Simulation experiment device for collaborative exploitation of tight gas and deep coal bed gas

Abstract

The invention provides a tight gas and deep coal bed gas collaborative exploitation simulation experiment device. The tight gas and deep coal bed gas collaborative exploitation simulation experiment device is composed of a shaft simulation device, a reservoir simulation device, a gas-liquid two-phase flow supply device and a control system. The casing pipe is provided with a plurality of transparent converging sections, and the oil pipe can be downwards inserted to different layers. And the gas-liquid two-phase flow supply device is provided with a plurality of groups of independent gas-liquid conveying manifolds which are respectively connected with each convergence section of the sleeve through the reservoir simulation device, so that the independent regulation and control of seepage parameters and production pressure difference of each layer are realized. The control system integrates pressure and flow acquisition and image recording functions, monitors and analyzes data in real time, is used for simulating an interlayer coupling relationship, a mutual interference mechanism and dynamic productivity response during multi-layer commingling production, and provides an experimental basis for collaborative production layer strategy optimization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas exploitation, and particularly relates to a simulation experiment device for cooperative exploitation of tight gas and deep coalbed gas. BACKGROUND

[0002] In recent years, the unconventional natural gas exploration and development in China has developed rapidly. Coalbed gas resources, as an important field for increasing reserves and production, have the characteristics of wide distribution, large reserves and deep burial, and are mainly distributed in North China, Ordos, Junggar and Northeast China. However, the coalbed gas reservoir has complex geological conditions, poor reservoir properties and high exploitation difficulty, and most gas wells have the problem of low single-resource exploitation benefit. Especially in the vertically superimposed reservoirs of tight gas and deep coalbed gas, the problems of low resource utilization rate and poor economic benefit are prominent, although there is a geological basis for cooperative exploitation in the same well, which can save drilling cost, improve single-well production and prolong the development period. However, there are significant differences in pressure, gas-liquid ratio and fluid properties between the superimposed reservoirs, and the different gas pressure control principles easily cause interlayer interference, which affects the productivity.

[0003] At present, there are several experimental devices dedicated to simulating the commingling process of multi-layer gas reservoirs, but these existing technologies mainly focus on the simulation of a single link--either only for reservoir production characteristics or only for the study of wellbore multiphase flow state. Although some devices attempt to connect the reservoir and the wellbore, they still lack systematic and adjustable experimental simulation capabilities in terms of wellbore-reservoir dynamic coupling, multi-layer pressure linkage response and flow interference mechanism, and it is difficult to truly restore the dynamic interaction process in the cooperative exploitation. Especially, there are obvious deficiencies in aspects such as deep adjustment under the oil pipe, production pressure difference control and quantitative evaluation of interlayer interference. SUMMARY

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application provides a simulation experiment device for cooperative exploitation of tight gas and deep coalbed gas, which aims to solve the problem that the experimental device in the related art cannot truly restore the dynamic interaction process in the cooperative exploitation of tight gas and deep coalbed gas.

[0005] The present application provides a simulation experiment device for cooperative exploitation of tight gas and deep coalbed gas, which comprises: a wellbore simulation device comprising a casing and a tubing, at least two inflow sections are arranged on the casing, and at least the inflow sections of the casing are made of transparent material, and the tubing is used to penetrate from the top of the casing to different inflow sections; a reservoir simulation device, which is used to fill reservoir simulation particles to simulate different permeability reservoir characteristics; The gas-liquid two-phase flow supply device comprises a gas supply assembly, a liquid supply assembly and at least two groups of gas-liquid delivery manifolds, each group of the gas-liquid delivery manifolds comprises a gas delivery pipeline, a liquid delivery pipeline and a gas-liquid mixer, an upstream end of the gas delivery pipeline is connected with the gas supply assembly, a downstream end of the gas delivery pipeline is connected with the gas-liquid mixer, a gas flow meter is arranged on the gas delivery pipeline, an upstream end of the liquid delivery pipeline is connected with the liquid supply assembly, a downstream end of the liquid delivery pipeline is connected with the gas-liquid mixer, and a liquid flow meter is arranged on the liquid delivery pipeline, each of the gas-liquid mixers is communicated with one of the inflow sections of the casing through one of the reservoir simulation devices. The control system comprises at least a pressure gauge, an image acquisition device and a controller, the pressure gauge is arranged at least at an upstream end of the reservoir simulation device, a downstream end of the reservoir simulation device, the inflow section of the casing and a downstream end of each of the inflow sections of the casing, the image acquisition device is arranged at the inflow section of the casing, and the controller is used for controlling gas flow of the gas flow meter, liquid flow of the liquid flow meter and acquiring, analyzing and exporting gas flow data of the gas flow meter, liquid flow data of the liquid flow meter, pressure data of the pressure gauge and images of the image acquisition device.

[0006] The compact gas and deep coal bed gas cooperative exploitation simulation experiment device provided by the application, the gas delivery pipeline comprises a gas delivery pipeline and a first one-way valve and a first valve connected in series on the gas delivery pipeline.

[0007] The compact gas and deep coal bed gas cooperative exploitation simulation experiment device provided by the application, the liquid delivery pipeline comprises a liquid delivery pipeline and a second one-way valve and a second valve connected in series on the liquid delivery pipeline.

[0008] The compact gas and deep coal bed gas cooperative exploitation simulation experiment device provided by the application, the casing comprises a plurality of sub-casings and a plurality of visual three-way pipes, one of the interfaces of the visual three-way pipe is used for detachable connection with the downstream end of the reservoir simulation device, the other two interfaces of the visual three-way pipe are used for detachable connection with adjacent two sub-casings, the visual three-way pipe forms the inflow section of the casing, the visual three-way pipe is made of transparent material, or the visual three-way pipe and the sub-casing are made of transparent material.

[0009] The compact gas and deep coal bed gas cooperative exploitation simulation experiment device provided by the application, the oil pipe comprises a plurality of sub-oil pipes, adjacent two sub-oil pipes are detachably connected, and the visual three-way pipe at different depths is extended.

[0010] The reservoir simulation device is a sand filling hydraulic cylinder.

[0011] The gas supply assembly comprises an air compressor, a gas storage tank and a pressure reducing valve, the gas outlet of the air compressor is connected with the gas inlet of the gas storage tank, the gas outlet of the gas storage tank is connected with the pressure reducing valve, and the pressure reducing valve is connected with the upstream end of the gas delivery pipeline.

[0012] The liquid supply assembly comprises a liquid storage container and a liquid pump, the liquid inlet end of the liquid pump is connected with the liquid storage container, and the liquid outlet end of the liquid pump is connected with the liquid delivery pipeline.

[0013] The simulation experiment device for the cooperative exploitation of tight gas and deep coal bed gas further comprises a circulating pipeline, a fluid pump and a gas-liquid separator are arranged on the circulating pipeline, the fluid pump is connected between the top of the oil pipe and the inlet of the gas-liquid separator, and the liquid phase outlet of the gas-liquid separator is connected with the liquid storage container.

[0014] The image acquisition device comprises a high-speed camera.

[0015] The simulation experiment device for the cooperative exploitation of tight gas and deep coal bed gas has the following advantages: The application provides a simulation experiment device for the cooperative exploitation of tight gas and deep coal bed gas, a wellbore simulation device is used for simulating a wellbore structure, at least two inlets are arranged on the casing, the inlets are made of transparent material, so that an image acquisition device can record the internal fluid form, and a tubing is penetrated downward from the top of the casing to the inlets at different depths. The reservoir simulation device is used for simulating different reservoirs. The gas-liquid two-phase flow supply device comprises a gas supply assembly, a liquid supply assembly and at least two groups of gas-liquid delivery pipe junctions, each group of gas-liquid delivery pipe junctions comprises a gas delivery pipeline, a liquid delivery pipeline and a gas-liquid mixer, the upstream end of the gas delivery pipeline is connected with the gas supply assembly, the downstream end of the gas delivery pipeline is connected with the gas-liquid mixer, and a gas flow meter is arranged on the gas delivery pipeline, the upstream end of the liquid delivery pipeline is connected with the liquid supply assembly, the downstream end of the liquid delivery pipeline is connected with the gas-liquid mixer, and a liquid flow meter is arranged on the liquid delivery pipeline, and each gas-liquid mixer is communicated with one of the inlets on the casing through one reservoir simulation device. The control system at least comprises a pressure gauge, an image acquisition device and a control system, the pressure gauge is arranged at least at the upstream end of the reservoir simulation device, the downstream end of the reservoir simulation device, the inlets of the casing and the downstream end of each inlet of the casing, the image acquisition device is arranged at the inlets of the casing, and the control system is used for controlling the gas flow of the gas flow meter, the liquid flow of the liquid flow meter and collecting, analyzing and exporting the gas flow data of the gas flow meter, the liquid flow data of the liquid flow meter, the pressure data of the pressure gauge and the image of the image acquisition device. The simulation experiment device for the cooperative exploitation of tight gas and deep coal bed gas provided by the application can adjust the number of the gas-liquid delivery pipe junctions and the reservoir simulation devices according to the number of layers of the reservoir to be simulated, can independently adjust the percolation parameters, differential pressure control and productivity of each reservoir, respectively, can be communicated at the wellbore through the visual three-way joint, can simulate the interlayer coupling relationship under the condition of the cooperative production of double reservoirs, and can study the production layer switching strategy, mutual interference mechanism and dynamic response law under the condition of the combination of multiple reservoirs. The percolation parameters can be adjusted by adjusting the inner diameter of the reservoir simulation device, the type of the reservoir simulation particles, the filling length of the reservoir simulation particles and the loading degree. The differential pressure can be controlled by adjusting the gas delivery flow and the liquid delivery flow of the gas-liquid delivery pipe junction upstream of the reservoir simulation device. The control system is the core control center of the whole simulation experiment device, has the functions of pressure control, flow regulation, data acquisition, automatic feedback and experiment process control, and realizes the intelligent management of the experimental parameters. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0017] Figure 1 is a structural schematic diagram of a simulation experiment device for simulating the cooperative exploitation of tight gas and deep coalbed gas in a double reservoir according to an embodiment of the present application; Figure 2 is a structural schematic diagram of a simulation experiment device for simulating the cooperative exploitation of tight gas and deep coalbed gas in a three-reservoir according to an embodiment of the present application; Figure 3 is a structural schematic diagram of a reservoir simulation device according to an embodiment of the present application; Figure 4 is a structural schematic diagram of a visual three-way joint according to an embodiment of the present application; Figure 5 is a structural schematic diagram of a gas-liquid mixer according to an embodiment of the present application; Reference signs: 110: casing; 120: oil pipe; 130: visual three-way joint; 131: horizontal section; 132: vertical section; 210: glass beads; 220: sand filling hydraulic cylinder; 310: air compressor; 320: gas storage tank; 330: pressure reducing valve; 410: liquid storage container; 420: centrifugal pump; 510: gas conveying pipe; 520: first one-way valve; 530: first valve; 610: liquid conveying pipe; 620: second one-way valve; 630: second valve; 710: gas flow meter; 720: liquid flow meter; 730: pressure gauge; 740: high-speed camera; 750: controller; 810: gas-liquid separator; 820: diaphragm pump; 900: gas-liquid mixer; 910: liquid inlet; 920: gas inlet; 930: mixing cavity; 940: two-phase flow outlet. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0019] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements indicated thereby must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0020] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated thereby. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0021] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0022] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0023] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0024] The present application aims to solve the key technical problems existing in the current experimental study of the wellbore and reservoir of the two gas cooperative mining well, especially the existing experimental device generally cannot simultaneously and dynamically simulate the seepage interference between multiple reservoirs and the wellbore fluid response, which limits the in-depth exploration of the cooperative mining mechanism. In view of the problems in the process of cooperative mining of deep coalbed methane and tight sandstone gas, such as complex productivity response of different reservoirs, difficult prediction of wellbore multiphase flow state, unclear interlayer interference mechanism, etc., the present application provides a tight gas and deep coalbed methane cooperative mining simulation experiment device. The device can realize dynamic coupling simulation of the whole process of the reservoir-wellbore system, has the functions of multi-layer production layer switching control, differential pressure accurate control and flow data real-time acquisition, can effectively support the experimental research and mechanism verification of cooperative mining technology under complex gas reservoir conditions, and improve the restoration ability of the experimental system to the real working condition, and provide experimental basis and technical support for deep coalbed methane and tight sandstone gas cooperative mining.

[0025] The tight gas and deep coalbed methane cooperative mining simulation experiment device of the present application will be described below in combination with Figure 1 and Figure 2 .

[0026] The embodiment of the present application provides a tight gas and deep coalbed methane cooperative mining simulation experiment device, which comprises a wellbore simulation device, a reservoir simulation device, a gas-liquid two-phase flow supply device and a control system.

[0027] The wellbore simulation device comprises a casing 110 and a tubing 120, which are used to simulate the real wellbore structure. The casing 110 is provided with at least two inlet sections, the inlet sections are distributed along the axial direction of the casing 110, and at least the inlet sections are made of transparent material, of course, the whole casing 110 can also be made of transparent material. The tubing 120 penetrates into the casing 110 from the top of the casing 110 downward, and the bottom end of the tubing 120 can extend downward to the position of each depth of the casing 110, that is, the bottom end of the tubing 120 can extend to the position of each inlet section.

[0028] Reservoir simulation devices can be filled with reservoir simulation particles, such as glass beads 210, to simulate different permeability reservoir characteristics. For example, different permeability reservoirs can be simulated by varying the size of the glass beads 210, or different length or thickness reservoirs can be simulated by varying the length of the fill and the thickness of the fill, respectively.

[0029] The gas-liquid two-phase flow supply device includes a gas supply assembly, a liquid supply assembly, and at least two sets of gas-liquid delivery manifolds, each set of gas-liquid delivery manifolds including a gas delivery line, a liquid delivery line, and a gas-liquid mixer 900.

[0030] The gas supply assembly can be provided in one or more sets, and the gas supply assembly can supply gas to one gas delivery line or to two or more gas delivery lines simultaneously. Similarly, the liquid supply assembly can also be provided in one or more sets, and the liquid supply assembly can supply liquid to one liquid delivery line or to one or more liquid delivery lines simultaneously.

[0031] For example, in a specific embodiment, the gas-liquid two-phase flow supply device is provided with one set of gas supply assemblies and one set of liquid supply assemblies, the gas supply assemblies are connected to multiple gas delivery lines simultaneously, and the liquid supply assemblies are connected to multiple liquid delivery lines simultaneously.

[0032] That is, the upstream ends of the gas delivery lines in each set of gas-liquid delivery manifolds are connected to the gas supply assembly, and the upstream ends of the liquid delivery lines are connected to the liquid supply assembly. The downstream ends of the gas delivery lines and the downstream ends of the liquid delivery lines in each set of gas-liquid delivery manifolds are respectively connected to the corresponding interfaces of the corresponding gas-liquid mixer 900.

[0033] Each gas-liquid mixer 900 in each set of gas-liquid delivery manifolds is in communication with one of the inflow sections on the casing 110 through a reservoir simulation device.

[0034] A gas flow meter 710 is provided on each gas delivery line, which can measure the instantaneous flow of gas in the corresponding liquid delivery line and can be used to regulate the flow of gas in the corresponding gas delivery line.

[0035] A liquid flow meter 720 is provided on each liquid delivery line, which can measure the instantaneous flow of liquid in the corresponding liquid delivery line and can be used to regulate the flow of liquid in the corresponding liquid delivery line.

[0036] The control system comprises at least pressure gauges 730 arranged at least at the upstream end of the reservoir simulation device, the downstream end of the reservoir simulation device, the junction section of the casing 110, and the downstream end of each junction section of the casing 110, an image acquisition device arranged at the junction section of the casing 110, and a controller 750. The control system 750 is configured to control the flow rate of the gas flow meter 710, the liquid flow rate of the liquid flow meter 720, and can acquire, analyze, and export the gas flow data of the gas flow meter 710, the liquid flow data of the liquid flow meter 720, the pressure data of the pressure gauges 730, and the images of the image acquisition device.

[0037] In a specific embodiment, the simulation device for the coordinated exploitation of tight gas and deep coalbed methane is used to simulate a scenario of two layers, for example, a tight gas reservoir in the upper layer and a deep coalbed methane reservoir in the lower layer. The wellbore simulation device is constructed according to the depth of the two reservoirs to be simulated, that is, the wellbore simulation device is constructed in a scaled-down manner based on the depth of the two reservoirs to be simulated, and the junction section of the sleeve is arranged at the corresponding depth.

[0038] According to the permeability, thickness, length, and other parameters of the two reservoirs to be simulated, the corresponding reservoir simulation particles are filled into the two reservoir simulation devices to simulate the corresponding reservoirs. Then, the downstream ends of the two reservoir simulation devices are connected to the inlets of the corresponding junction sections, and the outlet of the gas-liquid separator 810 of the two sets of gas-liquid delivery pipe junctions is connected to the upstream end of the reservoir simulation device.

[0039] During the experiment, the gas supply assembly is opened, the gas is supplied to the corresponding gas-liquid mixer 900 through the gas delivery pipeline, the liquid supply assembly is opened, the liquid is delivered to the corresponding gas-liquid mixer 900 through the liquid delivery pipeline, and the gas and liquid are mixed in the gas-liquid mixer 900 to form a two-phase flow, which then enters the reservoir simulation device.

[0040] During the experiment, the on-off control of the gas delivery pipeline and the liquid delivery pipeline can be used to control whether the fluid of a certain reservoir flows into the wellbore, and different combinations can be switched to simulate the dynamic process of coordinated exploitation. The control system 750 is used to record the data returned by each pressure gauge 730 in real time, and calculate the pressure difference data between the adjacent two pressure gauges 730, while recording the instantaneous flow data and the cumulative flow data of the gas flow meter 710 and the liquid flow meter 720 in real time. The controller 750 is also used to acquire the dynamic video of the junction section recorded by the image acquisition device in real time, identify the gas-liquid flow pattern, interlayer interference zone, backflow, stagnation, and other flow phenomena.

[0041] The above embodiment takes two reservoirs as an example for illustration, and of course, three reservoirs, four reservoirs or more reservoirs can also be provided. Multiple rounds of comparison experiments can be carried out by adjusting the simulated reservoir parameters, switching the production layer sequence, adjusting the gas flow and liquid flow, etc. During the experiment, the double-layer, triple-layer or multi-layer structure can be quickly switched to realize the comparison analysis under the combined working condition of the reservoir. By shutting down the production layer layer by layer or adjusting the single-layer production capacity, the wellbore pressure response and the gas-liquid ratio change are studied to further reveal the coupling mechanism.

[0042] In some embodiments, the gas delivery pipeline includes a gas delivery pipe 510, and a first one-way valve 520 and a first valve 530 connected in series on the gas delivery pipe 510.

[0043] Specifically, the first one-way valve 520 and the first valve 530 are connected in series from the upstream to the downstream of the gas delivery pipe 510, and the gas flow meter 710 can be connected downstream of the first valve 530.

[0044] In some embodiments, the liquid delivery pipeline includes a liquid delivery pipe 610, and a second one-way valve 620 and a second valve 630 connected in series on the liquid delivery pipe 610.

[0045] Specifically, the second one-way valve 620 and the second valve 630 are connected in series from the upstream to the downstream of the liquid delivery pipe 610, and the liquid flow meter 720 can be connected downstream of the first valve 530.

[0046] The first valve 530 and the second valve 630 described above can be manual valves or electric control valves, used to control the on-off state of the corresponding pipeline, realize the production layer switching and flow path adjustment.

[0047] The first one-way valve 520 and the second one-way valve 620 described above are used to prevent backflow of gas or liquid, protect the gas supply assembly and the liquid supply assembly from the influence of reverse pressure fluctuation, and ensure stable operation of the experimental system.

[0048] The liquid flow meter 720 is used to measure the liquid flow into the corresponding gas-liquid mixer 900, support real-time data acquisition and dynamic analysis, and the gas flow meter 710 is used to monitor the gas flow into the corresponding gas-liquid mixer 900, and cooperates with the liquid flow meter 720 to complete the gas-liquid ratio control and mass conservation verification.

[0049] In some embodiments, the sleeve 110 described above can include a plurality of sub-sleeves and a plurality of visual three-way pipes 130, one interface of the visual three-way pipe 130 is used for detachable connection with the downstream end of the reservoir simulation device, the other two interfaces of the visual three-way pipe 130 are used for detachable connection with the adjacent two sub-sleeves, the visual three-way pipe 130 forms the confluence section of the sleeve 110, the visual three-way pipe 130 is of transparent material, or the visual three-way pipe 130 and the sub-sleeve are both of transparent material.

[0050] Specifically, taking the case of setting three reservoir simulators, the casing 110 can include four sub-casings arranged along the vertical direction and three visualizing tees 130 arranged between adjacent two sub-casings.

[0051] The visualizing tee 130 can include a horizontal section 131 extending to the left and a vertical section 132, a top end of the vertical section 132 being connected to a bottom end of an upper sub-casing, and a bottom end being connected to a top end of a lower sub-casing.

[0052] The vertical section 132 of the visualizing tee 130 is lengthened to ensure that the vertical height of the converging section is not less than 30 cm, providing a sufficient visual window. The multiple visualizing tees 130 are distributed along the vertical direction to support the connection of double-layer, triple-layer or multi-layer gas-liquid manifold, forming clear images of gas-liquid flow trajectory, jet impact, intersection disturbance, etc. The visualizing tee 130 is detachably connected to the sub-casing and the reservoir simulator, facilitating cleaning, equipment replacement and installation of different experimental modules. The image acquisition device can be aligned with the visualizing tee 130 for shooting, cooperating with a backlight system and a high-frame-rate acquisition software to realize clear flow pattern capture.

[0053] Through the device, the dynamic processes of different reservoir gas-liquid two-phase flow in the wellbore, such as coalescence, disturbance, entrainment and alternation, can be observed, and the action mechanism of interference intensity and relative flow control strategy can be analyzed. The device not only can restore the physical structure of the reservoir, but also can build a composite reservoir system with interlayer pressure gradient and heterogeneous structure by combining multiple devices.

[0054] In some embodiments, the tubing 120 is used to construct a main channel of the wellbore simulator, connecting each reservoir production layer to the ground treatment system to realize unified coalescence and transportation of multi-reservoir production fluid. The above-mentioned tubing 120 includes multiple sub-tubings, and adjacent two sub-tubings are detachably connected. By selecting different numbers and lengths of sub-tubings for combination, the bottom end of the tubing 120 can be extended downward to the visualizing tee 130 at different depths.

[0055] In some embodiments, the reservoir simulator can be a sand-filled hydraulic cylinder 220.

[0056] The sand-filled hydraulic cylinder 220 is internally filled with reservoir simulation particles with particle sizes calculated according to the Kozeny-Carman equation, for example, glass beads 210, to simulate different permeability reservoir characteristics. By replacing different combinations of inner diameters, lengths and glass bead 210 particle sizes, reservoirs with different thicknesses, lengths and physical parameters can be simulated. The hydraulic system is used to load the glass beads 210 to ensure the filling density of the glass beads 210 and improve the simulation accuracy.

[0057] The outer sleeve of the sand filling hydraulic cylinder 220 is used to constrain the reservoir boundary, and different inner diameters can change the filling thickness of the glass beads 210 to simulate different formation thicknesses. The sand filling section length is adjustable to simulate different reservoir permeation resistances. The hydraulic loading device can ensure the compaction degree of sand filling to simulate the pore structure under the formation stress. The pressure gauges 730 arranged upstream and downstream of the sand filling hydraulic cylinder 220 are used to collect the permeation pressure drop and output parameters before and after the section.

[0058] The sand filling hydraulic cylinder 220 can realize the regulation of the reservoir permeability, and by adjusting the length and inner and outer diameters of the filling section, different reservoir development thicknesses and lengths can be simulated, so that multiple reservoir combinations can be constructed to realize controllable simulation of the permeation characteristics between multiple reservoirs.

[0059] In some embodiments, the gas supply assembly includes an air compressor 310, a gas storage tank 320, and a pressure reducing valve 330, the gas outlet of the air compressor 310 is connected with the gas inlet of the gas storage tank 320, the gas outlet of the gas storage tank 320 is connected with the pressure reducing valve 330, and the pressure reducing valve 330 is connected with the upstream end of the gas delivery pipeline.

[0060] The air compressor 310 is used to provide a high-pressure gas source required by the experiment, and by controlling the output pressure, the reservoir gas production state under different depth conditions can be simulated. The gas storage tank 320 is a temporary storage unit for the gas used in the experiment, which can balance the gas supply pressure fluctuation and provide a stable gas source for the gas-liquid mixer 900 and the reservoir gas system. The pressure reducing valve 330 is used to accurately control the pressure of the fluid before entering the reservoir or the wellbore, so as to ensure that the experimental conditions are within the set range and improve the stability and repeatability of the experimental data.

[0061] In some embodiments, the liquid supply assembly includes a liquid storage container 410 and a liquid pump, the liquid inlet end of the liquid pump is connected with the liquid storage container 410, and the liquid outlet end of the liquid pump is connected with the liquid delivery pipeline.

[0062] The above-mentioned liquid pump can be a centrifugal pump 420, which is used to provide continuous circulation and lifting power of the liquid in the system to meet the experimental operation requirements such as liquid injection of the reservoir simulation device and liquid supplement of the wellbore simulation device. The liquid storage container 410 is used to store the liquid medium used in the experiment for circulation by the centrifugal pump 420, so as to ensure the continuity and adjustability of the liquid supply.

[0063] In some embodiments, a circulating pipeline is further included, a fluid pump and a gas-liquid separator 810 are arranged on the circulating pipeline, the fluid pump is connected between the top of the oil pipe 120 and the inlet of the gas-liquid separator 810, and the liquid phase outlet of the gas-liquid separator 810 is connected with the liquid storage container 410.

[0064] The fluid pump can be a diaphragm pump 820 for injecting the gas-liquid two-phase flow produced by the wellbore simulation device into the gas-liquid separator 810, which is used for efficient separation of the gas-liquid two-phase flow, ensuring stable operation of the subsequent fluid circulation system and avoiding interference of gas-liquid mixed transportation on the pump and pipeline system. The separated liquid can be recycled back into the liquid storage container 410.

[0065] In some embodiments, the image acquisition device includes a high-speed camera 740 arranged on one side of each visualization tee joint 130 for recording the instantaneous dynamic process of the multi-reservoir fluid during the wellbore intersection process, thereby providing image evidence and data support for interlayer interference research.

[0066] In one specific embodiment, the tight gas and deep coalbed methane co-exploration simulation experimental device provided by the present application mainly includes a gas-liquid separator 810, a diaphragm pump 820, a casing 110, a tubing 120, a pressure gauge 730, a controller 750, a gas-liquid mixer 900, a visualization tee joint 130, a sand filling hydraulic cylinder 220, a liquid flowmeter 720, a gas flowmeter 710, a first valve 530, a first check valve 520, a second valve 630, a second check valve 620, a pressure reducing valve 330, a centrifugal pump 420, a gas storage tank 320, a liquid storage container 410, an air compressor 310, and a high-speed camera 740.

[0067] The gas source of the tight gas and deep coalbed methane co-exploration simulation experimental device is provided by the air compressor 310, the flow is monitored by the gas flowmeter 710 and the output flow is adjusted, and the pressure is buffered by the gas storage tank 320. The gas then enters the reservoir simulation device through the outlet in the gas-liquid mixer 900.

[0068] The liquid is supplied by the liquid storage container 410, and the centrifugal pump 420 is responsible for the delivery and injection of water, which has the characteristics of stable flow and controllable pressure, and the liquid flowmeter 720 is used for real-time monitoring of the liquid injection flow.

[0069] The casing 110 and the tubing 120 together constitute the wellbore simulation device, and the tubing 120 changes the length by selecting different numbers or lengths of sub-tubings to connect each layer of producing formation. The visualization tee joint 130 is made of transparent acrylic or tempered glass material, and the vertical section 132 is lengthened to provide an observable space. Each gas delivery pipeline is provided with a first valve 530 and a first check valve 520, and each liquid delivery pipeline is provided with a second valve 630 and a second check valve 620, so as to realize single-layer or multi-layer combined production flow switching and avoid reverse interference. The high-speed camera 740 is installed on the visualization tee joint 130 for recording the flow pattern and interference evolution process when the multi-layer fluid converges.

[0070] The gas-liquid mixer 900 is provided with a liquid inlet 910 and a gas inlet 920 for forming a gas-liquid two-phase flow, and a two-phase flow outlet 940 is communicated with the reservoir simulation device. The top of the wellbore simulation device is separated from the mixed fluid by the gas-liquid separator 810, and the gas and the liquid are respectively discharged for recycling or analysis.

[0071] The controller 750 is used for unified control of various sensors, execution elements and data acquisition devices, including the liquid flow meter 720, the gas flow meter 710, the pressure meter 730, the liquid pump, the fluid pump and the high-speed camera 740. The controller 750 is the core control center of the whole simulation experiment device, has the functions of pressure control, flow regulation, data acquisition, automatic feedback and experiment process control, and realizes intelligent management of experiment parameters. Through linkage with the high-speed camera 740, the gas flow meter 710, the liquid flow meter 720, the pressure meter 730 and other sensing devices, automatic monitoring, data recording and visual analysis of the experiment process are realized.

[0072] Referring to Figure 1 , Figure 1 A structural schematic diagram of the simulation experiment device for the cooperative exploitation of tight gas and deep coalbed gas is provided, which shows the overall structural layout of the simulation experiment device in the simulation of the coupled exploitation of two layers of reservoirs. The structure is used for simulating the simulation experiment device for the cooperative exploitation of tight gas and deep coalbed gas with upper and lower production layers, and can study the dynamic interference mechanism of the upper and lower production layers under different flow rates and pressure differences.

[0073] The simulation experiment device includes two upper and lower sand-filled hydraulic cylinders 220, each of which is used as an independent reservoir simulation device and is internally filled with glass beads 210 with a particle size calculated by the Kozeny-Carman equation. The upper and lower layers simulate the percolation characteristics of the tight sandstone gas layer and the coalbed gas layer, respectively.

[0074] The two reservoirs are sequentially connected in the vertical direction through the visual three-way joint 130 to realize separate control of the production capacity of the layers, and the opening state of the production layer can be controlled independently.

[0075] The whole simulation experiment device forms a two-phase flow by the gas-liquid mixer 900, and the two-phase flow passes through each reservoir simulation device from left to right and flows into the wellbore simulation device. The pressure meters 730 are arranged at positions corresponding to the visual three-way joints 130 and the positions between adjacent two visual three-way joints 130 at both ends of each reservoir simulation device, the wellbore simulation device and the wellbore simulation device, respectively, for real-time monitoring of the differential pressure response. The structure is suitable for systematic study of the interference between the double-layer reservoirs, the cooperative relationship of the production capacity and the wellbore response law.

[0076] Referring to Figure 2 , Figure 2 For Figure 1The extension of the structure shown, an additional reservoir simulation device is added for studying the complex interference relationship between the three layers of reservoirs and the interlayer response law.

[0077] The simulation experiment device includes three independent sand filling hydraulic cylinders 220, respectively representing the upper, middle and lower three reservoirs. Each reservoir simulation device is provided with an independent gas-liquid delivery manifold and is connected to the inlet end of each visual three-way valve 130. Each reservoir is filled with glass beads 210 to regulate different permeabilities, and a hydraulic loading system is used to adjust the reservoir density.

[0078] The three reservoir simulation devices are connected in sequence in the vertical direction to each visual three-way valve 130, so that the three layers of fluid can be simultaneously or staggered into the visual three-way valve 130 for observation and analysis of the flow structure and gas-liquid interface shape under different combinations. The high-speed camera 740 is aimed at the visual three-way valve 130 for shooting, which is used for subsequent image recognition and data analysis.

[0079] The three-layer convergence structure is closer to the real well condition of multi-reservoir than the double-layer structure, and is suitable for simulating the multi-reservoir joint exploitation scene such as coal-sand-shale, and is an important platform for studying the complex interlayer coupling mechanism.

[0080] Figure 5 The structure of the gas-liquid mixer 900 is a key module for inputting two-phase flow state in the simulation experiment device.

[0081] The gas-liquid mixer 900 mainly includes a liquid inlet 910, a gas inlet 920, a two-phase flow outlet 940 and a mixing chamber 930. The liquid inlet 910 can be located on the left side of the mixing chamber 930, the two-phase flow outlet 940 can be located on the right side of the mixing chamber 930, and the gas inlet 920 can be located on the top of the mixing chamber 930. The liquid enters the mixing chamber 930 along the horizontal direction through the liquid inlet 910 after passing through the liquid flow meter 720, and the gas enters the mixing chamber 930 through the gas inlet 920 after passing through the gas flow meter 710. The two-phase flow in the mixing chamber 930 forms a bubble flow, a slug flow or a mist flow, and the two-phase flow outlet 940 of the gas-liquid mixer 900 is connected to the sand filling hydraulic cylinder 220, realizing the effect of simulating the injection of mixed fluid into the reservoir.

[0082] The gas-liquid mixer 900 can replace internal structural elements such as nozzles, turbulence plates and throttle holes according to experimental requirements to control the gas-liquid ratio, jet intensity and initial flow pattern.

[0083] The device is used to form a controllable two-phase mixed flow before the experiment, to ensure that the initial conditions of each experiment are consistent, and to provide a unified starting point for the dynamic evolution research of the wellbore-reservoir system.

[0084] The experimental steps of the tight gas and deep coalbed methane co-exploration simulation experiment device provided by the application are as follows: Step 1: Select the target number of simulation layers (e.g. two or three layers), install gas supply components, liquid supply components, and corresponding number of gas-liquid delivery manifolds; Step 2: According to the target reservoir permeability, fill the reservoir simulation device with glass beads 210 of corresponding particle size, set different formation thicknesses and flow paths, start the hydraulic device of the reservoir simulation device, load the glass bead 210 filling section to ensure its density; Step 3: Install the reservoir simulation device, connect the upstream end of the reservoir simulation device to the two-phase flow outlet 940 of the gas-liquid mixer 900 of the corresponding gas-liquid delivery manifold, and connect the downstream end of the reservoir simulation device to the corresponding visual three-way valve 130 on the casing 110; Step 4: Install gas flow meter 710, liquid flow meter 720, pressure gauge 730 and high-speed camera 740, and connect gas flow meter 710, liquid flow meter 720, high-speed camera 740, pump-like equipment, valves, etc. on the gas-liquid delivery manifold to the controller 750, install the high-speed camera 740 to one side of the visual three-way valve 130 and adjust to the appropriate angle to align with the visual three-way valve 130 area.

[0085] Step 5: Turn on the air compressor 310 and adjust the output pressure to the set value, inject gas into the system; Step 6: Start the centrifugal pump 420 and inject liquid into the system; Step 7: After the gas and liquid are mixed in the gas-liquid mixer 900 to form a two-phase flow, they enter the reservoir simulation device; Step 8: Control whether a certain reservoir fluid flows into the wellbore simulation device through the valve on the gas-liquid delivery manifold, and switch different combinations to simulate the cooperative production dynamic process.

[0086] Step 9: Record real-time pressure data, instantaneous and cumulative liquid and gas flow rates; Step 10: High-speed camera 740 records multi-layer confluence dynamic video, identifies gas-liquid flow pattern, interlayer interference zone, backflow, stagnation and other flow phenomena; It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced equivalently. Such modifications or replacements do not change the essence of the corresponding technical solutions, which should be covered in the scope of the claims and the specification of the present application. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A simulation experiment device for the coordinated exploitation of tight gas and deep coalbed methane, characterized in that, The application relates to a wellbore simulation device, a reservoir simulation device, a gas-liquid two-phase flow supply device and a control system. The wellbore simulation device comprises a casing (110) and a tubing (120), the casing (110) is provided with at least two merging sections, and at least the merging sections of the casing (110) are made of transparent material, and the tubing (120) is used for penetrating into different merging sections from the top of the casing (110) downwards. The reservoir simulation device is used for filling reservoir simulation particles to simulate different permeability reservoir characteristics. The gas-liquid two-phase flow supply device comprises a gas supply assembly, a liquid supply assembly and at least two groups of gas-liquid delivery pipe junctions, each group of the gas-liquid delivery pipe junctions comprises a gas delivery pipeline, a liquid delivery pipeline and a gas-liquid mixer (900), the upstream end of the gas delivery pipeline is connected with the gas supply assembly, the downstream end of the gas delivery pipeline is connected with the gas-liquid mixer (900), and a gas flow meter (710) is arranged on the gas delivery pipeline, the upstream end of the liquid delivery pipeline is connected with the liquid supply assembly, the downstream end of the liquid delivery pipeline is connected with the gas-liquid mixer (900), and a liquid flow meter (720) is arranged on the liquid delivery pipeline, and each gas-liquid mixer (900) is communicated with one of the merging sections of the casing (110) through one reservoir simulation device. The control system comprises at least a pressure gauge (730), an image acquisition device and a controller (750), the pressure gauge (730) is arranged at least at the upstream end of the reservoir simulation device, the downstream end of the reservoir simulation device, the merging sections of the casing (110) and the downstream end of each merging section of the casing (110), the image acquisition device is arranged at the merging sections of the casing (110), and the controller (750) is used for controlling the gas flow of the gas flow meter (710), the liquid flow of the liquid flow meter (720) and acquiring, analyzing and exporting the gas flow data of the gas flow meter (710), the liquid flow data of the liquid flow meter (720), the pressure data of the pressure gauge (730) and the image of the image acquisition device.

2. The apparatus according to claim 1, wherein, The gas delivery pipeline comprises a gas delivery pipe (510), a first one-way valve (520) and a first valve (530) which are connected in series on the gas delivery pipe (510).

3. The apparatus according to claim 1, wherein, The liquid delivery pipeline comprises a liquid delivery pipe (610), a second one-way valve (620) and a second valve (630) which are connected in series on the liquid delivery pipe (610).

4. The apparatus according to claim 1, wherein, The casing (110) comprises a plurality of sub-casings and a plurality of visualized tees (130), one interface of the visualized tee (130) is used for being detachably connected with the downstream end of the reservoir simulation device, the other two interfaces of the visualized tee (130) are used for being detachably connected with adjacent two sub-casings, the visualized tee (130) forms the merging section of the casing (110), the visualized tee (130) is made of transparent material, or the visualized tee (130) and the sub-casing are both made of transparent material.

5. The apparatus according to claim 4, wherein, The oil pipe (120) comprises a plurality of sub-oil pipes, and adjacent two sub-oil pipes are detachably connected, and are used for extending to the visualization tee joint (130) at different depths. 6.The apparatus for simulating the exploitation of tight gas and deep coalbed methane according to claim 1, characterized in that, The reservoir simulation device is a sand filling hydraulic cylinder (220).

7. The apparatus according to claim 1, wherein, The gas supply assembly comprises an air compressor (310), a gas storage tank (320) and a pressure reducing valve (330), the gas outlet of the air compressor (310) is connected with the gas inlet of the gas storage tank (320), the gas outlet of the gas storage tank (320) is connected with the pressure reducing valve (330), and the pressure reducing valve (330) is connected with the upstream end of the gas delivery pipeline. 8.The apparatus for simulating the exploitation of tight gas and deep coalbed methane according to claim 1, characterized in that, The liquid supply assembly comprises a liquid storage container (410) and a liquid pump, the liquid inlet end of the liquid pump is connected with the liquid storage container (410), and the liquid outlet end of the liquid pump is connected with the liquid delivery pipeline.

9. The apparatus according to claim 8, characterized in that, Further comprising a circulating pipeline, a fluid pump and a gas-liquid separator (810) are arranged on the circulating pipeline, the fluid pump is connected between the top of the oil pipe (120) and the inlet of the gas-liquid separator (810), and the liquid phase outlet of the gas-liquid separator (810) is connected with the liquid storage container (410). 10.The apparatus for simulating the exploitation of tight gas and deep coalbed methane according to claim 1, characterized in that, The image acquisition device comprises a high-speed camera (740).

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