CN113834762A - Method and system for measuring gas-water relative permeability curve - Google Patents
Method and system for measuring gas-water relative permeability curve Download PDFInfo
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 186
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- 238000000034 method Methods 0.000 title claims abstract description 72
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Abstract
The invention relates to a method and a system for measuring a gas-water relative permeability curve, which belong to the technical field of petroleum and natural gas, wherein a rock core to be measured is saturated with formation water; calculating the displacement pressure of the gas drive and the displacement flow of the water drive according to the environment outside the source of the rock core to be detected; performing a gas-flooding water experiment and a water-flooding gas experiment, and calculating the relative permeability of a gas phase and the relative permeability of a water phase in the gas flooding process according to the mass/flow of formation water driven out by gas flooding and the gas flow; calculating the relative permeability of a gas phase and the relative permeability of a water phase in the water flooding process according to the displacement flow of the water flooding and the gas flow driven out by the water flooding; the method comprises the steps of constructing a gas phase relative permeability curve and a water phase relative permeability curve to solve the problems of low injection and production engineering efficiency and high difficulty of a gas reservoir type gas storage caused by the fact that the existing gas-water relative permeability curve cannot truly describe the actual conditions of each stage of the gas storage.
Description
Technical Field
The invention relates to the technical field of petroleum and natural gas, in particular to a method and a system for measuring a gas-water relative permeability curve.
Background
The gas-water relative permeability curve is an important tool for describing the gas-water two-phase flow rule in the porous medium, and is an important basis for the safe construction, the efficient operation and the smooth development of subsequent related special researches of a gas reservoir type gas storage.
The gas storage type gas storage has three functions of seasonal peak regulation, accident emergency and national energy strategic storage, and the function determines the special working condition of the gas storage for multi-period injection and production. Under the multi-cycle injection-production working condition, the gas-water two-phase seepage rule changes along with the progress of the injection-production cycle and is not invariable. Therefore, the conventional gas-water relative permeability curve can only represent the condition of a gas injection or gas production stage in one injection-production period, and the curve cannot accurately describe the change condition of gas-water two-phase seepage after multi-period injection-production in the actual working process, so that the curve deviates from the actual condition when the construction and application of a gas storage pool are researched.
Moreover, in the currently generally adopted gas-water phase permeability test method, the gas-water phase permeability is usually tested by adopting a gas-water flooding mode, in the operation process of an actual gas storage, the gas production stage is mainly the water gas flooding condition, the gas-water relative permeability curve is greatly influenced by the fluid saturation sequence, the relative permeability curve tested by adopting the gas-water flooding mode cannot reflect the actual condition in the underground gas storage, and the guiding significance for the development of the actual water gas-flooding gas storage is not great. Therefore, the existing gas-water relative permeability curve cannot truly describe the actual conditions of each stage of the gas storage, so that the related research and application carried out by using the gas-water relative permeability curve are not in accordance with the engineering practice, thereby increasing the difficulty of implementing work such as multi-cycle injection and mining and the like and reducing the engineering efficiency.
Disclosure of Invention
The invention aims to provide a method and a system for measuring a gas-water relative permeability curve, which are used for solving the problems of low injection and production engineering efficiency and high difficulty of a gas reservoir type gas reservoir caused by the fact that the existing gas-water relative permeability curve cannot truly describe the actual conditions of each stage of the gas reservoir.
In order to achieve the purpose, the technical scheme of the invention is as follows: the invention provides a method for measuring a gas-water relative permeability curve, which comprises the following steps:
1) saturating formation water with a core to be tested;
2) calculating the displacement pressure of the gas drive and the displacement flow of the water drive according to the environment outside the source of the rock core to be detected;
3) performing a gas flooding experiment:
injecting gas into the core to be tested according to the displacement pressure of the gas drive, and measuring the mass/flow of the expelled formation water and the gas flow in real time; further calculating the relative permeability of the gas phase and the relative permeability of the water phase in the gas flooding process;
4) performing a water flooding experiment:
according to the displacement flow of the water drive, injecting formation water into the core to be tested, measuring the gas flow driven out by the water drive in real time, and calculating the relative permeability of the gas phase and the relative permeability of the water phase in the water drive process according to the displacement flow and the gas flow driven out by the water drive;
5) a gas phase relative permeability curve and a water phase relative permeability curve were constructed.
The method comprises the steps of fully simulating the actual operating environment of the gas storage injection and production cycle, simulating gas injection work of the gas storage through a gas flooding experiment in each cycle, simulating gas production work of the gas storage through water flooding, respectively measuring a corresponding gas phase relative permeability curve and a corresponding water phase relative permeability curve in displacement experiments of two stages, and highly approaching the actual operating environment in the gas storage in the curve measuring process. The obtained gas-water relative permeability curve can truly describe the actual situation of each stage of the gas storage, effectively improves the injection and production engineering efficiency of the gas storage type gas storage, and creates favorable conditions for the multi-period injection and production work of the gas storage.
Further, in order to better meet engineering practice, in the gas flooding experiment, gas is injected from one side of the core to be detected, and then, in the water flooding experiment, formation water is injected from the other side of the core to be detected.
Further, in order to obtain actual relative permeability conditions of different injection-production periods, repeating the steps 3) to 5), and obtaining a gas phase relative permeability curve and a water phase relative permeability curve of multiple periods.
Further, the step 2) also comprises the steps of calculating confining pressure, and carrying out a gas-water driving experiment and a water-gas driving experiment under the confining pressure; the confining pressure is greater than the displacement pressure.
Further, in order to improve the accuracy of the determination process, the steps 3) and 4) further include the step of vacuumizing the experiment pipeline before the experiment.
Further, in the step 2), the calculation formula of the relative permeability of the gas phase, the relative permeability of the water phase and the irreducible water saturation is as follows:
Swi＝(Gw-Gwi)/Gw
△Pi＝P1i-P2i
Qwi＝Gwi/ρw
Krwi＝(QwiμwL)/(kA△Pi)
Krgi＝(QgiμgL)/(kA△Pi)
Swc1＝(Gw-Gwit)/Gw
in the formula: swiThe water saturation of the rock core at the time t in the gas flooding process is shown; gwiThe average value of the quality of the formation water continuously driven out for n seconds in the gas drive process; gwThe wet weight of the core under normal pressure; p1iFor rock at t moment in gas flooding processHeart inlet end mean pressure; p1iThe pressure of the outlet end of the rock core at the time t in the gas flooding process is shown; delta PiThe pressure difference between two ends of the rock core at the time t in the gas flooding process; qwiThe formation water flow at the time t in the gas flooding process; qgiThe gas flow at the time t in the gas flooding process; k is the absolute permeability of the rock core; krwiAs the water saturation SwiRelative permeability of the aqueous phase; krgiAs the water saturation SwiRelative permeability of the gas phase; swc1Irreducible water saturation; gwitIs the total mass of formation water displaced during the gas flooding process.
Further, in the step 3), the calculation formula of the relative permeability of the gas phase and the relative permeability of the water phase is as follows:
Swj＝Swc1+(nρwQwj)/Gw
△Pj＝P2j-P1j
Krwj＝(QwjμwL)/(kA△Pj)
Krgj＝(QgjμgL)/(kA△Pj)
wherein S iswjThe water saturation, Q, of the rock core in the water flooding processgjIs the average gas flow, Q, in the water flooding processwjDisplacement flow for water flooding, Swc1The irreducible water saturation of the gas flooding water and n is the time.
Further, the step 4) further comprises calculating the residual gas saturation according to the irreducible water saturation and the displacement flow, wherein the calculation formula is as follows:
Sgr1＝1-Swc1-TQwj
in the formula: sgr1The residual gas saturation in the water flooding process; t is the experimental time.
The invention also provides a system for measuring the gas-water relative permeability curve, which comprises:
the core holder is used for holding a core to be measured;
the displacement pump is used for providing displacement power;
the gas drive water pipeline is connected with the displacement pump and the rock core holder and is used for carrying out a gas drive water experiment;
the water drive gas pipeline is connected with the displacement pump and the core holder and is used for performing a water drive gas experiment;
the gas flowmeter is arranged at the downstream of the gas drive water pipeline and the water drive gas pipeline and is used for detecting the gas flow;
and the formation water quality/flow detector is arranged at the downstream of the gas drive water pipeline and the water drive gas pipeline and is used for detecting the formation water quality/flow.
According to the invention, a gas-driving water pipeline and a water-driving gas pipeline are arranged in a gas-water relative permeability curve measuring system, gas injection work of the gas storage is simulated through a gas-driving water experiment in each period, gas production work of the gas storage is simulated through a water-driving gas experiment, corresponding gas-phase relative permeability curves and water-phase relative permeability curves are respectively measured in displacement experiments of two stages, and the height of the curve measuring process is close to the actual working environment in the gas storage. The obtained gas-water relative permeability curve can truly describe the actual situation of each stage of the gas storage, effectively improves the injection and production engineering efficiency of the gas storage type gas storage, and creates favorable conditions for the multi-period injection and production work of the gas storage.
Further, in the gas-driven water pipeline, gas enters from the first end of the core holder and is output from the second end of the core holder; in the water-driven gas pipeline, formation water enters from the second end of the core holder and is output from the first end of the core holder.
Drawings
FIG. 1 is a schematic view of a measuring system used in an embodiment of the method for measuring a gas-water relative permeability curve of the present invention;
FIG. 2 is a flow chart of a method in an embodiment of the method for determining a gas-water relative permeability curve of the present invention;
in the figure, 1-confining pressure pump, 2-back pressure pump b, 3-displacement pump, 4-PC control end, 5-back pressure valve a, 6-valve c, 7-valve d, 8-valve e, 9-hexagonal valve a, 10-three-way valve a, 11-pressure sensor a, 12-valve g, 13-core holder, 14-valve h, 15-pressure sensor b, 16-three-way valve b, 17-hexagonal valve b, 18-back pressure valve b, 19-valve i, 20-back pressure pump a, 21-drying pipe b, 22-balance b, 23-gas flowmeter, 24-valve b, 25-high pressure gas source, 26-valve a, 27-formation water, 28-vacuum meter a, 29-valve f, 30-vacuum gauge b, 31-valve j, 32-drying tube a, 33-balance a, 34-vacuum pump, 35-incubator.
Detailed Description
The following are three embodiments of examples of the method for measuring a gas-water relative permeability curve of the present invention.
Embodiment 1:
the gas-liquid relative permeability curve is an important reference data in dynamic analysis and numerical simulation of gas reservoir development, and the curve is usually obtained by testing a real gas reservoir core in a laboratory through a steady state method or an unsteady state method. Because the basic principle of the steady state method is one-dimensional darcy seepage, the steady state method for testing gas-water phase seepage mainly has three limitations: firstly, the experimental process of testing gas-water phase permeation by adopting a steady-state method requires that a smaller displacement differential pressure is required to be kept under the condition of ensuring that no turbulent flow is generated so as to ensure that the flow rate of gas is smaller, and the influence of the end effect in the experimental process is difficult to eliminate by adopting the smaller displacement differential pressure; secondly, the gas logging permeability of the tested rock core specified in the existing gas-water phase permeability test standard is necessarily greater than 0.5mD, so that the application range of the gas logging permeability is limited; thirdly, the steady state method has long testing period of gas-water phase permeation.
Because of the limitations of the steady-state method, the currently widely adopted gas-water phase permeation test method is an unsteady-state method. However, the existing unsteady method for testing gas-water phase permeability also has certain limitations, for example, when the existing unsteady method is used for measuring a gas-water relative permeability curve, a gas-flooding water mode is usually adopted for testing, and in the actual gas reservoir development process, the processes such as edge water propulsion and the like generally present a water-flooding gas state, and the gas-water relative permeability curve is greatly influenced by a fluid saturation sequence, so that the guiding significance of the gas-water relative permeability curve tested by the gas-flooding water mode on the actual water-flooding gas reservoir development is not great.
In order to be more suitable for the actual operation environment in the gas storage, a more accurate gas-water relative permeability curve is obtained, and therefore effective basis is provided for the effective analysis of the operation dynamics of the gas storage, the operation efficiency adjustment, the injection and production capacity analysis and the like. In the embodiment, the gas-water relative permeability curve is comprehensively determined through a gas-water flooding experiment and a water-gas flooding experiment.
In this embodiment, the measurement system shown in fig. 1 is mainly used, and includes a core holder, the core holder is placed in a thermostat, and the confining pressure end of the core holder is connected to a confining pressure pump. The measuring system mainly comprises a gas drive water pipeline and a water drive gas pipeline so as to realize a gas drive water experiment and a water drive gas experiment.
The end a (left side) of the rock core holder is sequentially connected with a valve g, a pressure sensor a, a valve No. 3 and a valve No. 1 of a three-way valve a, a valve No. 4 and a valve No. 1 of a hexagonal valve a, the valve No. 1 of the hexagonal valve a is connected with two branches in parallel, a first branch is sequentially connected with a valve c, a formation water source and the valve a, a second branch is sequentially connected with a valve d, a back pressure valve a, a high-pressure air source and a valve b, the two branches are connected with a displacement pump after being converged, and the back pressure end of the back pressure valve a is sequentially connected with a valve e and a back pressure pump b; the end b (right side) of the core holder is sequentially connected with a valve h, a pressure sensor b, a valve No. 1 and a valve No. 3 of a three-way valve b, a valve No. 1 and a valve No. 4 of a hexagonal valve b, a back pressure valve b, a drying pipe b and a gas flowmeter b, the drying pipe b is placed on an electronic balance b for weighing, and the back pressure end of the back pressure valve b is sequentially connected with a valve i and a back pressure pump a;
the valve No. 5 of the hexagonal valve a is communicated with the valve No. 2 of the three-way valve b through a pipeline, the valve No. 2 of the three-way valve a is communicated with the valve No. 2 of the hexagonal valve b through a pipeline, a vacuum meter a, a valve f, a valve j and a vacuum meter b are sequentially connected between the valve No. 3 of the hexagonal valve a and the valve No. 3 of the hexagonal valve b, an inlet of a drying pipe a is connected between the vacuum meter a and the vacuum meter b, an outlet of the drying pipe a is connected with a vacuum pump, the drying pipe a is placed on an electronic balance a for weighing, and the valve No. 6 of the hexagonal valve a and the valve No. 6 of the hexagonal valve b are used for emptying;
the confining pressure pump, the back pressure pump a, the back pressure pump b, the displacement pump, the electronic balance a and the electronic balance b are respectively connected with the computer.
In this embodiment, the purpose of the hex valve a, the hex valve b, the three-way valve a and the three-way valve b is mainly to form a core holder communicated with two independent pipelines in the air-flooding water experiment and the water-flooding air experiment. As an improvement to this embodiment, two parallel lines may also be directly used, with one check valve in each line.
In the present embodiment, the measurement method will be described in detail by taking an example of measuring a relative permeability curve in one injection and production cycle. The following describes the measurement method of the present invention in detail, and as shown in FIG. 2, the method mainly includes the following steps:
step S1, experimental preparation:
1) measuring the dry weight G of the core to be measureddLength L, diameter R, cross-sectional area A, porosity
And basic physical parameters such as permeability K;
2) volume VwFormation water weighing mwAnd calculating the configured water density rho of the stratumw，
ρw＝mw/Vw
In the formula: m iswKg is the formation water mass; vwIs the volume of formation water, m3；ρwIs the density of the formation water in kg/m3，
3) Respectively testing and calculating the viscosity mu of the formation water and the experimental gas under the conditions of the design core holder outlet end back pressure and the experimental temperaturewAnd mug；
4) Cleaning and drying a core to be tested and saturating formation water for experiments (the formation water is prepared according to the salinity of the formation water in a core sampling area, and is hereinafter referred to as formation water for short);
5) putting a rock core to be measured into a rock core holder, adding confining pressure, using gas to displace the rock core until no water is discharged, then using a displacement pump to displace the rock core into experimental formation water at a constant flow rate, observing the reading of a pressure sensor at the inlet end of the rock core, and reducing the flow rate set by the displacement pump if the reading of the sensor rises all the time and does not tend to be stable until the reading of the pressure sensor can tend toA stable value, using the flow as displacement flow Q of water displacement gaswj，
6) Drying the core again and saturating formation water for experiment (the formation water is prepared according to the salinity of the formation water in a core sampling area), and weighing the wet weight G of the corew1。
Step S2, simulating the operation environment of the gas storage:
1) keeping all valves closed, loading a core to be tested into a core holder, opening a valve g and a valve h at two ends of the core holder, setting confining pressure according to overburden pressure of a core source gas storage, and starting a confining pressure pump (determined according to overburden pressure of the core source gas storage, but at least 3MPa greater than designed displacement pressure so as to ensure the tightness of an experimental system);
2) opening valves 3 and 4 of the hexagonal valve a, valves 1 and 3 of the three-way valve b, valves 1 and 3 of the hexagonal valve b, valve f and valve j, opening a vacuum pump, closing the valve G and the valve h after pumping for 3-5 seconds, then continuing pumping the formation water in the pipeline into the drying pipe a, then closing the vacuum pump, closing the valves 3 and 4 of the hexagonal valve a, valves 1 and 3 of the three-way valve b, valves 1 and 3 of the hexagonal valve b, valve f and valve j, and recording the mass G of the formation water pumped by the electronic valve aw2Calculating the wet weight G of the core under pressurew；
Gw＝Gw1-Gw2
In the formula: gw1The wet weight of the core under normal pressure is kg; gw2The mass of formation water pressed out of the rock core under confining pressure is kg;
3) opening a valve i and a back pressure valve b, calculating back pressure according to the original formation pressure of the core source gas storage and the designed injection-production differential pressure of the gas storage, and setting and starting a back pressure pump a according to the back pressure;
4) and setting a constant temperature box according to the reservoir temperature of the core source gas storage and starting the constant temperature box to ensure that the experiment temperature is constant and is the reservoir temperature of the core source gas storage.
Step S3, simulating a gas storage gas injection working flow in a gas drive water experiment:
1) opening valves 1, 3 and 4 of a hexagonal valve a, valves 1 and 3 of a three-way valve b, valves 1 and 3 of a hexagonal valve b, a valve f and a valve j, opening a vacuum pump, observing the vacuum meter a and the vacuum meter b, closing the vacuum pump after the displacement system pipeline and the valve are vacuumized, closing the valves 3 of the hexagonal valve a, valves 3 and f and the valve j of the hexagonal valve b, and opening valves b, d, e, a back-pressure valve a and valves 4 of the hexagonal valve b;
2) setting a back pressure pump according to the designed displacement pressure, starting the back pressure pump, opening the displacement pump to enable gas to enter the rock core from one end of the rock core holder at the displacement pressure higher than the pressure of the back pressure pump, driving formation water out of the other end of the rock core holder to a drying pipe b, reading the value of a high-precision electronic balance b in real time, continuously recording the mass of the formation water driven out for n seconds and calculating the average value GwiAnd formation water flow rate Q within n secondswiRecording the data of the high-precision gas flowmeter within n seconds in real time to obtain the average gas flow QgiSimultaneously recording average values P of readings of pressure sensors at the inlet end and the outlet end of the rock core within n seconds1iAnd P2i(in this case, the pressure sensor a is an inlet end pressure sensor, and the pressure sensor b is an outlet end pressure sensor), and the differential pressure deltaP between two ends of the rock core is calculatediCalculating the water saturation S of the rock core according to the mass of the water driven out of the stratumwiCalculating the relative permeability of gas and formation water under the water saturation according to the gas flow, the formation water flow and the core absolute permeability (each expelled formation water quality can calculate a water saturation value, and correspondingly calculate a gas flow and a pressure difference), and at least acquiring more than 7 groups of data to ensure that the relative permeability curve form is relatively smooth;
Swi＝(Gw-Gwi)/Gw
△Pi＝P1i-P2i
Qwi＝Gwi/ρw
Krwi＝(QwiμwL)/(kA△Pi)
Krgi＝(QgiμgL)/(kA△Pi)
in the formula: swiThe water saturation of the rock core at the time t is shown; p1iThe pressure at the inlet end of the rock core at the time t is Pa; p1iThe pressure at the outlet end of the rock core at the time t is Pa; delta PiThe pressure difference between two ends of the rock core at the time t, Pa; qwiIs the stratum water flow at time t, m3/s；QgiIs the gas flow at time t, m3S; k is the absolute permeability of the core, m2；KrwiAs the water saturation SwiRelative permeability of the aqueous phase; krgiAs the water saturation SwiThe relative permeability of the gas phase at the time of treatment,
3) when the reading of the electronic balance b no longer changes, i.e. the water saturation in the core has reached the irreducible water saturation Swc1Continuously measuring the pressure difference and the gas flow under the three groups of irreducible water saturation, calculating the phase permeability of the gas phase until the relative error is less than 3%, and calculating the irreducible water saturation S of the first gas water flooding of the rock core according to the recorded mass of the water of the expelled stratumwc1；
Swc1＝(Gw-Gwit)/Gw
In the formula: gwitIn order to drive out the total mass of formation water, kg,
4) the displacement pump was turned off, valve 6 of hex valve a and valve 6 of hex valve b were opened to vent the system, and then all valves were closed.
Step S4, simulating a gas production working process of a gas storage by a water-flooding experiment:
1) the pipeline that will carry out the water drive gas experiment is vacuumized, avoids detaining the interference of gas, stratum water in the pipeline to the experimental result:
2) displacing formation water flow Q as designedwjArranging a displacement pump and starting the displacement pump to enable formation water to enter the rock core from the end b of the rock core holder, driving gas in the rock core out of the end a of the rock core holder to a drying pipe b, recording high-precision gas flowmeter data within n seconds in real time, and obtaining average gas flow QgjSimultaneously recording average values P of readings of pressure sensors at the inlet end and the outlet end of the rock core within n seconds1jAnd P2jCalculating the pressure difference delta P between two ends of the rock corejAccording to displacement pump driveCalculating the formation water mass pumped into the core according to the time (n seconds) of the displacement, thereby calculating the water saturation S of the corewjCalculating the relative permeability of gas and formation water under the water saturation according to the gas flow, the formation water flow and the core absolute permeability (each expelled formation water quality can calculate a water saturation value, and correspondingly calculate a gas flow and a pressure difference), and at least acquiring more than 7 groups of data to ensure that the relative permeability curve form is relatively smooth;
Swj＝Swc1+(nρwQwj)/Gw
△Pj＝P1j-P2j
Krwj＝(QwjμwL)/(kA△Pj)
Krgj＝(QgjμgL)/(kA△Pj)
3) when the reading of the gas meter no longer changes, i.e. the gas saturation in the core has reached the residual gas saturation Sgr1Continuously measuring the pressure difference and the formation water flow under the three groups of residual gas saturation, calculating the phase permeability of the water phase until the relative error is less than 3%, and calculating the residual gas saturation S of the first water flooding of the rock core according to the recorded quality of the pumped formation watergr1；
Sgr1＝1-Swc1-TQwj
In the formula: sgr1Residual gas saturation for the first water purge; t is the experimental time, s, n is the time, s,
4) the displacement pump was turned off, valve 6 of hex valve a and valve 6 of hex valve b were opened to vent the system, and then all valves were closed.
Step S5, drawing a gas-water relative permeability curve of one injection-production period
And establishing a rectangular coordinate system by taking the water saturation value of the rock core as a horizontal coordinate and the relative permeability value as a vertical coordinate, and respectively drawing a gas phase relative permeability curve and a water phase relative permeability curve corresponding to different water saturations of the rock core by adopting smooth curves.
In the experiment process, a pipeline between the outlet end of the core holder and the drying pipe needs to be replaced by soap water for several times before the experiment, so that the influence of capillary force on the movement of formation water is reduced as much as possible; the placing height of the drying tube and the electronic balance is required to be equal to that of the core holder so as to eliminate the influence of gravity on the movement of formation water.
The invention provides a preferable measuring system structure, the invention is not limited to the measuring system, the main purpose of the invention is to provide a method for testing a relative permeability curve, and any system capable of simultaneously carrying out a gas-water driving experiment and a water-gas driving experiment can be used as an experimental basis for implementing the measuring method of the invention.
Embodiment 2:
Specifically, in the gas-driven water pipeline, gas enters from a first end (end a of the core holder) of the core holder and is output from a second end (end b of the core holder) of the core holder; in the water-driven gas pipeline, formation water enters from the second end (the b end of the core holder) of the core holder and is output from the first end (the a end of the core holder) of the core holder. When the water flooding experiment of step S4 is performed by using the system shown in fig. 1, the following steps are performed:
1) opening valves 1, 3 and 5 of a hexagonal valve a, valves 2 and 3 of a three-way valve a, valves 1 and 2 of a three-way valve b, valves 2 and 3 of a hexagonal valve b, a valve f and a valve j, opening a vacuum pump, observing the vacuum meter a and the vacuum meter b, closing the vacuum pump after the displacement system pipeline and the valve are vacuumized, closing the valves 3 of the hexagonal valve a, the valves 3 and f and the valves j of the hexagonal valve b, and opening valves a, c, e, a back-pressure valve a and valves 4 of the hexagonal valve b;
2) displacing formation water flow Q as designedwjArranging a displacement pump and starting the displacement pump to enable formation water to enter the rock core from the end b of the rock core holder and to enable the formation water to enter the rock coreThe gas is driven out of the end a of the rock core holder to a drying pipe b, the data of the high-precision gas flowmeter within n seconds is recorded in real time, and the average gas flow Q is obtainedgjSimultaneously recording average values P of readings of pressure sensors at the inlet end and the outlet end of the rock core within n seconds1jAnd P2j(in this case, the pressure sensor b is an inlet end pressure sensor, and the pressure sensor a is an outlet end pressure sensor), and the differential pressure deltaP between two ends of the rock core is calculatedjCalculating the formation water mass pumped into the core according to the displacement time (n seconds) of the displacement pump, thereby calculating the water saturation S of the corewjAnd calculating the relative permeability of the gas and the formation water under the water saturation according to the gas flow, the formation water flow and the core absolute permeability (each expelled formation water mass can be used for calculating a water saturation value, and correspondingly calculating a gas flow and a pressure difference), and at least acquiring more than 7 groups of data to ensure that the relative permeability curve form is relatively smooth.
Embodiment 3:
under the multi-cycle injection-production working condition, the gas-water two-phase seepage rule changes along with the progress of the injection-production cycle and is not invariable. In order to accurately analyze the conditions in each injection-production cycle and improve the accuracy of the measurement process, the present embodiment differs from embodiments 1 and 2 only in that steps S3 to S5 in embodiments 1 and 2 are repeated to complete the gas-water flooding permeability test for a plurality of cycles and obtain a multi-cycle mutually flooding gas-water relative permeability curve.
The above description is only a preferred embodiment of the present invention, and not intended to limit the present invention, the scope of the present invention is defined by the appended claims, and all structural changes that can be made by using the contents of the description and the drawings of the present invention are intended to be embraced therein.
Claims (10)
1. A method for measuring a gas-water relative permeability curve is characterized by comprising the following steps:
1) saturating formation water with a core to be tested;
2) calculating the displacement pressure of the gas drive and the displacement flow of the water drive according to the environment outside the source of the rock core to be detected;
3) performing a gas flooding experiment:
injecting gas into the core to be tested according to the displacement pressure of the gas drive, and measuring the mass/flow of the expelled formation water and the gas flow in real time; further calculating the relative permeability of the gas phase and the relative permeability of the water phase in the gas flooding process;
4) performing a water flooding experiment:
according to the displacement flow of the water drive, injecting formation water into the core to be tested, measuring the gas flow driven out by the water drive in real time, and calculating the relative permeability of the gas phase and the relative permeability of the water phase in the water drive process according to the displacement flow and the gas flow driven out by the water drive;
5) a gas phase relative permeability curve and a water phase relative permeability curve were constructed.
2. The method for determining the gas-water relative permeability curve as claimed in claim 1, wherein in the gas flooding experiment, gas is injected from one side of the core to be measured, and in the water flooding experiment, formation water is injected from the other side of the core to be measured.
3. The method for measuring the gas-water relative permeability curve according to claim 1, wherein the steps 3) to 5) are repeated to obtain a multi-cycle gas-phase relative permeability curve and a multi-cycle water-phase relative permeability curve.
4. The method for determining the gas-water relative permeability curve according to claim 1, wherein the step 2) further comprises calculating confining pressure, and performing a gas flooding experiment and a water flooding experiment under the confining pressure; the confining pressure is greater than the displacement pressure.
5. The method for determining the gas-water relative permeability curve according to claim 1, wherein the steps 3) and 4) further comprise the step of vacuumizing the experiment pipeline before the experiment.
6. The method for determining the gas-water relative permeability curve according to claim 1, wherein in the step 2), the calculation formulas of the relative permeability of the gas phase, the relative permeability of the water phase and the irreducible water saturation are as follows:
Swi＝(Gw-Gwi)/Gw
△Pi＝P1i-P2i
Qwi＝Gwi/ρw
Krwi＝(QwiμwL)/(kA△Pi)
Krgi＝(QgiμgL)/(kA△Pi)
Swc1＝(Gw-Gwit)/Gw
in the formula: swiThe water saturation of the rock core at the time t in the gas flooding process is shown; gwiThe average value of the quality of the formation water continuously driven out for n seconds in the gas drive process; gwThe wet weight of the core under normal pressure; p1iThe average pressure at the inlet end of the rock core at the time t in the gas flooding process is shown; p1iThe pressure of the outlet end of the rock core at the time t in the gas flooding process is shown; delta PiThe pressure difference between two ends of the rock core at the time t in the gas flooding process; qwiThe formation water flow at the time t in the gas flooding process; qgiThe gas flow at the time t in the gas flooding process; k is the absolute permeability of the rock core; krwiAs the water saturation SwiRelative permeability of the aqueous phase; krgiAs the water saturation SwiRelative permeability of the gas phase; swc1Irreducible water saturation; gwitIs the total mass of formation water displaced during the gas flooding process.
7. The method for determining the gas-water relative permeability curve according to claim 6, wherein in the step 3), the calculation formula of the relative permeability of the gas phase and the relative permeability of the water phase is as follows:
Swj＝Swc1+(nρwQwj)/Gw
△Pj＝P2j-P1j
Krwj＝(QwjμwL)/(kA△Pj)
Krgj＝(QgjμgL)/(kA△Pj)
wherein S iswjThe water saturation, Q, of the rock core in the water flooding processgjIs the average gas flow, Q, in the water flooding processwjDisplacement flow for water flooding, Swc1The irreducible water saturation of the gas flooding water and n is the time.
8. The method for determining the gas-water relative permeability curve as claimed in claim 7, wherein the step 4) further comprises calculating the saturation of the residual gas according to the saturation of the irreducible water and the displacement flow, and the calculation formula is as follows:
Sgr1＝1-Swc1-TQwj
in the formula: sgr1The residual gas saturation in the water flooding process; t is the experimental time.
9. A gas-water relative permeability curve determination system, comprising:
the core holder is used for holding a core to be measured;
the displacement pump is used for providing displacement power;
the gas drive water pipeline is connected with the displacement pump and the rock core holder and is used for carrying out a gas drive water experiment;
the water drive gas pipeline is connected with the displacement pump and the core holder and is used for performing a water drive gas experiment;
the gas flowmeter is arranged at the downstream of the gas drive water pipeline and the water drive gas pipeline and is used for detecting the gas flow;
and the formation water quality/flow detector is arranged at the downstream of the gas drive water pipeline and the water drive gas pipeline and is used for detecting the formation water quality/flow.
10. The system for determining a gas-water relative permeability curve of claim 9, wherein in the gas flooding water line, gas enters from a first end of the core holder and is output from a second end of the core holder; in the water-driven gas pipeline, formation water enters from the second end of the core holder and is output from the first end of the core holder.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116539815A (en) * | 2023-06-07 | 2023-08-04 | 四川省科源工程技术测试中心有限责任公司 | Device and method suitable for evaluating and optimizing working fluid of oil and gas reservoir |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103954544A (en) * | 2014-05-13 | 2014-07-30 | 中国石油大学(北京) | Experimental device and method for estimating water-controlling and air-intake effects of polymer |
| CN104568694A (en) * | 2014-12-19 | 2015-04-29 | 西南石油大学 | Method for testing gas-water relative permeability of dense core |
| CN106124377A (en) * | 2016-06-16 | 2016-11-16 | 中海石油(中国)有限公司上海分公司 | The experimental test procedures of gas reservoir reverse osmosis water suction lock damage evaluation under high-temperature and high-pressure conditions |
| CN106525690A (en) * | 2016-12-02 | 2017-03-22 | 中国石油天然气股份有限公司 | Method for measuring gas-water relative permeability curve by tight sandstone steady-state method |
| CN206410978U (en) * | 2017-01-18 | 2017-08-15 | 西南石油大学 | A kind of tight rock gas phase relative permeability measurement apparatus |
| CN206609743U (en) * | 2017-04-06 | 2017-11-03 | 重庆科技学院 | Water drive gas reservoir water enchroachment (invasion) dynamic holdup loses experiment test system |
| CN108896599A (en) * | 2018-05-16 | 2018-11-27 | 重庆科技学院 | A kind of system and method for testing Gas And Water Relative Permeability curve |
| CN208171813U (en) * | 2018-03-16 | 2018-11-30 | 西南石油大学 | A kind of multi-functional permeability test device |
| CN109916799A (en) * | 2019-03-22 | 2019-06-21 | 西南石油大学 | Measure the experimental method of the spontaneous Imbibition Relative Permeability of unconventional tight gas reservoir |
| CN110231266A (en) * | 2019-03-15 | 2019-09-13 | 广州海洋地质调查局 | Gas And Water Relative Permeability measuring method under different stress difference hydrate saturation states |
-
2020
- 2020-06-24 CN CN202010590908.8A patent/CN113834762A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103954544A (en) * | 2014-05-13 | 2014-07-30 | 中国石油大学(北京) | Experimental device and method for estimating water-controlling and air-intake effects of polymer |
| CN104568694A (en) * | 2014-12-19 | 2015-04-29 | 西南石油大学 | Method for testing gas-water relative permeability of dense core |
| CN106124377A (en) * | 2016-06-16 | 2016-11-16 | 中海石油(中国)有限公司上海分公司 | The experimental test procedures of gas reservoir reverse osmosis water suction lock damage evaluation under high-temperature and high-pressure conditions |
| CN106525690A (en) * | 2016-12-02 | 2017-03-22 | 中国石油天然气股份有限公司 | Method for measuring gas-water relative permeability curve by tight sandstone steady-state method |
| CN206410978U (en) * | 2017-01-18 | 2017-08-15 | 西南石油大学 | A kind of tight rock gas phase relative permeability measurement apparatus |
| CN206609743U (en) * | 2017-04-06 | 2017-11-03 | 重庆科技学院 | Water drive gas reservoir water enchroachment (invasion) dynamic holdup loses experiment test system |
| CN208171813U (en) * | 2018-03-16 | 2018-11-30 | 西南石油大学 | A kind of multi-functional permeability test device |
| CN108896599A (en) * | 2018-05-16 | 2018-11-27 | 重庆科技学院 | A kind of system and method for testing Gas And Water Relative Permeability curve |
| CN110231266A (en) * | 2019-03-15 | 2019-09-13 | 广州海洋地质调查局 | Gas And Water Relative Permeability measuring method under different stress difference hydrate saturation states |
| CN109916799A (en) * | 2019-03-22 | 2019-06-21 | 西南石油大学 | Measure the experimental method of the spontaneous Imbibition Relative Permeability of unconventional tight gas reservoir |
Non-Patent Citations (2)
| Title |
|---|
| JIAN SHEN ET.AL: "Relative permeabilities of gas and water for different rank coals", 《INTERNATIONAL JOURNAL OF COAL GEOLOGY》, 31 December 2011 (2011-12-31), pages 266 - 275 * |
| 章星 等: "火山岩气藏气水两相渗流特征分析", 《断 块 油 气 田》, vol. 20, no. 5, 30 September 2013 (2013-09-30), pages 631 - 633 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116539815A (en) * | 2023-06-07 | 2023-08-04 | 四川省科源工程技术测试中心有限责任公司 | Device and method suitable for evaluating and optimizing working fluid of oil and gas reservoir |
| CN116539815B (en) * | 2023-06-07 | 2024-03-19 | 四川省科源工程技术测试中心有限责任公司 | Device and method suitable for evaluating and optimizing working fluid of oil and gas reservoir |
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