CN107727834B

CN107727834B - Simulation experiment method for water soluble gas transportation

Info

Publication number: CN107727834B
Application number: CN201711141627.9A
Authority: CN
Inventors: 张军龙; 李建军
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-07-21
Filing date: 2016-07-21
Publication date: 2020-05-12
Anticipated expiration: 2036-07-21
Also published as: CN106053764A; CN106053764B; CN108169460A; CN108169460B; CN107727834A

Abstract

The invention discloses a simulation experiment method for water soluble gas migration, which uses a simulation device for simulating the migration of water soluble gas in a self-generation and self-storage syncline-structured basin to carry out a simulation experiment, wherein the simulation experiment comprises the following steps: 1) before starting the experiment, all valves of the simulation device are closed; 2) opening a vacuum pump valve and a vacuum pump, and continuously vacuumizing the reservoir simulation system until residual gas does not exist in the sample in the reservoir simulation system; 3) opening a pressure valve of the high-pressure gas cylinder to be detected, adjusting a pressure reducing valve, setting gas supply pressure, continuously supplying gas until the readings of all gas pressure meters are stable, and closing the pressure valve; 4) stably injecting water into a simulation pipeline of the reservoir simulation system, enabling liquid in the first drainage pipe to reach a gas-liquid separator, and realizing gas-liquid separation in the gas-liquid separator; 5) gas sample collection: sequentially collecting gas samples at a plurality of sampling points; 6) and (5) repeating the step 5) to sample until the next sampling time, and circulating the steps till the sampling is finished. The simulation test method adopted by the invention is accurate, simple and feasible, and provides basic theoretical support for the development of the coal bed gas/shale gas.

Description

Simulation experiment method for water soluble gas transportation

The application is a divisional application of an invention patent application with the application number of 201610579573.3, the application date of 2016, 7 and 21 and the name of 'simulation experiment method for water-soluble gas migration from self-generation to self-storage to inclined structured basin'.

Technical Field

The invention relates to a simulation experiment method for migration of water-soluble gas, in particular to a simulation experiment method for migration capacity of water-soluble gas (simply called water-soluble gas) of unconventional natural gas storage syncline structure basin stratum and a mechanism of fractionation of the water-soluble gas on carbon isotopes of reservoir gas, and belongs to the technical field of migration rule and isotope fractionation of the water-soluble gas in a solid, liquid and gas three-phase mixed medium of low-permeability self-generated unconventional natural gas (such as coal bed gas/shale gas) syncline structure basin.

Background

At present, the contribution of water-soluble gas to unconventional natural gas reserves is paid attention, hydrocarbon gas dissolved in formation water is called water-soluble gas simply, and the water-soluble gas is actually one of important forms of occurrence states of unconventional natural gas (including coal bed gas/shale gas). The unconventional natural gas is associated with formation water all the time in the process of generating and transporting the unconventional natural gas into a reservoir, and the formation water can have a fractionation effect on components and carbon isotopes of the unconventional natural gas, which can also be a reason for lightening the carbon isotopes of the unconventional natural gas (such as coal bed gas). But how does water-soluble gas affect the distribution of reservoir basin air content? How does the mechanism of isotopic fractionation of reservoir gas carbon after flowing formation water dissolution and transport of reservoir gas? These problems are all under investigation. Therefore, the indoor physical simulation device is designed to simulate the geometric characteristics of the section of the unconventional natural gas (coal bed gas/shale gas) storage syncline structure basin and the flowing characteristics of underground water, study the gas dissolving capacity in the flowing process of the underground water and the influence on the stable isotope fractionation of the gas, and provide data support for the research of the formation and cause of the coal bed gas.

The unconventional natural gas (coal bed gas/shale gas) has the characteristics of self-generation and self-storage, and a typical geological structure which is favorable for the unconventional natural gas is a syncline structure or a wing of the syncline structure, the common form of the syncline structure is that two wings are tilted, the middle part is relatively flat, the groundwater in the basin is supplied as a two-wing aquifer outcrop, then the groundwater in the basin flows along the aquifer to the middle part of the basin, and overflows from a wing with a lower relative elevation of the aquifer outcrop under the action of head pressure difference, the overflow end is called a drainage area, a wing with a higher relative elevation is called a supply area, and a pressure bearing area is called between the two-wing water level elevation connecting lines, as shown in figure 1, for the self-generation and self-storage unconventional natural gas (comprising coal bed gas/shale gas) reservoir basin, the two wings can be divided into types according to the inclination degree of the reservoir, generally can be divided into a near horizontal section (α is not more than 5 degrees), a slow inclined section (5 degrees is not more than α not more than 15 degrees), an inclined section (15 degrees is not more than α degrees, a steep inclined section (α is more than 35).

Disclosure of Invention

The invention aims to solve the technical problem of providing a simulation device or research method for migration capacity of water-soluble gas (simply called water-soluble gas) of a stratum of an unconventional natural gas storage syncline structure basin and influence of the water-soluble gas on carbon isotope fractionation of reservoir gas, which can simulate the migration rule of the water-soluble gas in a solid, liquid and gas three-phase mixed medium of the low-permeability self-stored unconventional natural gas (such as coal bed gas/shale gas) syncline structure basin, the gas content distribution of the water-soluble gas on the reservoir gas and the gas isotope fractionation, and can also complete a gas dissolution capacity simulation experiment and a seepage simulation experiment of the three-phase medium.

In order to solve the technical problems, the technical scheme adopted by the invention comprises the following steps: reservoir simulation system, water supply system, gas-liquid recovery system, sample collection system, saturation and vacuum-pumping system, lift by crane control system, constant temperature control system and relevant connecting line. The reservoir simulation system comprises 3 hollow simulation pipelines which are connected in sequence, the hollow simulation pipelines respectively correspond to two wings and a core area of the syncline structure, the length and the gradient of the hollow simulation pipelines are manufactured according to a certain similarity ratio according to the section shape of a prototype basin, and the hollow simulation pipelines are used for simulating indoor simulation tests of water-soluble gas migration rule, water-soluble gas isotope fractionation rule, gas dissolving capacity, seepage of three-phase medium and the like in solid, liquid and gas three-phase mixed medium of the syncline structure basin of low-permeability autogenous unconventional natural gas (such as coal bed gas/shale gas). One end of the simulation pipeline is connected with a water supply system, and a sampling pipe is led out at the same time, so that the water supply system can provide a stable water pressure field and constant water flow for the reservoir simulation system; the other end is connected with a gas-liquid recovery system which can be used as 1 sampling pipe at the same time, and the gas-liquid recovery system is responsible for collecting gas and liquid flowing out of the reservoir simulation system. In order to prepare and sample in the middle of the test earlier stage, 2 sampling pipes are arranged at the middle interconnection part of the simulation pipeline, and each sampling pipe is divided into two parts which are respectively connected with a saturation and vacuum-pumping system and a sample collection system. According to research needs, sampling pipes can be led out from the gradient change parts of the two-wing simulation pipeline at the same time and are connected with a sample collection system. The saturation and vacuum-pumping system can enable the sample in the simulation pipeline to form a gas-containing saturated state, simulate a self-generated gas-containing saturated reservoir and restore an original uniform gas-containing reservoir. The sample collection system can collect samples of different sampling points of the simulation pipeline according to design requirements, is used for analyzing the change of sample attributes in the simulation process, and provides data support for subsequent research. The lifting control system comprises a fixing frame and a lifting device, the fixing frame is suspended below the lifting device and used for fixing 3 simulation pipelines and part of sampling pipelines of the reservoir simulation system, the reservoir simulation system is flexibly connected with other systems through a hose, the lifting device is convenient to lift and drop the reservoir simulation system, and the simulation pipelines are immersed below the liquid level of a thermostat of the constant temperature control system or are lifted above the liquid level. The thermostatic control system provides a constant temperature field for the reservoir simulation system.

In order to realize the purpose of the invention, the following technical scheme is adopted for realizing the purpose:

a simulation experiment method for water soluble gas migration uses a simulation device for water soluble gas migration of a self-generated and self-stored syncline-structured basin to perform an experiment, wherein the experiment method comprises a simulation experiment step which comprises the following steps:

1) before starting the experiment, all valves of the simulation device are closed;

2) opening a vacuum pump valve and a vacuum pump, continuously vacuumizing the reservoir simulation system until no residual gas exists in the sample in the reservoir simulation system, and entering the next step;

3) opening a pressure valve of a high-pressure gas cylinder to be detected, adjusting a pressure reducing valve, setting gas supply pressure P (the gas supply pressure P is (1.2-1.5) P, the P is the hydrostatic pressure of a reservoir in the prototype basin, the P is gamma h, the gamma is the gravity of water, and the h is the buried depth of the reservoir), continuously supplying gas until the readings of all gas gauges are stable, closing the pressure valve, and entering the next step; simultaneously recording the numerical values of the gas mass flowmeter and the barometer;

4) opening a water supply valve, adjusting a constant pressure valve, opening a water supply pump, stably injecting water into a simulation pipeline of a reservoir simulation system by the water supply pump at a level slightly higher than the hydrostatic pressure p (p is gamma h, wherein gamma is the gravity of water, and h is the reservoir burial depth), enabling liquid in a first drainage pipe to reach a gas-liquid separator, realizing gas-liquid separation in the gas-liquid separator, discharging gas through a valve on a gas recovery pipeline, collecting the gas by a recovery container, enabling the liquid to flow through an overflow chamber, and collecting the liquid by a liquid recovery container;

5) gas sample collection: sequentially collecting gas samples at a plurality of sampling points;

6) and (5) repeating the step 5) to sample until the next sampling time, and circulating the steps till the sampling is finished.

The experimental method preferably comprises the following steps: step 5) of the simulation experiment step includes: determining sampling time interval according to test requirements, and then sequentially collecting gas samples at a first sampling point to a fourth sampling point, wherein,

when a sample at a first sampling point is collected, closing a liquid recovery valve, opening a valve on a second drainage pipeline, standing for a certain time, observing side scales of a gas-liquid separation bottle, recording the time for generating a certain volume of gas, recording the reading of a temperature sensor, opening a gas collection valve, collecting a gas sample, numbering the gas sample, closing the valve on the first sampling pipeline and the valve on the second drainage pipeline, opening a valve on a water supply pipe, refilling a gas-liquid separator and a gas pressure balance bottle with liquid, enabling the top of the gas-liquid separator to be full of the liquid without leaving a gap, closing the valve of the water supply pipe, and finishing sampling at the first sampling point;

when a sample at a second sampling point is collected, a valve on a second sampling pipeline and a valve on a first drainage pipeline are opened, liquid flowing out from the second sampling point is discharged for a period of time, the valve on the first drainage pipeline is closed, the valve on the second drainage pipeline is opened, standing is carried out for a certain time, the side scale of a gas-liquid separation bottle is observed, the time for generating a certain volume of gas is recorded, the reading of a temperature sensor is recorded, a gas collection valve is opened, a gas sample is collected, the gas sample is numbered, the valve on the second sampling pipeline and the valve on the second drainage pipe are closed, the valve on a water supply pipe is opened, the gas-liquid separator and the gas pressure balance bottle are refilled with liquid, no gap is left at the top after the gas-liquid separator is filled with the liquid, the valve of the water supply pipe is closed;

when a sample at a third sampling point is collected, a valve on a third sampling pipeline and a valve on a first drainage pipeline are opened, liquid flowing out from the third sampling point is discharged for a period of time, the valve on the first drainage pipeline is closed, a valve on a second drainage pipeline is opened, standing is carried out for a certain time, the side scale of a gas-liquid separation bottle is observed, the time for generating a certain volume of gas is recorded, the reading of a temperature sensor is recorded, a gas collection valve is opened, a gas sample is collected, the gas sample is numbered, the valve on the third sampling pipeline and the valve on the second drainage pipe are closed, the valve on a water supply pipe is opened, a gas-liquid separator and a gas pressure balance bottle are refilled with liquid, no gap is left at the top after the gas-liquid separator is filled with the liquid, the valve of the water supply pipe is closed;

when the sample of the fourth sampling point department is gathered, open the valve on the fourth sampling pipeline and the valve on the first drainage pipeline, make the liquid that the fourth sampling point department flows discharge a period of time, close the valve on the first drainage pipeline, open the valve on the second drainage pipeline, a certain time stews, observe gas-liquid separation bottle side scale, the record generates the time that certain volume gas used, record temperature sensor's reading, open the gas collection valve, collect the gas sample, to gas sample serial number, close the valve on the fourth sampling pipeline and the valve on the second drainage pipe, open the valve on the delivery pipe, annotate gas-liquid separator and gas pressure balance bottle again with liquid, make gas-liquid separator full of liquid back top not leave the space, close the delivery pipe valve, the fourth sampling point sampling finishes.

The experimental method preferably comprises the following steps: the step of simulating the experiment further comprises step 7): changing the experimental conditions, including one or the combination of the granularity, the porosity, the gas supply medium, the liquid medium, the water pressure, the water flow speed and the temperature of the porous solid medium filling the sample, and carrying out the experiment again according to the experimental steps 1) to 6).

The experimental method preferably comprises the following steps: the step 2) in the simulation experiment step is specifically as follows:

opening a vacuum pump valve and a vacuum pump, continuously vacuumizing the reservoir simulation system for more than 6-8 hours, then closing, standing for more than 3-5 hours, checking readings of the first barometer to the fourth barometer on the first sampling pipeline to the fourth sampling pipeline, checking whether the readings of all the barometers are stable, if not, continuously vacuumizing, checking again, repeating the steps until the readings of the barometers are stable, and entering the next step of the experiment.

The experimental method preferably comprises the following steps: the step 3) in the simulation experiment step is specifically as follows:

switching a high-pressure air supply source into a high-pressure air bottle to be tested, opening a pressure valve on a main air supply pipeline, opening air supply valves on a first air supply branch and a second air supply branch, adjusting a pressure reducing valve, and setting air supply pressure P; filling coal bed gas into a simulation pipe of the reservoir simulation system, continuously injecting for a preset time, closing a pressure valve on a main gas supply pipeline, standing for a period of time, continuously observing readings of all barometers, and entering the next step if the readings are stable; and if the reading of any barometer is reduced, the pressure valve on the main gas supply pipeline is opened again, the coal bed gas is continuously filled into the simulation pipe of the reservoir simulation system, the steps are repeated until the readings of all the barometers are stable, the pressure valve on the main gas supply pipeline is closed, the next step of the experiment is carried out, the gas mass flow meter and all the gas pressure representation values are recorded simultaneously, and the accumulated filling quality of the gas to be measured of the system and the balanced gas supply pressure are determined.

The experimental method preferably comprises the following steps: the method also comprises a pre-experiment preparation step, wherein the pre-experiment preparation step comprises the following steps:

1) dividing the length and the gradient of a section segment according to the stratum prototype section, and determining the type of the section;

2) calculating the length of the section of the simulation pipeline, the distance between the simulation pipelines and the combination relation;

3) manufacturing a simulation pipeline and connecting the simulation pipeline;

4) debugging a sample collection system and a gas-liquid recovery system;

5) checking air tightness;

6) and (5) simulating pipeline sample loading.

The experimental method preferably comprises the following steps:

the preparation steps before the experiment specifically comprise the following steps:

1) according to the stratum prototype section, dividing the length and the gradient of the section segment, and determining the type of the section: extracting main gradient types, lengths and combination relations of the characteristic profile features, and determining the lengths of the main gradient types;

2) calculating the length of the section of the simulation pipeline, the distance of the simulation pipeline and the combination relation: determining a simulation geometric similarity ratio, determining the segment length and the simulation pipeline interval of a simulation pipeline corresponding to the reservoir simulation system according to the simulation geometric similarity ratio, and specifically calculating according to formulas (1) to (3):

s＝l_i/l_{original i}＝L_i/L_{Original i}＝b/B_{Original source}(1)

sinα_i＝h_i/l_i(2)

sinβ_i＝H_j/L_j(3)

In the formula: s is the geometric similarity ratio of the model to the prototype;

l_{original i}、L_{Original i}Segment lengths of the supply side and the discharge side of the prototype basin, respectively;

b、B_{original source}Respectively the lengths of the syncline basin model and the approximate horizontal segment of the prototype nuclear part;

α_i、β_irespectively counting median for the sectional slopes of the supply side and the drainage side of the prototype basin;

h_i、l_irespectively determining the spacing and the segment length of the simulation pipelines for the basin supply side according to the similarity ratio;

H_j、L_jthe simulation pipeline spacing and the segment length are determined according to the similarity ratio for representing the drainage side of the basin;

i and j are natural numbers and respectively represent the number of sections of the basin supply side model pipeline and the basin drainage side model pipeline;

3) manufacturing a section simulation pipeline and connecting the section simulation pipeline with the simulation pipeline: after the first to third steps of simulation pipelines with corresponding lengths and gradients are manufactured, the simulation pipelines are connected according to the combination relationship of section types and are respectively fixed on two vertical fixing frames and a horizontal fixing frame, wherein the first simulation pipeline and the second simulation pipeline are respectively fixed on the two vertical fixing frames, the third simulation pipeline is fixed on the horizontal fixing frame, two ends of the horizontal fixing frame are respectively connected with the bottoms of the two vertical fixing frames, after the two vertical fixing frames are combined with a hoisting cross beam, the hoisting cross beam is hung on a hoisting device, and then a reservoir simulation system is sequentially connected with other systems;

4) opening a valve on a water supply pipe, filling water into containers of a gas-liquid separator and a gas pressure balance bottle of the sample collection system, leaving no gap on the top of the gas-liquid separator after the gas-liquid separator is filled with water, and closing the valve of the water supply pipe; the gas-liquid separator of the gas-liquid recovery system is filled with water in advance, or the water filling height at least submerges the pipe end of the first drainage pipe;

5) and (3) checking air tightness: firstly, selecting nitrogen from a high-pressure gas supply source, opening a gas supply valve, adjusting a pressure reducing valve, setting the pressure in a simulation pipeline of a reservoir simulation system as a test pressure W (the test pressure W is (1.5-2) p, and the system pressure p is gamma h according to the hydrostatic pressure p of a reservoir in a prototype basin, wherein gamma is the gravity of water, and h is the reservoir burial depth), and checking the tightness of the device;

6) simulation pipeline sample loading: hoisting the simulation pipeline to a position above the liquid level of the incubator by a hoisting device, selecting a pre-prepared coal rock sample, filling the first simulation pipeline, the second simulation pipeline and the third simulation pipeline in a segmented manner, reconnecting the simulation pipeline connector and the connecting pipeline after the coal rock sample is filled, ensuring the sealing to be complete, and then completely immersing the first simulation pipeline to the third simulation pipeline below the liquid level of the incubator by the hoisting device to start a simulation experiment.

The experimental method preferably comprises the following steps: the step of connecting the reservoir simulation system with other systems in sequence in step 3) of the preparation step before the experiment comprises the following steps:

the upper end of the first simulation pipeline is connected with a water supply pipe and then is connected with a water supply system, and the upper end of the pipeline is simultaneously used as a fourth sampling point and is connected with a fourth inlet port of the connector through a fourth sampling pipeline; the upper end of the second simulation pipeline is used as a first sampling point and is connected with a first inlet port of the connector through a first sampling pipeline; the joint of the first simulation pipeline and the third simulation pipeline is used as a third sampling point to lead out a branch pipeline, and the branch pipeline is divided into two parts and is respectively connected with a third inlet port of the connector and a saturation and vacuum pumping system; the joint of the second simulation pipeline and the third simulation pipeline is used as a second sampling point and led out of a branch pipeline, and the branch pipeline is divided into two parts and is respectively connected with a second inlet port of the connector and a saturation and vacuum-pumping system; the outlet port of the connector is connected with the gas-liquid recovery system and the sample collection system through the drainage pipe.

The experimental method preferably comprises the following steps: the step of simulating the experiment further comprises a sample testing and data analyzing step, the sample testing and data analyzing step comprising:

and carrying out component test and isotope test on the collected sample, researching sample components and isotope change at different sampling intervals, and researching the influence of groundwater flow on the isotope fractionation of reservoir gas.

A simulation experiment method for water soluble gas migration, which uses a simulation device for water soluble gas migration of a self-generated and self-stored syncline-structured basin to perform an experiment, comprises a simulation experiment step, and comprises the following steps:

2) opening a water supply valve, adjusting a constant pressure valve, opening a water supply pump, stably injecting water into a simulation pipeline of the reservoir simulation system by the water supply pump at a level slightly higher than the hydrostatic pressure p of the reservoir in the prototype basin, enabling liquid in a first drainage pipe to reach a gas-liquid separator, realizing gas-liquid separation in the gas-liquid separator, discharging gas through a valve on a gas recovery pipeline, collecting the gas by a recovery container, and collecting the liquid by a liquid recovery container after the liquid flows through an overflow chamber;

3) gas sample collection: sequentially collecting gas samples at a plurality of sampling points;

4) and 3) repeating the step 3) to sample until the next sampling time, and circulating the steps till the sampling is finished.

The experimental method preferably comprises the following steps: the step 3) in the simulation experiment step includes: determining sampling time interval according to test requirements, and then sequentially collecting gas samples at a first sampling point to a fourth sampling point, wherein,

The experimental method, preferably the step of simulating the experiment, further comprises the step 5): changing experimental conditions including one or combination of physical parameters of reservoir sample, gas supply medium, liquid medium, water supply pressure, water supply flow and temperature

The experimental method preferably comprises a preparation step before experiment before the step of simulating experiment, wherein the preparation step before experiment comprises:

2) calculating the section length of the section simulation pipeline, the spacing of the simulation pipelines and the combination relation;

3) manufacturing a simulation pipeline and connecting the simulation pipeline;

4) debugging a sample collection system and a gas-liquid recovery system;

5) checking air tightness;

6) and (5) simulating pipeline sample loading.

The experimental method preferably comprises the following steps:

s＝l_i/l_{original i}＝L_i/L_{Original i}＝b/B_{Original source}(1)

sinα_i＝h_i/l_i(2)

sinβ_i＝H_j/L_j(3)

4) opening a valve on a water supply pipe, filling water into containers of a gas-liquid separator and a gas pressure balance bottle of the sample collection system, leaving no gap on the top of the liquid separator after the liquid separator is filled with water, and closing the valve of the water supply pipe; the gas-liquid separator of the gas-liquid recovery system is filled with water in advance, or the water filling height at least submerges the pipe end of the first drainage pipe;

5) and (3) checking air tightness: firstly, selecting nitrogen from a high-pressure gas supply source, opening a gas supply valve, adjusting a pressure reducing valve, setting the pressure in a simulation pipeline of a reservoir simulation system as a test pressure W, and checking the tightness of the device;

The experimental method preferably comprises the following steps: the step of sequentially connecting the reservoir simulation system with other systems in the step 3) of preparing before the experiment comprises the following steps:

the upper end of the first simulation pipeline is connected with a water supply pipe and then is connected with a water supply system, and the upper end of the pipeline is simultaneously used as a fourth sampling point and is connected with a fourth inlet port of the connector through a fourth sampling pipeline; the upper end of the second simulation pipeline is used as a first sampling point and is connected with a first inlet port of the connector through a first sampling pipeline; the joint of the first simulation pipeline and the third simulation pipeline is used as a third sampling point to lead out a branch pipeline, and the branch pipeline is connected with a third inlet port of the connector; the joint of the second simulation pipeline and the third simulation pipeline is used as a second sampling point and led out of a branch pipeline, and the branch pipeline is connected with a second inlet port of the connector; and after the pipeline connection is finished, filling fresh original gas-containing coal rock samples without desorbing coal bed gas into the first simulation pipeline to the third simulation pipeline, quickly crushing the newly collected original gas-containing coal rock samples, directly filling the crushed samples into the simulation pipeline of the reservoir simulation system, and entering the next step.

The experimental method preferably further comprises a sample testing and data analyzing step after the simulating step, wherein the sample testing and data analyzing step comprises the following steps:

sample testing and data analysis included: and carrying out component test and isotope test on the collected sample, researching sample components and isotope change at different sampling intervals, and researching the influence of groundwater flow on the isotope fractionation of reservoir gas.

In the above experimental method, the simulation device for water-soluble gas migration of the self-generating and self-storing syncline-structured basin is one of the following simulation devices:

a simulation device for water-soluble gas movement of a self-generating and self-storing syncline-structured basin comprises: reservoir simulation system, water supply system, gas-liquid recovery system, sample collection system, saturation and evacuation system, lift by crane control system and constant temperature control system, preferred:

the reservoir simulation system comprises a simulation pipeline, a plurality of sampling points are arranged on the simulation pipeline, the reservoir simulation system is placed in a constant temperature control system, and the constant temperature control system provides a preset working temperature for the reservoir simulation system;

the water supply system is connected with the reservoir simulation system through a pipeline and supplies water to the reservoir simulation system;

the gas-liquid recovery system and the sample collection system are both connected with the reservoir simulation system through pipelines to collect gas and liquid flowing out of the reservoir simulation system;

the saturation and vacuum-pumping system is connected with the reservoir simulation system through a pipeline, and is used for vacuumizing a sample filled in the reservoir simulation system and carrying out high-pressure gas saturation treatment;

the hoisting control system is used for hanging the reservoir simulation system so as to be placed in or hoisted out of the constant temperature control system.

The self-generation and self-storage syncline structure basin water soluble gas movement simulation device is preferably as follows:

the constant temperature control system comprises a constant temperature box and a temperature sensor, liquid is contained in the constant temperature box, the reservoir simulation device is soaked in the liquid in the constant temperature box, and the constant temperature box keeps the temperature of the liquid in the constant temperature box at a preset temperature according to the temperature information of the liquid in the constant temperature box, which is acquired by the temperature sensor.

the reservoir simulation system comprises a first simulation pipeline, a second simulation pipeline and a third simulation pipeline, the lower ends of the first simulation pipeline and the second simulation pipeline are mutually communicated through the third simulation pipeline, the upper ends of the first simulation pipeline and the second simulation pipeline are respectively provided with a fourth sampling point and a first sampling point, the fourth sampling point and the first sampling point are respectively connected with the sample collection system and the gas-liquid recovery system through connecting pipelines, and the fourth sampling point is connected with the water supply system through connecting pipelines; and a third sampling point and a second sampling point are respectively arranged at the joint of the first simulation pipeline and the third simulation pipeline and the joint of the second simulation pipeline and the third simulation pipeline, and any one of the third sampling point and the second sampling point is respectively connected with the sample collection system and the gas-liquid recovery system through the connecting pipeline and is connected with the saturation and vacuumizing system.

the lifting control system comprises a lifting cross beam, two vertical fixing frames, a horizontal fixing frame and a lifting device, wherein the two vertical fixing frames are respectively used for fixing a first simulation pipeline, a second simulation pipeline and a sampling point leading-out pipeline, and the horizontal fixing frame is used for fixing a third simulation pipeline; the two vertical fixing frames are respectively hung at the lower parts of the two sides of the lifting beam, the horizontal fixing frame is horizontally arranged at the bottoms of the two vertical fixing frames, the two ends of the horizontal fixing frame are respectively connected with the bottoms of the two vertical fixing frames, and the lifting beam is hung below the lifting device by the lifting device.

the water supply system comprises a water supply pump, a water pressure gauge, a water supply valve, a constant pressure valve and a water storage tank;

the water supply pump is connected with the reservoir simulation system through a water supply pipeline, a water supply valve and a water pressure meter are arranged between the water supply pipeline and the water supply pump, a constant pressure valve is arranged on a connecting pipeline between a connector and a first sampling point, the pressure of the reservoir simulation system is set by matching the water supply pump, and the pressure of the reservoir simulation system is set by matching the water supply pump. The water storage tank provides water source for the water supply pump.

and the water supply pump is connected with a fourth sampling point at the upper end of a first simulation pipeline of the reservoir simulation system through a water supply pipeline.

the liquid stored in the water storage tank is: basin formation water, deionized water or purified water.

the gas-liquid recovery system comprises a gas-pressure meter, a first drainage pipe, a valve, a gas-liquid separator, a gas recovery container and a liquid recovery container;

the gas-liquid separator is divided into a gas-liquid separation chamber and an overflow chamber, the gas-liquid separation chamber and the overflow chamber are communicated at the bottom, the top of the overflow chamber is provided with a hole, the overflow chamber is connected with a liquid recovery container through a pipeline, the top of the gas-liquid separation chamber is provided with two holes, one hole is communicated with the gas recovery container through a pipeline, a valve is arranged on the pipeline, the other hole is connected with an outlet port of a connector through a first drainage pipe, the first drainage pipe is provided with a valve, the end of the first drainage pipe is inserted into the gas-liquid separation chamber and is not more than 1/2 degrees of the gas-liquid separation chamber from the bottom of the gas-liquid separation chamber, and the distance from the bottom of the gas-liquid separation chamber to the.

The simulation device for the water-soluble gas migration of the self-generating and self-storing syncline-structured pot preferably further comprises a connector; wherein:

the connector is a pipeline connecting device with a plurality of inlet ports and an outlet port, and the inlet ports of the connector are respectively connected with a plurality of sampling points of a simulation pipeline of the reservoir simulation system through the pipeline; the outlet port of the connector is connected with a gas-liquid recovery system through a first drainage pipe, and a valve is arranged on the pipeline of the first drainage pipe; the outlet port of the connector is also connected with a sample collecting system through a second drainage pipe, and a valve is arranged on the pipeline of the second drainage pipe.

Preferably, one ends of the first drainage pipe and the second drainage pipe are connected with each other and then connected with an outlet port of the connector.

The self-generation and self-storage syncline structure basin water-soluble gas movement simulation device, a preferable sample collection system comprises a sample collection pipeline and a gas-liquid separation device, wherein:

the sample collection pipeline is a connecting pipeline between an inlet port of the connector and sampling points of the simulation pipeline, each pipeline is provided with a gas pressure gauge and a valve, the sample collection pipeline is used for collecting gas-liquid mixed samples at different parts of the reservoir simulation system, the collection pipelines at different sampling points are converged to the connector, are respectively connected with the corresponding inlet ports of the connector, and then are connected to the gas-liquid separation device through a second drainage pipeline by an outlet port of the connector;

the gas-liquid separation device comprises a valve, a gas-liquid separator, a gas pressure balance bottle, a gas collecting pipe and a temperature sensor;

the gas-liquid separator is a closed transparent container with an opening at the side surface of the lower part and an opening at the top, scales are marked on the side surface, a gas collecting pipe is arranged in one hole in the opening at the top, a gas collecting valve is arranged on the gas collecting pipe, and the pipe end of the gas collecting pipe is flush with the top of the container; the other hole is inserted with a second drainage pipe, a valve is arranged on the second drainage pipe, and the pipe end of the second drainage pipe is deeply inserted below the liquid level in the gas-liquid separator 27 and is not more than 1/3 from the bottom; the third hole is provided with a temperature sensor;

the gas pressure balance bottle is a transparent open container with 2 holes on the side surface, one hole is close to the upper part and is an overflow hole, and the height of the lower edge of the overflow hole is flush with the top of the gas-liquid separation bottle; the other hole is close to the bottom of the container, the height of the hole is the same as that of the hole on the side face of the bottom of the gas-liquid separation bottle, the other hole is communicated with the hole on the side face of the bottom of the gas-liquid separation bottle through a pipeline, a water supply pipe is placed in the gas pressure balance bottle, the other end of the water supply pipe is connected with a water storage tank, and a valve is arranged on the.

The self-generating and self-storing syncline structure basin water soluble gas movement simulation device is preferably as follows:

when the gas-liquid separator works, the gas-liquid separator and the gas pressure balance bottle are filled with water, the water level is the position of the lower edge of the overflow hole, and no gap is left at the top of the gas-liquid separator.

the saturation and vacuum-pumping system comprises a vacuum pump, a valve, a high-pressure gas supply source, a pressure valve, a pressure reducing valve, a barometer, a gas supply mass flowmeter and a tee joint;

the high-pressure gas supply source provides different kinds of gas according to the gas supply requirement;

a pressure valve, a pressure reducing valve, a barometer and a gas supply mass flowmeter are arranged on a main gas supply pipeline between the first end of the tee joint and the high-pressure gas supply source; the second end of the tee joint is connected with a vacuum pump through a pipeline, and a valve is also arranged on the pipeline; the third end of the tee joint is connected with one end of an air supply pipeline, the other end of the air supply pipeline is divided into two branches, each branch is connected with the second sampling point and the third sampling point respectively, and two valves are arranged on the two branches respectively.

The self-generation and self-storage syncline structure basin water soluble gas movement simulation device is preferably as follows: the reservoir simulation system is flexibly connected with the water supply system, the gas-liquid recovery system, the sample collection system and the saturation and vacuum-pumping system through hoses.

Drawings

FIG. 1 is a schematic diagram of unconventional natural gas (coalbed/shale) syncline basin morphology and groundwater runoff;

FIG. 2 is a schematic view of a simulation apparatus for simulating water-soluble gas migration of a self-generating and self-storing syncline-structured basin;

FIG. 3 is a top view of a reservoir simulation system;

FIG. 4 is an enlarged view of the gas-liquid separator;

FIG. 5 is an enlarged front view of the fixing frame;

fig. 6 is an enlarged top view of the fixing frame.

In the figure, 1 is a simulation pipeline; 2 is a simulation pipeline; 3 is a simulation pipeline; 4 is a constant temperature box and a control system; 5 is a vacuum pump; 6 is a valve; 7 is a high-pressure air supply source; 8 is a valve; 9 is a pressure reducing valve; 10 is a tee joint; 11 is a barometer; 12 is a gas supply mass flowmeter; 13 is a constant pressure and constant flow water supply pump; 14 is a water pressure gauge; 15 is a valve; 16(1) and 16(2) are valves; 17 is a water storage tank; 18 is a fixed frame; 18(1) is a horizontal support; 18(2) is a positioning pipe clamp; 19(1) -19 (4) are barometers; 20 is a constant pressure valve; 21 is a temperature sensor; 22 is a hoisting beam; 23 is a fixed frame; 23(1) is a vertical support; 23(2) is a positioning pipe clamp; 23(3) is a circumferential support; 23(4) is a horizontal inner support; 24 is a valve; 25(1) -25 (4) are hoses; 26(1) is a first drain pipe; 26(2) a second drain pipe; 27 is a gas-liquid separator; 28 is a gas pressure balance bottle; 29 is an overflow hole; 30 is a gas collecting pipe; 31 is a valve; 32 is a rubber tube; 33 is a valve; 34(1) -34 (4) are sampling points; 35(1) -35 (4) are valves; 36 is a connector; 36(1) -36 (4) are inlet ports; 36(e) is an output port; 37 is a temperature sensor; 38 is a gas-liquid separator; 38(1) a gas-liquid separation chamber; 38(2) an overflow chamber; 38(3) is a middle clapboard; 39 is a gas recovery container; 40 is a liquid recovery container; 41(1) and 41(2) are valves, and 42 is a scale.

Detailed Description

As shown in FIG. 2, the simulation device for the self-generation and self-storage syncline structure basin water soluble gas movement comprises: the system comprises a reservoir simulation system, a water supply system, a gas-liquid recovery system, a sample collection system, a saturation and vacuumizing system, a hoisting control system, a constant temperature control system and a connecting pipeline system (comprising a connector and a plurality of connecting pipelines connected with the systems).

The thermostatic control system comprises a thermostat 4 and a temperature sensor 21, wherein the thermostat 4 contains liquid such as water, kerosene and the like, and the reservoir simulation device is immersed in the liquid in the thermostat 4. This thermostatic control system's effect is required constant temperature field in the assurance test process, and temperature sensor 21 one end is stretched into and is monitored liquid temperature in thermostated container 4, and the other end includes temperature display device, sets up in the thermostated container outside for show liquid temperature.

The reservoir simulation system comprises 3 hollow simulation pipelines which are respectively a simulation pipeline 1, a simulation pipeline 2 and a simulation pipeline 3. Simulation pipeline 1 is used for simulating the oblique wing that basin supply side place is to, and simulation pipeline 2 is used for simulating the oblique wing that basin drainage side place is to, and simulation pipeline 3 is used for simulating the nearly horizontal segment of basin core portion. The simulation pipeline 1 and the simulation pipeline 2 are in annular winding bending, the length of each section is determined by geometric similarity ratio, the gradient of each section is the same as the section of a prototype, and the change of the gradient of each section is realized by changing the pipeline interval h of the simulation annular pipeline_iOr H_j(i, j are natural numbers). The simulated tube 3 is a horizontal serpentine and its length is determined by the geometric similarity ratio. Determined by equations (1) to (3):

s＝l_i/l_{original i}＝L_i/L_{Original i}＝b/B_{Original source}(1)

sinα_i＝h_i/l_i(2)

sinβ_i＝H_j/L_j(3)

h_i、l_idetermining the section spacing and the section length of the simulation pipeline according to the similarity ratio for the basin supply side respectively;

H_j、L_jrespectively at the drainage side of the basin according to the similarity ratioAnd the section spacing and the section length of the fixed simulation pipeline are determined.

The lower ends of the simulation pipeline 1 and the simulation pipeline 2 are communicated with each other through the simulation pipeline 3, the upper end of the simulation pipeline 1 is connected with a water supply system, the upper end of the simulation pipeline 2 is connected with a gas-liquid recovery system, the upper ends of the simulation pipeline 1 and the simulation pipeline 2 are respectively provided with a fourth sampling point 34(4) and a first sampling point 34(1), and the first sampling point 34(1) and the fourth sampling point 34(4) are respectively connected with a sample collection system. The reservoir simulation system at least needs to set sampling points at the following two places: the third sampling point 34(3) is the joint of the simulation pipeline 1 and the simulation pipeline 3, the second sampling point 34(2) is the joint of the simulation pipeline 2 and the simulation pipeline 3, branch pipelines are respectively provided with a tee joint from the sampling points 34(2) and 34(3), and the branch pipelines are divided into two parts and are respectively connected with the sample collection system and the saturation and vacuum-pumping system. According to research needs, a sampling pipeline can be arranged at the gradient change positions of the simulation pipeline 1 and the simulation pipeline 2, and branch pipelines are led out and are respectively connected with a sample collection system.

As shown in fig. 2, 3, 5 and 6, the hoisting control system includes a hoisting crossbeam 22, two vertical fixing frames 23 (including a vertical support 23 (1)), a positioning pipe clamp 23(2), an annular support 23(3), a horizontal inner support 23(4), a horizontal fixing frame 18 (including a horizontal support 18(1) and a positioning pipe clamp 18(2)), and a hoisting device. The two fixing frames 23 are basically perpendicular to the horizontal fixing frame 18, the fixing frames 23 are respectively provided with annular supports 23(3) at the bottom and the top in a structural form, the upper and lower annular supports 23(3) are respectively provided with two vertically crossed horizontal inner supports 23(4) on the planes, the upper and lower horizontal inner supports are parallel to each other in pairs, the upper and lower horizontal inner supports 23(4) are provided with four vertical supports 23(1) perpendicular to the annular supports 23(3) at the intersections of the upper and lower horizontal inner supports 23(4) and the annular supports 23(3), and the vertical supports 23(1) are provided with positioning pipe clamps 23(2) capable of moving up and down and are respectively used for fixing the simulation pipeline 1 and the simulation pipeline 2 and leading out; the fixing frame 18 is two parallel horizontal supports 18(1), two ends of the horizontal supports 18(1) are fixedly connected with the bottom annular support 23(3) and the horizontal inner support 23(4) of the fixing frame 23, and the horizontal supports 18(1) are provided with positioning pipe clamps 18(2) for fixing the simulation pipeline 3. The horizontal supports 18(1), the horizontal inner supports 23(4) and the vertical supports 23(1) can be supporting rods and hollow supporting columns, the materials are metals such as iron, steel and the like, and the upper annular support 23(3) and the lower annular support can be solid or hollow circular rings; the horizontal support, the vertical support and the circumferential support are connected with each other by adopting a bolt connection mode, a welding mode and the like. The two fixing frames 23 are respectively hung at the two sides below the hoisting beam 22, the fixing frame 18 is basically horizontally arranged at the lower parts of the two fixing frames 23, the two ends of the fixing frame 18 are respectively connected with the two fixing frames 23, the hoisting beam 22, the fixing frames 23 and the fixing frames 18 form a complete fixing device which is hung below the hoisting device, and the reservoir simulation system can be sunk below the liquid level of the heat preservation box 4 and lifted above the liquid level of the heat preservation box 4 by controlling the hoisting device.

The simulation pipeline 1, the simulation pipeline 2 and the simulation pipeline 3 of the reservoir simulation system are filled with samples, the samples are porous gas-containing media, the contained gas can be pure methane gas, coal bed gas, natural gas, shale gas and the like, the gas saturation degree is more than 85%, the media can be coal rock samples, shale, mudstone, active carbon and the like, the non-gas-containing media need pretreatment, the filled samples are vacuumized through a saturation and vacuumizing system, and then the gas supply pressure P is set to perform saturated inflation treatment on the samples, so that the gas saturation degree is more than 85%. After the simulation pipelines are connected, the simulation pipelines are fixed on a fixed frame of a hoisting control system, a hoisting device is placed in a thermostat of a temperature control system, water is supplied by a water supply system, a stable water pressure field and a stable seepage water flow are provided for filling samples in pipelines of a reservoir simulation system, and the constant temperature control system keeps a stable temperature field. The water flow flows through the reservoir simulation system, in the flowing process, gas (gas can be pure methane, coal bed gas, shale gas and the like) contained in the sample is dissolved in water to form water-soluble gas, part of the water-soluble gas flows along with the water, the gas is brought to other places of the pipeline and exchanges with the coal rock sample adsorbed gas through desorption and adsorption, and part of the water-soluble gas is brought out of the reservoir simulation system and enters a gas-liquid recovery system, so that the gas is dissipated, the original gas-containing balance of the coal rock sample is broken, and the water-gas migration rule and the water-soluble gas isotope fractionation rule of the low-permeability self-storage unconventional natural gas (such as the coal bed gas/shale gas) in the solid-liquid-gas three-phase mixed medium of the inclined structure basin can be simulated. The simulation pipeline can be made of high-pressure-resistant, high-temperature-resistant and air-tight materials such as glass tubes, steel tubes, copper tubes and the like, and the interior of the hollow pipeline needs to be passivated.

The water supply system comprises a constant-pressure constant-speed water supply pump 13, a water pressure gauge 14, a water supply valve 15, a constant-pressure valve 20 and a water storage tank 17. The water supply system is connected with the sampling point 34(4) at the upper end of the simulation pipeline 1 of the reservoir simulation system through the hose 25 (4). A water supply valve 15 and a water pressure gauge 14 are arranged between the hose 25(4) and the constant-pressure constant-speed water supply pump 13, a water storage tank 17 supplies water to the constant-pressure constant-speed water supply pump 13 through a pipeline, and a constant-pressure valve 20 is arranged on a connecting pipeline between the inlet port 36(1) and the sampling point 34 (1). The water supply can be selected from basin formation water, deionized water or purified water and the like according to the purpose of a simulation experiment. The stable water supply of the water supply system for the sample of the reservoir simulation system can be realized by adjusting the pressure of the water supply pump 13 and the constant pressure valve 20, a constant water pressure field and stable water flow are provided for the reservoir simulation system, and the test flow is 0.05-1 m³And/min, determining the water supply pressure according to the hydrostatic pressure p of the reservoir in the prototype basin as gamma h (gamma is the water gravity and h is the reservoir burial depth).

The gas-liquid recovery system comprises a gas gauge 19(1), a hose 25(1), a first drainage pipe 26(1), a valve 31, a valve 35(1), a gas-liquid separator 38 (comprising a gas-liquid separation chamber 38(1), an overflow chamber 38(2) and a partition plate 38(3)), a gas recovery container 39, a liquid recovery container 40 and a liquid recovery valve 41 (1). The gas-liquid separator 38 is a container with a vertical middle partition plate, the middle partition plate 38(3) divides the container into two parts from top to bottom, and is divided into a gas-liquid separation chamber 38(1) and an overflow chamber 38(2), except that the bottom edge of the middle partition plate 38(3) is not connected with the inner wall of the bottom of the container, the upper edge and two side edges of the middle partition plate 38(3) are respectively connected with the inner wall of the top of the container, the inner wall of the side part is hermetically connected, and the bottom edge of the middle partition plate 38(3) is close to the bottom of the container, namely, the distance from the bottom of the container is small and is in a slit shape, so that the two. The overflow chamber 38(2) is provided with 1 hole at the top and is connected with a liquid recovery container 40 through a hose. The gas-liquid separation chamber 38(1) is provided with 2 holes at the top, one hole is communicated with a gas recovery container 39 through a gas recovery pipeline, the gas recovery pipeline is provided with a valve 31, the other hole is connected with an outlet port 36(e) of a connector 36 through a first drainage pipe 26(1), the first drainage pipe 26(1) is provided with a liquid recovery valve 41(1), the pipe end of the first drainage pipe 26(1) is inserted into the gas-liquid separation chamber 38(1) and is not more than 1/2 of the container height from the container bottom, and the distance from the container bottom is not less than 2-3 times of the height from the bottom edge of a middle partition plate 38(3) to the container bottom. The first drainage pipe 26(1) is connected with the outlet port 36(e) of the connector 36 through a pipeline, then is connected with the hose 25(1) through the inlet port 36(1) and a connecting pipeline through the connector 36, and is connected with the sampling point 34(1) at the upper end of the simulation pipeline 2 of the reservoir simulation system through the hose 25(1), and the valve 35(1), the pressure gauge 19(1) and the constant pressure valve 20 are sequentially arranged on the connecting pipeline between the inlet port 36(1) and the sampling point 34 (1). The gas-liquid recovery system can collect gas and liquid flowing out of the reservoir simulation system, so that the simulation system forms a complete cycle.

The connector 36 is a pipeline connecting device with a plurality of inlet ports and an outlet port 36(e), the first to fourth inlet ports 36(1) to 36(4) of the connector 36 are respectively connected with the hoses 25(1) to 25(4) through the first to fourth sampling pipelines, the hoses 25(1) to 25(4) are further connected with the first to fourth sampling points 34(1) to 34(4) of the analog pipeline and are used for collecting samples of the sampling points, each pipeline is respectively provided with a valve 35(1) to 35(4), and the connecting pipeline between the port 36(1) and the sampling points 34(1) is simultaneously used as a connecting pipeline of the gas-liquid recovery system. An outlet port 36(e) of the connector 36 is connected with the gas-liquid recovery system and the sample collection system through a first drainage pipe 26(1), wherein the first drainage pipe 26(1) is connected with the gas-liquid recovery system, and a sample recovery valve 41(1) is arranged on a pipeline; the port 36(e) of the connector 36 is also connected to the sample collection system via a second drain tube 26(2) having a sample collection valve 41(2) disposed therein. The ports of the connectors 36 may be expanded to match the number of sampling points of the reservoir simulation system.

The sample collection system comprises a sample collection pipeline and a gas-liquid separation device, the sample collection pipeline is a connecting pipeline between an inlet port 36(1) -36 (4) of the connector 36 and a sampling point 34(1) -34 (4) of the analog pipeline, and each pipeline is provided with a gas pressure gauge 19 and a valve 35. The sample collection pipeline is provided with corresponding sampling pipelines according to the number and the positions of sampling points 34(i) (i is a natural number, 1, 2 and …) arranged in the reservoir simulation system, and is used for collecting gas-liquid mixed samples at different parts of the reservoir simulation system, the pipelines of different sampling points are collected to the connector 36 and connected with the inlet ports 36(i, i is a natural number and the number of the sampling points is the same) of the connector 36, and then the outlet ports 36(e) of the connector 36 are connected with the gas-liquid separation device through the second drainage pipeline 26 (2). The components such as the inlet port 36(i) of the connector 36, the barometer 19(i) on the pipeline, the valve 35(i) and the like are all arranged according to the number and the numbering method of the sampling points 34(i), named according to the name of the component (component name plus (numbering)), and if the corresponding component of the sampling point 34(1) is the inlet port 36(1), the barometer 19(1), the valve 35(1), and the rest are analogized in sequence, and are connected with the corresponding pipeline in sequence.

The gas-liquid separation device comprises a valve 24, a second drainage pipe 26(2), a gas-liquid separator 27, a gas pressure balance bottle 28 (the upper side wall of the gas pressure balance bottle 28 is provided with a liquid overflow hole 29), a gas collecting pipe 30, a rubber pipe 32, a valve 33 and a temperature sensor 37. As shown in fig. 4, the gas-liquid separator 27 is a closed transparent container having open bottom side surfaces and top surfaces, and scale marks 42 are provided on the side surfaces. A gas collecting pipe 30 is arranged in one of the open holes at the top, a gas collecting valve 33 is arranged on the gas collecting pipe 30, and the pipe end of the gas collecting pipe 30 is flush with the top of the container; the other hole is inserted into a second drainage pipe 26(2), and the end of the second drainage pipe 26(2) is deeply inserted into the position below the liquid level in the gas-liquid separator 27 and away from the bottle bottom by no more than 1/3 height of the gas-liquid separator 27; the third aperture mounts a temperature sensor 37 and all aperture walls are sealed from the outer wall of the cannula (or temperature sensor). The gas pressure balancing bottle 28 is a transparent open container with 2 holes on the side surface, one hole is close to the upper part and is an overflow hole 29, and the lower edge of the overflow hole 29 is flush with the top of the gas-liquid separator 27; the other hole is close to the bottom of the container and is positioned at the same height as the opening on the side surface of the bottom of the gas-liquid separator 27, and the other hole is communicated with the opening on the side surface of the bottom of the gas-liquid separator 27 through a rubber pipe 32. The gas pressure balance bottle 28 is open, a water supply pipe is arranged in the gas pressure balance bottle, the other end of the water supply pipe is connected with the water storage tank 17, and a valve 24 is arranged on the water supply pipe. When the gas-liquid separator works, the gas-liquid separator 27 and the gas pressure balance bottle 28 are filled with water, the water level is the position of the lower edge of the overflow hole 29, and no gap is left at the top of the gas-liquid separator 27. The sample collection system has the functions of separating gas from liquid of a gas-liquid mixed sample collected at each sampling point of the reservoir simulation system, preparing the gas sample and providing a test sample for subsequent tests.

The saturation and vacuum-pumping system comprises a vacuum pump 5, a vacuum pump valve 6, a high-pressure air supply source 7, a pressure valve 8, a pressure reducing valve 9, a tee joint 10, a barometer 11, an air supply mass flowmeter 12 and a connecting pipeline thereof. The saturation and vacuum-pumping system is connected with sampling points 34(2) and 34(3) through air supply pipelines, the sampling points 34(2) are the connection positions of the

simulation pipelines

2 and 3, the sampling points 34(3) are the connection positions of the

simulation pipelines

1 and 3, and the air supply valves 16(1) and 16(2) are respectively arranged on the air supply pipelines. The high-pressure gas supply source 7 can respectively provide pure nitrogen gas, pure methane gas or simulation basin reservoir gas, such as coal bed gas, shale gas and pure methane, according to the gas supply requirement. A pressure valve 8, a pressure reducing valve 9, a barometer 11 and an air supply mass flowmeter 12 are arranged on a main air supply pipeline between the first end of the tee joint 10 and the high-pressure air supply source 7; the second end of the tee joint 10 is connected with a vacuum pump 6 through an air pumping pipeline, and a vacuum pump valve 6 is arranged on the air pumping pipeline; the third end of the tee joint 10 is connected with one end of an air supply pipeline, the other end of the air supply pipeline is divided into two air supply branches, each branch is respectively connected with a sampling point 34(2) and a sampling point 34(3), and a first air supply valve 16(1) and a second air supply valve 16(2) are respectively arranged on the first air supply branch and the second air supply branch. The saturation and vacuum-pumping system can vacuumize a gas-free sample filled in the reservoir simulation system, set the gas supply pressure P to perform saturation aeration treatment on the sample, prepare a high-pressure gas-containing sample, simulate the self-generation self-gas-storage reservoir and restore the original uniform gas-containing reservoir, wherein the gas saturation of the sample reaches over 85 percent.

The reservoir simulation system is flexibly connected with the water supply system, the gas-liquid recovery system, the sample collection system and the saturation and vacuum-pumping system through the hoses 25(i, i is a natural number, i is 1, 2, 3 and 4), so that the reservoir simulation system can be conveniently lifted and lowered, the installation of a sample in a simulation pipeline before an experiment is facilitated, the simulation temperature is controlled in the experiment, and the sample in the simulation pipeline is taken out after the experiment. The hose 25(i) is a high-temperature and high-pressure resistant elastic hose, and the material can be stainless steel or rubber.

The following description is given by using the first and second examples to illustrate the experimental method for the influence of water-soluble gas on isotope fractionation of unconventional natural gas (such as coal bed gas) in a reservoir by using the simulation device for water-soluble gas migration from a self-generated and self-stored syncline basin of the invention:

the first embodiment is as follows:

as shown in fig. 2, the simulation device for migration of water-soluble gas in a self-generation and self-storage syncline-structured basin comprises a reservoir simulation system, a water supply system, a gas-liquid recovery system, a sample collection system, a saturation and vacuum-pumping system, a hoisting control system, a constant temperature control system and related connecting pipelines. The simulation experiment method comprises the steps of preparation before experiment, simulation experiment and sampling analysis.

First, preparation before experiment

1) The method comprises the steps of constructing a basin prototype section according to gas storage syncline, dividing the section into sections with gas self-generation self-storage reservoir, determining section types, determining the section types according to the prototype syncline basin, determining the section of the basin reservoir, extracting main gradient types, lengths and combination relations representing the reservoir section characteristics according to the reservoir section gradient characteristics, and dividing the gradient types according to the following gradient classification principle, wherein a near horizontal section (α is less than or equal to 5 degrees), a slow inclined section (5 degrees is less than or equal to α is less than or equal to 15 degrees), an inclined section (15 degrees is less than or equal to α is less than or equal to 35 degrees), and a fast inclined section (α is more than 35 degrees), two syncline wings are generally divided into no more than 3 main gradient types, the main combination relations of the section gradient types are determined, different combination relations such as slow inclination-fast inclination or slow inclination-fast inclination-inclination, and the slopes of different sections are the same, the lengths of the minor sections do not influence the combination relations of the section types, and the main section length of.

2) And calculating the length of the section of the simulation pipeline, the section interval of the simulation pipeline and the combination relation. Determining a simulation geometric similarity ratio, determining the total lengths and the segment lengths of a simulation pipeline 1, a simulation pipeline 2 and a simulation pipeline 3 corresponding to a reservoir simulation system according to the simulation geometric similarity ratio, determining the segment slopes of the simulation pipeline 1 and the simulation pipeline 2, dividing and counting according to a slope classification principle, determining the median of each segment slope statistic of a prototype basin, and determining the length of the simulation pipeline and the segment interval of the simulation pipeline according to formulas (1) to (3):

s＝l_i/l_{original i}＝L_i/L_{Original i}＝b/B_{Original source}(1)

sinα_i＝h_i/l_i(2)

sinβ_i＝H_j/L_j(3)

H_j、L_jthe simulation pipeline section spacing and the section length determined by the basin drainage side according to the similarity ratio are represented.

i and j are natural numbers which respectively represent the number of sections of the basin supply side model pipeline and the basin drainage side model pipeline.

3) And manufacturing a section simulation pipeline and connecting the system pipeline. After the simulation pipeline 1, the simulation pipeline 2 and the simulation pipeline 3 with corresponding lengths and gradients are manufactured, the simulation pipelines are connected according to the combination relationship of section types and are respectively fixed on two vertical fixing frames 23 and one horizontal fixing frame 18, wherein the simulation pipeline 1 and the simulation pipeline 2 are respectively fixed on the two vertical fixing frames 23, the positions of pipe clamps 23(2) are adjusted and fixed section by section according to the section spacing, the simulation pipeline 3 is fixed on the pipe clamps 18(2) on the horizontal fixing frame 18, the horizontal fixing frame 18 is respectively connected with the bottoms of the two vertical fixing frames 23, the lifting cross beam 22 is hung on a lifting device after the two vertical fixing frames 23 and the lifting cross beam 22 are combined, and then the reservoir simulation system is sequentially connected with other systems.

The reservoir simulation system has the following connection mode: the upper end of the simulation pipeline 1 is connected with a hose 25(4) and then is connected with a water supply system, and the upper end of the pipeline is simultaneously used as a sampling point 34(4) and is connected with an inlet 36(4) through a sampling pipeline; the upper end of the simulation pipeline 2 is connected with a hose 25(1) and then is communicated with a gas-liquid recovery system, and the upper end of the simulation pipeline is also used as a sampling point 34(1) and is connected with an inlet 36(1) through a sampling pipeline; a branch pipe is led out from the connection part of the simulation pipeline 1 and the simulation pipeline 3 and is used as a sampling point 34(3), and the branch pipeline is divided into two parts and is respectively connected with an inlet port 36(3) and a saturation and vacuum-pumping system; the branch pipe is led out from the connection part of the simulation pipeline 2 and the simulation pipeline 3 and is used as a sampling point 34(2), and the branch pipeline is divided into two parts and is respectively connected with an inlet port 36(2) and a saturation and vacuum-pumping system. Sampling points 34(1) to 34(4) are converged and connected to inlet ports 36(1) to 34(4) of a connector 36 through sampling pipelines, and then connected with a gas-liquid recovery system and a sample collection system through an outlet port 36(e) of the connector 36.

After the reservoir simulation system, the water supply system, the gas-liquid recovery system, the sample collection system and the saturation and vacuum-pumping system are connected, the hoisting control system places the simulation pipeline of the reservoir simulation system below the liquid level of the thermostat 4 of the thermostatic control system, and simultaneously, the temperature of the thermostatic control system is set, and the temperature of the liquid in the thermostat is heated to the set temperature. All valves of the simulation apparatus were closed before the start of the test.

4) And (5) debugging a sample collection system and a gas-liquid recovery system. And opening the valve 24, filling water into the containers of the gas-liquid separator 27 and the gas pressure balance bottle 28 of the sample collection system, wherein the water level is the position of the lower edge of the overflow hole 29, no gap is left at the top of the gas-liquid separator 27 after the water is filled, and closing the valve 24. The gas-liquid separator 38(1) of the gas-liquid recovery system is filled with water in advance, or the water level is higher than or equal to the water level at least to submerge the end of the first drain pipe 26 (1).

5) And (6) checking the air tightness. Firstly, selecting nitrogen from a high-pressure gas supply source 7, opening a gas supply valve 8, adjusting a pressure reducing valve 9, setting the pressure in a simulation pipeline of a reservoir simulation system as a test pressure W, wherein the test pressure W is (1.5-2.0) p, the p is the hydrostatic pressure of a reservoir in a prototype basin, and the p is gamma h (gamma is the gravity of water, and h is the buried depth of the reservoir), and checking the tightness of the pipeline of the whole device.

6) And (5) simulating pipeline sample loading. A pipeline system with good sealing performance is characterized in that a lifting device lifts a simulation pipeline 1-a simulation pipeline 3 to a position above the liquid level of a thermostat 4, a prepared fresh and dry coal rock sample is selected, the coal rock sample needs to be fully desorbed and does not contain residual gas, the particle size of the coal rock sample is 1/5-1/10 of the inner diameter of the simulation pipeline, the broken coal rock sample is filled into the simulation pipeline 1, the simulation pipeline 2 and the simulation pipeline 3 in a segmented mode, after the coal sample is filled, a simulation pipeline connector and a connecting pipeline are connected again to guarantee sealing integrity, then the lifting device enables the simulation pipeline 1-the simulation pipeline 3 to be completely immersed below the liquid level of the thermostat 4, and an experiment starts.

Second, simulation experiment

The simulation experiment was performed as follows:

1) before the system starts to test, all valves of the system are in a closed state;

2) opening a vacuum pump valve 6, an air supply valve 16(1), a gas supply valve 16(2) and a vacuum pump 5, continuously vacuumizing a reservoir simulation system for more than 6-8 h, then closing the vacuum pump 5, the valve 6 and the air supply valve 16(1), the gas supply valve 16(2), standing for more than 3-5 h, checking readings of barometers 19(1) -19 (4), checking whether the readings of all the barometers are stable and unstable, indicating that residual gas exists in a sample filled in the reservoir simulation system, continuously vacuumizing, re-checking, repeating the steps until the readings of the barometers are stable, and entering the next step of the experiment;

3) the method comprises the steps of replacing a high-pressure gas supply source 7 with a high-pressure gas cylinder to be detected, such as coal bed gas, opening a valve 8 on a main gas supply pipeline and gas supply valves 16(1) and 16(2) on a gas supply branch, adjusting a pressure reducing valve 9, setting gas supply pressure P as (1.0-1.2) P, and determining the gas supply pressure P according to the hydrostatic pressure P of a prototype basin reservoir as gamma h (gamma is the gravity of water, and h is the reservoir burial depth). Filling coalbed methane into a simulation pipe of a reservoir simulation system, wherein the injection time lasts for more than 24h, closing a valve 8, an air supply valve 16(1) and a gas supply valve 16(2), standing for more than 1 h, continuously observing a gas pressure gauge 19(i) (19(1) - (19 (4)) if the reading is stable, indicating that the coalbed methane adsorbed and desorbed by a filling sample in the simulation pipe reaches balance, and entering the next step; if any of the barometer 19(i) readings are not stable, the valve 8, the gas supply valves 16(1) and 16(2) are reopened and the simulation tubes of the reservoir simulation system continue to be charged with coalbed methane. This is repeated until all barometer 19(i) readings have stabilized, valve 8, supply valves 16(1) and 16(2) are closed, and the experiment proceeds to the next step. And simultaneously, the indication values of the gas mass flowmeter 12 and the gas pressure meter 19(i) are recorded, and the accumulated filling mass of the gas to be measured of the system and the balanced gas supply pressure are determined.

4) The water supply valve 15 is opened, the constant pressure valve 20 is adjusted, the constant speed and constant pressure pump 13 is opened in sequence, water is stably injected into the simulation pipeline 1, the simulation pipeline 2 and the simulation pipeline 3 of the reservoir simulation system at a level slightly higher than the hydrostatic pressure p of the reservoir of the prototype basin, and the test flow is 0.1-0.5 m³And/min, when the water flow reaches the valve 35(1), sequentially opening the valve 35(1), the valve 41(1) and the valve 31, leading the liquid in the pipe to reach the gas-liquid separator 38, realizing gas-liquid separation in the gas-liquid separator 38(1), discharging the gas through the valve 31, collecting the gas by the recovery container 39, leading the liquid to flow through the overflow chamber 38(2), collecting the liquid by the liquid recovery container 40, and discharging or disposing according to the regulation.

5) And (6) collecting a gas sample. According to the experimental requirement, the sampling time interval is determined, and then the gas samples at the positions 34(1) -34 (4) are collected in sequence. When the sample at the sampling point 34(1) is collected, the valve 41(1) is closed, the valve 41(2) is opened, the gas-liquid separator 27 is kept still for a certain time, the side scale 42 of the gas-liquid separator 27 is observed, the time for generating a certain volume of gas is recorded, the gas volume is at least more than 10ml, the reading of the temperature sensor 37 is recorded, the valve 35(1) and the valve 41(2) are closed, the valve 24 is opened, water is supplied to the gas pressure balancing bottle 28 through a water supply pipe, the valve 33 is opened simultaneously, a vacuum gas collection bottle or a sampling bag is adopted to collect the gas sample, the valve 33 is closed after the sampling is. And (3) closing the valve 24 when the gas-liquid separator 27 and the gas pressure balance bottle 28 are refilled with liquid and no gap is left at the top after the gas-liquid separator 27 is filled with liquid, and finishing sampling at the sampling point 34 (1).

Collecting samples at a sampling point 34(2), opening a valve 35(2) and a valve 41(1), discharging liquid flowing out of the sampling point 34(2) for a period of time to discharge the residual sample at the last time, closing the valve 41(1), opening the valve 41(2), standing for a certain time, observing the side scale 42 of the gas-liquid separator 27, recording the time for generating a certain volume of gas, the gas volume being at least more than 10ml, recording the reading of the temperature sensor 37, closing the valve 35(2) and the valve 41(2), opening the valve 24, supplying water into the gas pressure balancing bottle 28 through a water supply pipe, simultaneously opening the valve 33, collecting the gas samples by using a vacuum gas collection bottle or a sampling bag, closing the valve 33 after sampling, numbering the gas samples, and when the gas-liquid separator 27 and the gas pressure balancing bottle 28 are refilled with liquid and no gap is left at the top after the gas-liquid separator 27 is filled with liquid, valve 24 is closed and sampling point 34(2) is complete.

Sampling processes and methods at sampling points 34(3) and 34(4) are the same as the sampling points 34(2), pipeline valves 35(3) or valves 35(4) at the sampling points are opened in sequence, sampling is performed in sequence, gas samples are numbered, and after sampling is completed, the valves 35(1) and 41(1) are opened again, so that liquid flowing through the reservoir simulation system flows to the gas-liquid recovery system again.

6) And (5) repeating the step 5) to sample until the next sampling time, and circulating the steps till the test is finished.

7) And calculating the gas solubility. The gas solubility is calculated as follows:

C_m＝n/(V_m×ρ)(1)

in the formula: c_mGas solubility at a certain temperature and under 1 atmosphere pressure, mol/kg;

n is the mole number and mol of the collected gas sample;

V_mthe volume of liquid displaced for the gas sample, in this experiment, is equal to the volume of gas sample collected, m³；

Rho is the density of the liquid, kg/m³。

8) Changing experimental conditions, such as physical parameters (including coal quality, particle size, porosity and the like), a gas supply medium (pure methane gas), a liquid medium (taking ionized water and pure water), water supply pressure, water supply flow, temperature and the like of the reservoir sample, and performing the steps 1-7) again.

Third, sample testing, data analysis

The method comprises the steps of carrying out component analysis and stable carbon isotope and hydrogen isotope tests on collected coal bed gas samples, predicting the influence of underground water flow on the gas content and distribution of reservoir gas in different sections according to the sample components and stable carbon isotope and hydrogen isotope change rules at different sampling intervals, providing an experimental basis for research of coal bed gas causes, reserves and occurrence states, and providing theoretical support for the effective development of unconventional natural gas.

The second embodiment:

first, preparation before experiment and simulation experiment

Preparations 1) to 5) before the experiment were the same as in example one. The difference lies in that

1) In the preparation process before the experiment, the second end of the tee joint 10 in the saturation and vacuum-pumping system in the step 3) is not required to be connected with an air pumping pipeline and a vacuum pump 6, and is only connected with a pipeline where the high-pressure air supply source 7 is located; and 6), filling samples into the simulation pipelines 1-3 after the pipelines are connected, wherein the samples are original gas-containing coal rock samples which are fresh and do not desorb coal bed gas.

In the simulation experiment, the samples filled in the simulation pipelines 1-3 are original gas-containing coal rock samples, and the step 2) and the step 3) are omitted. Execution is started from step 4). The method comprises the steps of quickly crushing a newly collected original gas-containing coal rock sample, directly loading the crushed sample into a simulation pipeline of a reservoir simulation system, connecting an experimental device, setting the pressure of a constant pressure valve 20, opening a water inlet valve 15, and supplying water to the simulation pipeline according to the hydrostatic pressure p of a reservoir in a basin (gamma is the gravity of water, and h is the reservoir burial depth). Then, the experiment and the sampling were performed according to steps 4) to 6) of the simulation experiment in example one.

Second, sample testing and data analysis

The simulation experiment method for the migration of the water-soluble gas from the self-generation self-storage to the inclined structure basin realizes the simulation of the basin geological condition of the self-generation self-storage structure, provides an experiment of the influence of underground water on the size and the distribution of the gas content of original samples of the coal bed gas in different sections of the reservoir, provides an experiment foundation for the research of the formation, the accumulation and the occurrence states of the coal bed gas by testing the change rule and the change rule of the gas content of stable carbon isotopes and hydrogen isotopes in different sections and establishing the change relationship between the gas content and the stable gas isotopes and the simulation acquisition of data, and adopts a simple device structure, small floor area and accurate and simple simulation experiment method, thereby providing basic theoretical support for the development of the coal bed gas/shale gas.

Claims

1. A simulation experiment method for water-soluble gas migration uses a simulation device for water-soluble gas migration of a self-generated and self-stored syncline-structured basin to perform an experiment,

the self-generation and self-storage syncline structure basin water soluble gas movement simulation device comprises: reservoir simulation system, water supply system, gas-liquid recovery system, sample collection system, saturation and evacuation system, lift by crane control system and constant temperature control system, wherein: reservoir bed

The simulation system comprises a simulation pipeline, 4 sampling points are arranged on the simulation pipeline, the reservoir simulation system is placed in the constant temperature control system, and the constant temperature control system provides a preset working temperature for the reservoir simulation system; the water supply system is connected with the reservoir simulation system through a pipeline and supplies water to the reservoir simulation system; the gas-liquid recovery system and the sample collection system are both connected with the reservoir simulation system through pipelines to collect gas and liquid flowing out of the reservoir simulation system; the saturation and vacuum-pumping system is connected with the reservoir simulation system through a pipeline, and is used for vacuumizing a sample filled in the reservoir simulation system and carrying out high-pressure gas saturation treatment;

the hoisting control system is used for hoisting the reservoir simulation system so as to put the reservoir simulation system into the constant temperature control system or hoist the reservoir simulation system out of the constant temperature control system;

the reservoir simulation system comprises a first simulation pipeline, a second simulation pipeline and a third simulation pipeline, the lower ends of the first simulation pipeline and the second simulation pipeline are mutually communicated through the third simulation pipeline, the upper ends of the first simulation pipeline and the second simulation pipeline are respectively provided with a fourth sampling point and a first sampling point, the fourth sampling point and the first sampling point are respectively connected with the sample collection system and the gas-liquid recovery system through connecting pipelines, and the fourth sampling point is connected with the water supply system through connecting pipelines; respectively arranging a third sampling point and a second sampling point at the joint of the first simulation pipeline and the third simulation pipeline and the joint of the second simulation pipeline and the third simulation pipeline, wherein the third sampling point and the second sampling point are respectively connected with the sample acquisition system and the gas-liquid recovery system through connecting pipelines and are connected with the saturation and vacuumizing system;

the water supply pump is connected with the reservoir simulation system through a water supply pipeline, a water supply valve and a water pressure meter are arranged between the water supply pipeline and the water supply pump, a constant pressure valve is arranged on a connecting pipeline between the connector and the first sampling point and is matched with the water supply pump to set the pressure of the reservoir simulation system, and the water storage tank provides water for the water supply pump;

the gas-liquid recovery system comprises a gas-pressure meter, a first drainage pipe, a valve, a first gas-liquid separator, a gas recovery container and a liquid recovery container; the first gas-liquid separator is a container with a vertical middle clapboard, the middle clapboard vertically divides the container into two parts from top to bottom and divides the container into a gas-liquid separation chamber and an overflow chamber, the middle clapboard is not connected with the inner wall of the bottom of the container except the bottom edge, the upper edge and two side edges of the middle clapboard are respectively connected with the inner wall of the top of the container in a sealing way, the bottom edge of the middle clapboard is very close to the bottom of the container, namely, the distance from the bottom of the container is very small and is in a slit shape, the gas-liquid separation chamber and the overflow chamber are communicated at the bottom, the top of the overflow chamber is provided with a hole which is connected with the liquid recovery container through a pipeline, the top of the gas-liquid separation chamber is provided with two holes, one hole is communicated with the gas recovery container through a gas recovery pipeline, the pipeline is provided with a valve, the other hole is connected with an outlet port of a connector through a first drainage pipe, the first drainage pipe is provided with a, and the distance from the bottom of the gas-liquid separation chamber to the bottom of the middle partition plate is not less than 2-3 times of the distance from the bottom of the gas-liquid separation chamber to the bottom of the gas-liquid separation chamber;

the simulation device for the self-generation and self-storage syncline structure basin water-soluble gas movement further comprises a connector; wherein: the connector is a pipeline connecting device with a plurality of inlet ports and an outlet port, the four inlet ports of the connector are respectively connected with first sampling points to fourth sampling points of a simulation pipeline of a reservoir simulation system through first sampling pipelines to fourth sampling pipelines, and each sampling pipeline is respectively provided with a valve; the outlet port of the connector is connected with a gas-liquid recovery system through a first drainage pipe, and a valve is arranged on the pipeline of the first drainage pipe; the outlet port of the connector is also connected with a sample collecting system through a second drainage pipe, and a valve is arranged on the pipeline of the second drainage pipe;

the sample collection system comprises a sample collection pipeline and a gas-liquid separation device, wherein:

the sampling device comprises a sampling pipeline, a gas pressure meter, a valve, a connector, a sampling pipeline, a gas-liquid separation device and a gas-liquid separation device, wherein the sampling pipeline is a connecting pipeline between an inlet port of the connector and sampling points of a simulation pipeline, each pipeline is provided with the gas pressure meter and the valve, the sampling pipeline is correspondingly configured according to the number and the position of the sampling points set by a reservoir simulation system, the sampling pipeline is used for collecting gas-liquid mixed samples at different parts of the reservoir simulation system, the collecting pipelines at different sampling points are converged to the connector and are respectively connected with the corresponding inlet ports of the connector, and then the outlet ports of the connector are connected;

the gas-liquid separation device comprises a valve, a second gas-liquid separator, a gas pressure balance bottle, a gas collecting pipe and a temperature sensor; the second gas-liquid separator is a closed transparent container with an opening at the side surface of the lower part and an opening at the top, scales are marked on the side surface, a gas collecting pipe is arranged in one hole in the opening at the top, a gas collecting valve is arranged on the gas collecting pipe, and the pipe end of the gas collecting pipe is flush with the top of the container; a second drainage pipe is inserted into the other hole, a valve is arranged on the second drainage pipe, and the pipe end of the second drainage pipe is deeply inserted below the liquid level in the second gas-liquid separator and is not more than 1/3 from the bottom; the third hole is provided with a temperature sensor; the gas pressure balance bottle is a transparent open container with 2 holes in the side surface, one hole is close to the upper part and is an overflow hole, and the lower edge of the overflow hole is flush with the top of the second gas-liquid separator; the other hole is close to the bottom of the container, the height of the hole is the same as that of the hole on the side surface of the bottom of the second gas-liquid separator, the other hole is communicated with the hole on the side surface of the bottom of the gas separator through a pipeline, a water supply pipe is arranged in the gas pressure balance bottle, the other end of the water supply pipe is connected with a water storage tank, and a valve is arranged on the water supply pipe;

the saturation and vacuum-pumping system comprises a vacuum pump, a vacuum pump valve, a high-pressure gas supply source, a pressure valve, a pressure reducing valve, a barometer, a gas mass flowmeter and a tee joint; wherein: a pressure valve, a pressure reducing valve, a barometer and a gas mass flowmeter are arranged on a main gas supply pipeline between the first end of the tee joint and the high-pressure gas supply source; the second end of the tee joint is connected with a vacuum pump through a pipeline, and a valve is also arranged on the pipeline; the third end of the tee joint is connected with one end of an air supply pipeline, the other end of the air supply pipeline is divided into two branches, namely a first air supply branch and a second air supply branch, the first air supply branch is connected with the second sampling point, the second air supply branch is connected with the third sampling point, and two branches are respectively provided with a valve;

the method is characterized by comprising a simulation experiment step, wherein the simulation experiment step comprises the following steps:

3) opening a pressure valve of the high-pressure gas cylinder to be detected, adjusting a pressure reducing valve, setting gas supply pressure P, continuously supplying gas until the readings of all barometers are stable, closing the pressure valve, and entering the next step; simultaneously recording the numerical values of the gas mass flowmeter and the barometer;

4) opening a water supply valve, adjusting a constant pressure valve, opening a water supply pump, stably injecting water into a simulation pipeline of the reservoir simulation system by the water supply pump at a pressure slightly higher than the hydrostatic pressure p of the reservoir in the prototype basin, enabling liquid in a first drainage pipe to reach a first gas-liquid separator, realizing gas-liquid separation in the first gas-liquid separator, discharging gas through a valve on a gas recovery pipeline, collecting the gas by a recovery container, and collecting the liquid by a liquid recovery container after the liquid flows through an overflow chamber;

6) repeating the step 5) to sample at the next sampling time, and circulating the steps until the sampling is finished;

s＝l_i/l_{original i}＝L_i/L_{Original i}＝b/B_{Original source}(1)

sinα_i＝h_i/l_i(2)

sinβ_i＝H_j/L_j(3)

H_j、L_jfor representing the spacing and division of simulated pipes determined by the drainage sides of the basin in a similar ratioA segment length;

4) opening a valve on a water supply pipe, filling water into a second gas-liquid separator of the sample collection system and a container of a gas pressure balance bottle, leaving no gap at the top after the second gas-liquid separator is filled with water, and closing the valve of the water supply pipe; the first gas-liquid separator of the gas-liquid recovery system is filled with water in advance, or the water filling height at least submerges the pipe end of the first drainage pipe;

2. The experimental method according to claim 1, characterized in that: the step of simulating the experiment further comprises step 7): changing the experimental conditions, including one or the combination of the physical parameters of the reservoir sample, the gas supply medium, the liquid medium, the water supply pressure, the water supply flow and the temperature.

3. The experimental method according to claim 1, characterized in that: the step 2) in the simulation experiment step is specifically as follows:

4. The experimental method according to claim 1, characterized in that: the step 3) in the simulation experiment step is specifically as follows:

switching a high-pressure air supply source into a high-pressure air bottle to be tested, opening a pressure valve on a main air supply pipeline, opening air supply valves on a first air supply branch and a second air supply branch, adjusting a pressure reducing valve, and setting air supply pressure; filling hydrocarbon test gas into a simulation pipeline of the reservoir simulation system, continuously injecting for a preset time, closing a pressure valve on a main gas supply pipeline, standing for a period of time, continuously observing readings of all barometers, and entering the next step if the readings are stable; and if the reading of any barometer is unstable, re-opening the pressure valve on the main gas supply pipeline, continuously filling test gas into the simulation pipeline of the reservoir simulation system, repeating the steps until the reading of all barometers is stable, closing the pressure valve on the main gas supply pipeline, entering the next step of the experiment, simultaneously recording the gas mass flowmeter and all the gas pressure representation values, and determining the accumulated filling quality of the gas to be measured of the system and the balanced gas supply pressure.

5. The experimental method as claimed in claim 1, wherein said simulation device for simulating the movement of water soluble gas from self-generating reservoir to syncline structure basin comprises: reservoir simulation system, water supply system, gas-liquid recovery system, sample collection system, saturation and evacuation system, lift by crane control system and constant temperature control system, wherein:

6. A simulation experiment method for water-soluble gas migration uses a simulation device for water-soluble gas migration of a self-generated and self-stored syncline-structured basin to perform an experiment,

the self-generation and self-storage syncline structure basin water soluble gas movement simulation device comprises: reservoir simulation system, water supply system, gas-liquid recovery system, sample collection system, saturation and evacuation system, lift by crane control system and constant temperature control system, wherein: the reservoir simulation system comprises a simulation pipeline, wherein 4 sampling points are arranged on the simulation pipeline, the reservoir simulation system is placed in a constant temperature control system, and the constant temperature control system provides a preset working temperature for the reservoir simulation system; the water supply system is connected with the reservoir simulation system through a pipeline and supplies water to the reservoir simulation system; the gas-liquid recovery system and the sample collection system are both connected with the reservoir simulation system through pipelines to collect gas and liquid flowing out of the reservoir simulation system; the saturation and vacuum-pumping system is connected with the reservoir simulation system through a pipeline, and is used for vacuumizing a sample filled in the reservoir simulation system and carrying out high-pressure gas saturation treatment; the hoisting control system is used for hoisting the reservoir simulation system so as to put the reservoir simulation system into the constant temperature control system or hoist the reservoir simulation system out of the constant temperature control system;

the samples filled in the first simulation pipeline, the second simulation pipeline and the third simulation pipeline are original gas-containing coal rock samples without fresh desorption coal bed gas;

the method is characterized in that the experimental method simulates the experimental steps, and the simulated experimental steps comprise:

2) opening a water supply valve, adjusting a constant pressure valve, opening a water supply pump, stably injecting water into a simulation pipeline of the reservoir simulation system by the water supply pump at a pressure slightly higher than the hydrostatic pressure p of the reservoir in the prototype basin, enabling liquid in a first drainage pipe to reach a first gas-liquid separator, realizing gas-liquid separation in the first gas-liquid separator, discharging gas through a valve on a gas recovery pipeline, collecting the gas by a recovery container, and collecting the liquid by a liquid recovery container after the liquid flows through an overflow chamber;

4) repeating the step 3) to sample at the next sampling time, and circulating the steps until the sampling is finished;

the step 3) in the simulation experiment step includes: determining sampling time interval according to test requirements, and then sequentially collecting gas samples at a first sampling point to a fourth sampling point, wherein,

when a sample at a first sampling point is collected, closing a liquid recovery valve, opening a valve on a second drainage pipeline, standing for a certain time, observing the side scale of a second gas-liquid separator, recording the time for generating a certain volume of gas, recording the reading of a temperature sensor, opening a gas collection valve, collecting a gas sample, numbering the gas sample, closing the valve on the first sampling pipeline and the valve on the second drainage pipeline, opening a valve on a water supply pipe, refilling the second gas-liquid separator and a gas pressure balance bottle with liquid, enabling the second gas-liquid separator to be full of liquid and then enabling no gap to be left at the top, closing the valve of the water supply pipe, and finishing sampling at the first sampling point;

when a sample at a second sampling point is collected, a valve on a second sampling pipeline and a valve on a first drainage pipeline are opened, liquid flowing out from the second sampling point is discharged for a period of time, the valve on the first drainage pipeline is closed, the valve on the second drainage pipeline is opened, standing is carried out for a certain time, the side scale of a second gas-liquid separator is observed, the time for generating a certain volume of gas is recorded, the reading of a temperature sensor is recorded, a gas collecting valve is opened, a gas sample is collected, the gas sample is numbered, the valve on the second sampling pipeline and the valve on a second drainage pipe are closed, the valve on a water supply pipe is opened, the second gas-liquid separator and a gas pressure balance bottle are refilled with liquid, no gap is left at the top after the second gas-liquid separator is filled with the liquid, the valve of the water supply pipe is closed, and the;

when a sample at a third sampling point is collected, a valve on a third sampling pipeline and a valve on a first drainage pipeline are opened, liquid flowing out from the third sampling point is discharged for a period of time, the valve on the first drainage pipeline is closed, the valve on a second drainage pipeline is opened, standing is carried out for a certain time, the side scale of a second gas-liquid separator is observed, the time for generating a certain volume of gas is recorded, the reading of a temperature sensor is recorded, a gas collecting valve is opened, a gas sample is collected, the gas sample is numbered, the valve on the third sampling pipeline and the valve on a second drainage pipe are closed, the valve on a water supply pipe is opened, the second gas-liquid separator and a gas pressure balance bottle are refilled with liquid, no gap is left at the top after the second gas-liquid separator is filled with the liquid, the valve of the water supply pipe is closed, and the;

when the sample at the fourth sampling point is collected, a valve on a fourth sampling pipeline and a valve on a first drainage pipeline are opened, liquid flowing out from the fourth sampling point is discharged for a period of time, the valve on the first drainage pipeline is closed, the valve on a second drainage pipeline is opened, the valve is kept still for a certain time, the side scale of a second gas-liquid separator is observed, the time for generating a certain volume of gas is recorded, the reading of a temperature sensor is recorded, a gas collecting valve is opened, a gas sample is collected, the gas sample is numbered, the valve on the fourth sampling pipeline and the valve on a second drainage pipe are closed, the valve on a water supply pipe is opened, the second gas-liquid separator and a gas pressure balance bottle are refilled with liquid, no gap is left at the top after the gas-liquid separator is filled with the liquid, the valve of the water supply pipe is closed.