading of the first electronic scale 28 is the mass of the produced formation crude oil, and the reading of the second flow meter 31 is the volume of the produced high-purity methane. The readings are recorded at regular intervals thereafter. Based on the mass of the produced formation crude oil, the volume of the produced high-purity methane and the density of the formation crude oil, the The output flow rates of formation crude oil and high-purity methane in different time periods are calculated, and the pressure difference between the front and rear ends of the core holder 13 is recorded at each time period. Referring to the effective permeability calculation formula (4), the oil phase effective permeability is obtained.

[0077] S210, taking out the oil-displacement gas core and weighing it to obtain the liquid saturation.

[0078] Specifically, after the amount of crude oil injected into the formation reaches the experimental design level, the constant pressure and constant speed pump 1 is turned off, the heating box 11 stops heating, and the pressure and the confining pressure at the front and rear ends of the core holder 13 are released in sequence. After the incubator 11 cools down, the core is taken out and weighed to obtain the mass of the oil-driven gas core. The oil saturation after oil-driven gas is calculated based on the mass of the oil-driven gas core. .

[0079] For example, taking the first round of oil-gas displacement as an example, the core quality after the first round of oil-gas displacement is obtained. Calculate the oil saturation after the first round of oil flooding based on the core mass after the first round of oil flooding. .

[0080] Oil saturation after the first round of oil-gas displacement The calculation formula is as follows: (10) in, is the oil saturation after the first round of oil flooding; is the core quality after the first round of oil-gas displacement; is the core mass after saturation with oil; is the density of formation crude oil; p is the core porosity; V is the core volume.

[0081] According to the oil saturation after the first round of oil flooding Calculate formula (10) to obtain the liquid saturation after the first round of oil displacement: , the calculation formula is as follows: (11) in, is the liquid saturation after the first round of gas flooding; is the bound water saturation; It is the oil saturation after the first round of gas flooding.

[0082] The calculation method of liquid saturation after oil-gas displacement in other rounds can refer to the liquid saturation method after gas-oil displacement in the first round. In fact, the calculation steps and methods are similar and will not be repeated here.

[0083] S211, repeating the steps of gas-oil displacement-weighing-oil-gas displacement-weighing to complete the second to nth rounds of gas-oil displacement, and obtaining the endpoint values of each parameter in each round.

[0084] For example, when a constant flow rate is used for gas-oil mutual drive, the injection rate must meet the following requirements: (12) That is, the critical flow must meet the following requirements: (13) Wherein, L is the core length; is the viscosity of the formation crude oil at the measurement temperature; Seepage velocity; Q is the critical flow rate; A is the core cross-sectional area; is the porosity.

[0085] Taking the core with a permeability of 14.24 mD as an example, four rounds of gas-oil flooding were carried out, and the phase permeability endpoint values after four rounds of gas-oil flooding were obtained as follows: Figure 4 shown.

[0086] Among them, Kro-1.1 is the oil permeability before the first round of gas drive and oil-gas drive; Krg-1.1 is the relative permeability of oil and gas phase in the first round of gas drive; Kro-1.2 is the relative permeability of gas-oil phase in the first round of oil drive; Krg-1.2 is the gas phase permeability before the first round of oil drive and gas-oil drive; and so on.

[0087] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0088] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A device for measuring phase permeability curves suitable for multiple rounds of two-phase driving, characterized in that: include: A measurement system for obtaining core parameters, including diameter, length, volume, and weight of the core; core holder to simulate the gasoline alternating front; An injection system for simulating a displacement material injection process; the injection system comprises a constant pressure and constant speed pump and a displacement material container connected to the constant pressure and constant speed pump, wherein the displacement material container is connected to a front inlet of the core holder; A temperature box, used to control the temperature of the core holder and the displacement material container placed therein within a set temperature range; a pressure control system, in communication with the core holder, for controlling the pressure of the core holder and the injection system within a set pressure range; A data acquisition system for detecting and collecting pressure changes at the front and rear ends of the core holder during each displacement; a metering system, connected to the rear end outlet of the core holder, for measuring the mass and volume of the output; The calculation module is used to calculate the endpoint value of the phase permeability curve according to the core parameters, the pressure change at the front and rear ends of the core holder during each displacement, and the mass and volume of the output during each displacement.

2. The phase permeability curve measuring device suitable for multiple rounds of two-phase drive according to claim 1 is characterized in that: The displacement material container is communicated with the front end inlet of the core holder through a first six-way valve, and a valve is provided on the passage connecting the front end inlet of the core holder and the first six-way valve.

3. The phase permeability curve measuring device suitable for multiple rounds of two-phase drive according to claim 2, characterized in that: The displacement container comprises: a first displacement material container, connected to the constant pressure and constant speed pump and the first inlet of the first six-way valve, for containing formation crude oil; a second displacement material container, connected to the constant pressure and constant speed pump and the second inlet of the first six-way valve, for containing formation water; a third displacement container, connected to the constant pressure constant speed pump, for containing high-purity methane; the third displacement container is connected to the third inlet of the first six-way valve through a humidifying container for humidifying gas; Each section of the pipeline connecting the displacement material container with the constant pressure and constant speed pump and the first six-way valve is provided with a valve.

4. The device for measuring phase permeability curves suitable for multiple rounds of two-phase flooding according to claim 1, characterized in that: The pressure control system comprises: a first hand pump connected to the confining pressure inlet of the core holder; Gas container for holding high-purity nitrogen; a second hand pump connected to the gas container; a back pressure valve, connecting the rear end outlet of the core holder and the gas container, the back pressure valve being connected to the metering system via a second six-way valve; Valves are provided on the passage connecting the first hand pump and the confining pressure inlet of the core holder, the passage connecting the back pressure valve and the rear end outlet of the core holder, and the passage connecting the back pressure valve and the gas container.

5. The device for measuring phase permeability curves suitable for multiple rounds of two-phase flooding according to claim 4, characterized in that: The data acquisition system includes a pressure sensor, a first data box connected to the pressure sensor, a differential pressure gauge connected to both ends of the core holder, and a second data box connected to the differential pressure gauge. Both data boxes are connected to a computing module. The first data box is used to collect pressure data detected by the pressure sensor, and the second data box is used to collect differential pressure data detected by the differential pressure gauge. The pressure sensor includes: A first pressure sensor is provided at the front inlet of the core holder and is used to detect the pressure at the front end of the core holder; a second pressure sensor, provided at the confining pressure inlet of the core holder, for detecting the confining pressure of the core holder; a third pressure sensor, provided at the rear end outlet of the core holder, for detecting the rear end pressure of the core holder; The fourth pressure sensor is provided at the outlet of the back pressure valve and is used to detect the back pressure of the core holder.

6. The device for measuring phase permeability curves suitable for multiple rounds of two-phase flooding according to claim 4, characterized in that: The metering system comprises: a collecting bottle, the collecting bottle being connected to the first outlet of the second six-way valve and being used for storing the produced waste liquid; a first pressure-resistant container assembly comprising a first pressure-resistant container for holding produced crude oil and a third pressure-resistant container for holding a desiccant; the first pressure-resistant container being in communication with the second outlet of the second six-way valve, and the air outlet of the first pressure-resistant container being in communication with the air inlet of the third pressure-resistant container; a first exhaust pipe, connecting the gas outlet of the third pressure-resistant container with the external atmosphere; a second pressure-resistant container assembly comprising a second pressure-resistant container for holding produced crude oil and a fourth pressure-resistant container for holding a desiccant; the second pressure-resistant container is in communication with the third outlet of the second six-way valve, and the air outlet of the second pressure-resistant container is in communication with the air inlet of the fourth pressure-resistant container; the capacity of the second pressure-resistant container is different from that of the first pressure-resistant container; a second exhaust pipe, communicating the gas outlet of the fourth pressure-resistant container with the external atmosphere; The measuring assembly includes a first electronic scale for placing the first pressure-resistant container assembly and a second electronic scale for placing the second pressure-resistant container assembly; The flow meter comprises a first flow meter arranged on the first exhaust pipe and a second flow meter arranged on the second exhaust pipe, wherein the first flow meter and the second flow meter are used to measure the volume of the output high-purity methane.

7. The device for measuring phase permeability curves suitable for multiple rounds of two-phase flooding according to claim 1, characterized in that: The phase permeability curve measuring device suitable for multiple rounds of two-phase drive further includes a vacuum pump, which is connected in series with the core holder.

8. A method for determining a phase permeability curve, characterized in that: Using the phase permeability curve measuring device suitable for multiple rounds of two-phase flooding as described in any one of claims 1 to 7, the method includes: Using a phase permeability curve measurement device suitable for multiple rounds of two-way flooding, multiple rounds of gas-oil flooding were carried out to obtain the endpoint values of each round's parameters, as well as gas and oil production and pressure data; Correcting the gas and oil outputs of each round to obtain an ideal gas and oil output; Substituting the ideal gas and oil production into the gas-drive-oil core conceptual model and the oil-drive-gas core conceptual model, performing automatic history fitting, and obtaining the optimal morphological index; The optimal morphological index is substituted into the calculation model to obtain the gas-oil mutual drive parameters and the gas-oil mutual drive phase permeability curves of each round.

9. The method according to claim 8, characterized in that The method of performing multiple rounds of gas-oil mutual flooding using a phase permeability curve measuring device suitable for multiple rounds of two-way mutual flooding to obtain the endpoint values of parameters of each round, as well as gas and oil production and pressure data, includes: Measure and weigh the core to obtain the diameter, length, volume and weight of the core; placing the core in a core holder and applying confining pressure and back pressure to extract air from the core to obtain a vacuum core; Performing water flooding on the vacuum core to obtain a water-saturated core, and obtaining a water-tested effective permeability based on the pressure data before and after the core holder; After taking out the saturated water, the core is weighed to obtain the core porosity; Performing oil flooding on the water-saturated core to obtain an oil-saturated core, and obtaining the oil-measured effective permeability based on the pressure difference between the front and rear ends of the core holder; After removing the saturated oil, the core is weighed to obtain the irreducible water saturation and the saturated oil saturation; Performing gas flooding on the oil-saturated core to obtain a gas-flooded oil core, and determining the effective permeability when the gas flooding reaches the residual oil saturation based on the gas and oil production and the pressure difference between the front and rear ends of the core holder; Taking out the gas-driven oil core and weighing it to obtain the liquid saturation; Performing oil-driven gas displacement on the gas-driven oil core to obtain an oil-driven gas core, and obtaining the effective permeability when the oil is driven to the residual gas saturation based on the gas and oil production and the pressure difference between the front and rear ends of the core holder; Taking out the oil-displacement gas core and weighing it to obtain the liquid saturation; Repeat the steps of gas-oil drive-weighing-oil-gas drive-weighing to complete the 2nd to nth rounds of gas-oil drive, and obtain the endpoint values of each parameter in each round.

10. The method according to claim 8, characterized in that The calculation model is expressed as: (1) (2) in, is the relative permeability of oil when oil, gas and water are three phases; yes = Relative permeability of oil under is the liquid saturation; is the bound gas saturation; It is the oil saturation when oil, gas and water are three phases; is the irreducible water saturation; is the morphological index; is the gas phase relative permeability; yes = relative permeability of downgas; is the gas saturation; is the critical gas saturation; is the irreducible crude oil saturation under the three-phase conditions of oil, gas and water; is the morphological index.

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