Experimental apparatus and methods for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs

Abstract

This invention discloses an experimental apparatus and method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs. The apparatus includes: a three-dimensional artificial core model, comprising a sealing layer and an artificial core, with the sealing layer covering the artificial core; a hydrogen sulfide detection mechanism, including a first hydrogen sulfide detector and multiple hydrogen sulfide probes, one end of which penetrates the sealing layer and extends into multiple detection areas within the artificial core, and the other end is electrically connected to the first hydrogen sulfide detector; at least one injection-production pipe, one end of which penetrates the sealing layer and extends into the artificial core; and a gas injection mechanism connected to the other end of the injection-production pipe. This invention can simulate the hydrogen sulfide washing process in actual gas reservoirs and can monitor the concentration changes of hydrogen sulfide in each detection area in real time, obtaining the hydrogen sulfide distribution in the artificial core. Therefore, this invention can be used to study the process and mechanism of hydrogen sulfide washing, providing preliminary predictions and parameter design for hydrogen sulfide washing experiments in real gas reservoirs, and interpreting the washing results.

Description

Technical Field

[0001] This invention relates to the field of natural gas extraction and storage technology, and in particular, to an experimental apparatus and method for studying the hydrogen sulfide washing mechanism of sulfur-containing gas reservoirs. Background Technology

[0002] Currently, there are many high-sulfur gas reservoirs in the late stages of development. When constructing gas storage facilities using these reservoirs, hydrogen sulfide washing is required. This involves injecting clean natural gas into the sulfur-containing gas reservoir, mixing it for a period of time, and then extracting the sulfur-containing natural gas from the reservoir. After several rounds of injecting clean gas and extracting it, the hydrogen sulfide content in the reservoir is reduced to below the standard level, thus meeting the requirements for storing natural gas in subsequent gas storage facilities. However, the mechanism of hydrogen sulfide washing is not yet clear, and the distribution of hydrogen sulfide during the washing process of sulfur-containing gas reservoirs is also unclear, making it impossible to visually observe the distribution of hydrogen sulfide.

[0003] Current research on the purification of sulfur-containing gas reservoirs relies heavily on numerical simulations because hydrogen sulfide is colorless and cannot be distinguished from natural gas when mixed together. Experimental testing makes it impossible to observe the distribution of hydrogen sulfide.

[0004] In existing technologies, experimental devices for washing hydrogen sulfide from natural gas in gas storage facilities use a core holder to hold the rock sample. A mixture of natural gas and hydrogen sulfide is introduced into the core holder until the sample is saturated. Then, natural gas is introduced into the core holder to wash away the hydrogen sulfide. While this method can effectively wash away hydrogen sulfide from the natural gas in the storage facility, it only obtains the final content of the washed-out hydrogen sulfide and cannot determine the distribution and variations of hydrogen sulfide within the core. Summary of the Invention

[0005] The purpose of this invention is to provide an experimental apparatus and method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs, in order to solve the technical problem that current hydrogen sulfide washing experiments can only obtain the final content of hydrogen sulfide that has already been washed, but cannot obtain the distribution and variation of hydrogen sulfide inside the core.

[0006] The above-mentioned objectives of the present invention can be achieved by the following technical solutions:

[0007] This invention provides an experimental apparatus for studying the hydrogen sulfide washing mechanism of sulfur-bearing gas reservoirs, comprising: a three-dimensional artificial core model, including a sealing layer and an artificial core, wherein the sealing layer covers the artificial core; a hydrogen sulfide detection mechanism, including a first hydrogen sulfide detector and multiple hydrogen sulfide probes, one end of each probe penetrating the sealing layer and extending into multiple detection areas within the artificial core, and the other end of each probe being electrically connected to the first hydrogen sulfide detector; at least one injection-production pipe, one end of which penetrates the sealing layer and extends into the artificial core; and a gas injection mechanism connected to the other end of the injection-production pipe.

[0008] In an embodiment of the present invention, the artificial core comprises multiple core layers, which are stacked and spliced ​​together in a vertical direction, and each core layer has a different permeability and / or porosity.

[0009] In an embodiment of the present invention, the sealing layer is cast onto the artificial rock core by a sealing material.

[0010] In an embodiment of the present invention, there are multiple injection and production pipes, which are distributed near the edge of the artificial core.

[0011] In an embodiment of the present invention, the injection-production pipe is provided with an injection-production control valve and a pressure monitoring structure.

[0012] In an embodiment of the present invention, the hydrogen sulfide detection mechanism further includes a processing terminal, which is electrically connected to the first hydrogen sulfide detector. The processing terminal is used to analyze and process the detection signal from the first hydrogen sulfide detector to generate a hydrogen sulfide distribution map of the artificial core.

[0013] In an embodiment of the present invention, the gas injection mechanism includes a natural gas pipeline, a hydrogen sulfide-containing natural gas pipeline, and an injection pump. The natural gas pipeline connects the injection-production pipe to the natural gas supply structure, and the hydrogen sulfide-containing natural gas pipeline connects the injection-production pipe to the hydrogen sulfide-containing natural gas supply structure. The injection pump is used to provide transportation power for transporting natural gas from the natural gas pipeline to the injection-production pipe and / or for transporting hydrogen sulfide from the hydrogen sulfide-containing natural gas pipeline to the injection-production pipe.

[0014] In an embodiment of the present invention, a natural gas control valve is provided on the natural gas pipeline, and a hydrogen sulfide-containing natural gas control valve is provided on the hydrogen sulfide-containing natural gas pipeline.

[0015] In an embodiment of the present invention, the experimental apparatus further includes a gas recovery structure, which is connected to the injection-production pipe via a gas collection pipeline. The gas collection pipeline is equipped with a gas collection control valve and a production pump.

[0016] In an embodiment of the present invention, a second hydrogen sulfide detector is also provided on the gas sampling pipeline.

[0017] In an embodiment of the present invention, the experimental apparatus further includes a vacuuming structure, which is used to connect at least one of the injection-production pipes to evacuate the artificial core.

[0018] In an embodiment of the present invention, the experimental apparatus further includes a housing and a third hydrogen sulfide detector. The three-dimensional artificial rock core model is placed inside the housing, and the detection end of the third hydrogen sulfide detector extends into the gap between the housing and the three-dimensional artificial rock core model.

[0019] This invention also provides an experimental method for studying the hydrogen sulfide washing mechanism of sulfur-bearing gas reservoirs, comprising the following steps: S3, injecting hydrogen sulfide-containing natural gas into an artificial core until the pressure in the artificial core reaches a first preset pressure, then stopping the injection of hydrogen sulfide-containing natural gas; S4, placing the artificial core for a preset time until the internal pressure of the artificial core reaches equilibrium; S5, recording the concentration of hydrogen sulfide in each detection area of ​​the artificial core; S6, injecting natural gas into the artificial core until the pressure in the artificial core reaches a second preset pressure, then stopping the injection, and monitoring the change of hydrogen sulfide concentration in each detection area over time in real time; S7, when the concentration of hydrogen sulfide in each detection area no longer changes, gas extraction is carried out, and the change of hydrogen sulfide concentration in each detection area is also monitored in real time during the gas extraction process; S8, repeating steps S6 and S7, and monitoring the change of hydrogen sulfide concentration in each detection area in real time.

[0020] In an embodiment of the present invention, before step S3, the following steps are also included: S1, detecting the sealing performance of the sealing layer covering the artificial rock core to ensure that the sealing performance of the sealing layer meets the requirements; S2, evacuating the artificial rock core.

[0021] In an embodiment of the present invention, the first preset pressure is 2 MPa; the second preset pressure is 3 MPa.

[0022] In an embodiment of the present invention, steps S6 and S7 are repeated until the hydrogen sulfide concentration is below 1 mg / m³. 3 Or the concentration of hydrogen sulfide required for the study.

[0023] In an embodiment of the present invention, after step S8, the following steps are also included: S9, interpolating the recorded hydrogen sulfide concentrations of each detection area and assigning different colors to different hydrogen sulfide concentrations, thereby obtaining a hydrogen sulfide distribution map of the artificial rock core.

[0024] The features and advantages of this invention are:

[0025] This invention provides an experimental apparatus and method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs. A three-dimensional artificial core model is formed by covering an artificial core with a sealing layer. An injection-production pipe penetrating the sealing layer and multiple hydrogen sulfide probes are installed. This allows a mixture of natural gas and hydrogen sulfide supplied by an injection mechanism to be introduced into the artificial core first. Then, the natural gas supplied by the injection mechanism washes away the hydrogen sulfide in the artificial core, simulating the actual hydrogen sulfide washing process in a gas reservoir. A first hydrogen sulfide detector collects the detection signals from the multiple hydrogen sulfide probes, enabling real-time monitoring of hydrogen sulfide concentration changes in each detection area and obtaining the hydrogen sulfide distribution in the artificial core during the washing process. Therefore, this invention can be used to study the process and mechanism of hydrogen sulfide washing, providing preliminary predictions and parameter design for real gas reservoir hydrogen sulfide washing experiments, and interpreting the washing results. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the experimental apparatus used to study the hydrogen sulfide washing mechanism in a sulfur-containing gas reservoir according to one embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the structure of the artificial rock core in this invention.

[0029] Figure 3 This is a schematic diagram showing the distribution of multiple detection areas in the artificial rock core of this invention.

[0030] Figure 4 This is a schematic diagram showing the distribution of multiple hydrogen sulfide probes and multiple injection / production tubes on an artificial core in this invention.

[0031] Figure 5 This is a schematic diagram of the experimental apparatus used to study the hydrogen sulfide washing mechanism in a sulfur-containing gas reservoir, according to another embodiment of the present invention.

[0032] Figure 6 This is a schematic diagram of the experimental apparatus used to study the hydrogen sulfide washing mechanism in a sulfur-containing gas reservoir, in another embodiment of the present invention.

[0033] Figure 7 This is a schematic diagram of the experimental apparatus used to study the hydrogen sulfide washing mechanism in a sulfur-containing gas reservoir, according to another embodiment of the present invention.

[0034] In the picture:

[0035] 1. Three-dimensional artificial rock core model; 101. Artificial rock core; 1011. Rock core layer; 1011'. Rock core layer; 1012. Detection area; 102. Sealing layer;

[0036] 2. Injection and production tubing; 201. Pressure monitoring structure; 202. Injection and production control valve;

[0037] 3. Gas injection mechanism; 301. Natural gas pipeline; 302. Hydrogen sulfide-containing natural gas pipeline; 303. Injection pump; 304. Natural gas control valve; 305. Hydrogen sulfide-containing natural gas control valve; 306. Natural gas supply structure; 307. Hydrogen sulfide-containing natural gas supply structure;

[0038] 4. Hydrogen sulfide detection facility; 401. First hydrogen sulfide detector; 402. Hydrogen sulfide probe; 403. Processing terminal;

[0039] 5. Gas recovery structure; 6. Gas collection pipeline; 7. Gas collection control valve; 8. Gas collection pump; 9. Vacuum pumping structure; 10. Second hydrogen sulfide detector; 11. Housing; 12. Third hydrogen sulfide detector; 13. Gas recovery pipeline. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Implementation Method 1

[0042] like Figure 1 As shown, this invention provides an experimental apparatus for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs, comprising: a three-dimensional artificial core model 1, including a sealing layer 102 and an artificial core 101, the sealing layer 102 covering the artificial core 101; and a hydrogen sulfide detection mechanism 4, including a first hydrogen sulfide detector 401 and multiple hydrogen sulfide probes 402, one end of each probe penetrating the sealing layer 102 and extending into multiple detection areas 1012 within the artificial core 101 (see...). Figure 3 As shown), the other end of multiple hydrogen sulfide probes 402 is electrically connected to the first hydrogen sulfide detector 401; at least one injection-production pipe 2, one end of which penetrates the sealing layer 102 and enters the artificial core 101; and a gas injection mechanism 3, which is connected to the other end of the injection-production pipe 2.

[0043] The experimental apparatus of the present invention for studying the hydrogen sulfide washing mechanism of sulfur-bearing gas reservoirs forms a three-dimensional artificial core model 1 by covering an artificial core 101 with a sealing layer 102. An injection-production pipe 2 penetrating the sealing layer 102 and extending into the artificial core 101, along with multiple hydrogen sulfide probes 402, allows hydrogen sulfide-containing natural gas (i.e., a mixture of natural gas and hydrogen sulfide) provided by the gas injection mechanism 3 to first be introduced into the artificial core 101. Then, the gas injection mechanism 3 provides natural gas to wash away the sulfur in the artificial core 101. Hydrogen sulfide is used for washing, which can simulate the actual hydrogen sulfide washing process in a gas reservoir. The detection signals of multiple hydrogen sulfide probes 402 are collected by the first hydrogen sulfide detector 401, so that the concentration change of hydrogen sulfide in each detection area 1012 can be monitored in real time, and the distribution of hydrogen sulfide in artificial core 101 during the hydrogen sulfide washing process can be obtained. Therefore, the present invention can be used to study the process and mechanism of hydrogen sulfide washing, provide preliminary prediction and parameter design for hydrogen sulfide washing experiments in real gas reservoirs, and interpret the washing results.

[0044] like Figure 1 As shown, in an embodiment of the present invention, the hydrogen sulfide detection mechanism 4 further includes a processing terminal 403, which is electrically connected to the first hydrogen sulfide detector 401. The processing terminal 403 is used to analyze and process the detection signal from the first hydrogen sulfide detector 401 to generate a hydrogen sulfide distribution map of the artificial core 101. Specifically, the processing terminal 403 can be a computer. The hydrogen sulfide distribution map can be obtained, as in some embodiments of the present invention, by interpolating the recorded hydrogen sulfide concentrations of each detection area 1012 and assigning different colors to different hydrogen sulfide concentrations. By using different colors to represent different hydrogen sulfide concentrations, the distribution of hydrogen sulfide in the artificial core 101 can be more intuitively represented.

[0045] like Figure 1 As shown, in an embodiment of the present invention, the gas injection mechanism 3 includes a natural gas pipeline 301, a hydrogen sulfide-containing natural gas pipeline 302, and an injection pump 303. The natural gas pipeline 301 connects the injection-production pipe 2 and the natural gas supply structure 306. The hydrogen sulfide-containing natural gas pipeline 302 connects the injection-production pipe 2 and the hydrogen sulfide-containing natural gas supply structure 307. The injection pump 303 is used to provide power for transporting natural gas from the natural gas pipeline 301 to the injection-production pipe 2 and / or for transporting hydrogen sulfide from the hydrogen sulfide-containing natural gas pipeline 302 to the injection-production pipe 2.

[0046] The hydrogen-sulfur-containing natural gas supplied by the hydrogen-sulfur-containing natural gas supply structure 307 is first injected into the artificial core 101 through the hydrogen-sulfur-containing natural gas pipeline 302 from the injection-production pipe 2 via the injection pump 303. Then, the natural gas supplied by the natural gas supply structure 306 is injected into the artificial core 101 through the natural gas pipeline 301 from the injection-production pipe 2 via the injection pump 303.

[0047] Specifically, a natural gas control valve 304 is installed on the natural gas pipeline 301, and a hydrogen sulfide-containing natural gas control valve 305 is installed on the hydrogen sulfide-containing natural gas pipeline 302. Optionally, the natural gas control valve 304 is installed on the natural gas supply structure 306, and the hydrogen sulfide-containing natural gas control valve 305 is installed on the hydrogen sulfide-containing natural gas supply structure 307.

[0048] like Figure 1 As shown in the embodiment of the present invention, the experimental apparatus further includes a gas recovery structure 5. The gas recovery structure 5 is connected to the injection-production pipe 2 via a gas extraction pipeline 6. The gas extraction pipeline 6 is equipped with a gas extraction control valve 7 and a production pump 8. After the natural gas injection stops, the gas in the artificial core 101 can be extracted through the gas extraction pipeline 6 to the gas recovery structure 5 by opening the gas extraction control valve 7 and using the production pump 8. This achieves the washing of hydrogen sulfide in the artificial core 101 and prevents the gas from being emitted into the environment and polluting the air.

[0049] like Figure 1 As shown, to further improve the accuracy of the experiment and avoid the influence of gases (such as air) in the artificial core 101 on the experiment, in this embodiment of the invention, the experimental apparatus further includes a vacuum structure 9. The vacuum structure 9 is used to connect at least one injection and sampling pipe 2 to evacuate the artificial core 101. Before injecting hydrogen sulfide-containing natural gas, the artificial core 101 is first evacuated by the vacuum structure 9, so that the subsequent artificial core 101 is only pressurized to a preset pressure by the injected hydrogen sulfide-containing natural gas.

[0050] like Figure 2 As shown, in embodiments of the present invention, the artificial core 101 comprises multiple core layers, which are stacked vertically, and each core layer has a different permeability and / or porosity. In some embodiments of the present invention, the permeability of the multiple core layers gradually decreases from bottom to top. For example, in one embodiment, there are two core layers, with the upper core layer 1011 having a permeability of 1 md and the lower core layer 1011' having a permeability of 10 md. The artificial core 101 has a height H1 of 20 cm, a length L1 of 1 m, and a width W1 of 1 m, wherein the height h of each core layer is 10 cm.

[0051] This invention uses an artificial core 101 to simulate a reservoir, enabling large-scale simulation and reducing experimental errors. The artificial core 101 is prepared based on similarity criteria. Firstly, it achieves geometric similarity, with the shape and size of the artificial core 101 resembling those of an actual gas storage reservoir. Secondly, it achieves physical property similarity by using multiple core layers stacked vertically with varying porosity and / or permeability to simulate reservoir heterogeneity. The artificial core 101 is prepared based on a pore structure with consistent permeability and porosity as seen in actual reservoirs.

[0052] Combination Figure 3 As shown, one end of each of the multiple hydrogen sulfide probes 402 can be pre-embedded in multiple detection areas 1012 of the artificial core 101 during the fabrication process. The number of detection areas 1012 is not specifically limited, and the artificial core 101 can be divided into multiple detection areas 1012 as needed.

[0053] In some embodiments of the present invention, the artificial core 101 formed by splicing core layers 1011' and 1011 has a height H1 of 20cm, a length L1 of 1m, and a width W1 of 1m. Each detection area 1012 has a height h of 10cm, a width W2 of 10cm, and a length L2 of 10cm, meaning each detection area 1012 is a cube with a side length of 10cm. Each core layer is divided into 100 detection areas 1012. Correspondingly, 100 hydrogen sulfide probes 402 are installed above the artificial core 101, embedded in the upper 100 detection areas 1012 and electrically connected to the first hydrogen sulfide detector 401. Similarly, 100 hydrogen sulfide probes 402 are installed below the artificial core 101, embedded in the lower 100 detection areas 1012 and electrically connected to the first hydrogen sulfide detector 401. Of course, the artificial core 101 can also be divided into detection areas of other quantities, sizes and / or shapes.

[0054] like Figure 4 As shown, the injection-production pipe 2 is used to simulate injection-production wells. During the fabrication of the artificial core 101, pre-reserved locations for the injection-production pipe 2 are established, i.e., pre-reserved well locations. These pre-reserved well locations are laid out according to the actual reservoir layout method, such as a quarter-well layout using the nine-point method, thus ensuring consistency with the injection-production method of a real gas storage facility. This further improves the realism and accuracy of simulating the hydrogen sulfide flushing process in a simulated gas reservoir. In this embodiment, multiple injection-production pipes 2 are used, distributed near the edge of the artificial core 101. These multiple injection-production pipes 2 simulate multiple injection-production wells to simulate different injection-production methods in a gas storage facility, such as simultaneous injection and production, single injection and production, or multiple injection and production. Furthermore, the gas injection structure simultaneously injects gas from multiple injection-production pipes 2 into the artificial core 101, improving efficiency and facilitating the filling of the artificial core 101 with gas to achieve a more ideal saturation state. Specifically, the injection-production pipe 2 can be a steel pipe. An injection-production control valve 202 is installed on the injection-production pipe 2. By setting the injection-production control valve 202, the gas injection and production pipe 2 is controlled to perform gas injection and production.

[0055] Combination Figure 1As shown, the sealing layer 102 is cast onto the artificial core 101 using a sealing material. Specifically, the sealing material includes, but is not limited to, epoxy resin. After the artificial core 101 is fabricated (one end of each of the multiple hydrogen sulfide probes 402 is pre-embedded in multiple detection areas 1012 of the artificial core 101 during its fabrication), the injection-production tube 2 is inserted into the pre-drilled holes in the artificial core 101. Then, the sealing material is cast onto the artificial core 101 to form the sealing layer 102. This ensures the airtightness between the artificial core 101 and the sealing layer 102, between the sealing layer 102 and the injection-production tube 2, and between the sealing layer 102 and the hydrogen sulfide probes 402, thus preventing hydrogen sulfide leakage from the artificial core 101 and improving the accuracy of the experimental structure. In addition, the injection-production tube 2 is equipped with a pressure monitoring structure 201 to monitor the injection pressure and production pressure during the gas injection-production process.

[0056] In some embodiments of the present invention, the artificial core 101 has a square planar shape, and four injection-production pipes 2 are distributed at the four corners of the artificial core 101. The insertion depth of the injection-production pipe 2, that is, the degree of perforation of the simulated injection-production well, is not specifically limited. For example, it can penetrate through the core layer 1011' and the core layer 1011 to simulate a fully perforated well; or it can only penetrate the upper core layer 1011 to simulate a partially perforated well.

[0057] like Figure 5 As shown, in some other embodiments of the present invention, the natural gas control valve 304 and the hydrogen sulfide-containing natural gas control valve 305 can be integrated into a multi-port control valve to achieve control of the injection of different gases.

[0058] like Figure 6 As shown, in some embodiments of the present invention, a second hydrogen sulfide detector 10 is also provided on the gas extraction pipeline 6. By providing the second hydrogen sulfide detector 10, the concentration of hydrogen sulfide can be monitored during the gas extraction process.

[0059] like Figure 7As shown, in some embodiments of the present invention, the experimental apparatus further includes a housing 11 and a third hydrogen sulfide detector 12. The three-dimensional artificial rock core model 1 is placed inside the housing 11, and the detection end of the third hydrogen sulfide detector 12 extends into the gap between the housing 11 and the three-dimensional artificial rock core model 1. By setting the housing 11 and the third hydrogen sulfide detector 12 to detect the concentration of hydrogen sulfide in the gap between the housing 11 and the three-dimensional artificial rock core model 1, it is possible to determine whether the gas in the artificial rock core 101 leaks from the sealing layer 102 into the gap between the housing 11 and the three-dimensional artificial rock core model 1. On the one hand, this facilitates monitoring whether the sealing layer 402 leaks, eliminating factors that could lead to inaccurate simulation results due to leakage of the sealing layer 102; on the other hand, it prevents gas from leaking into the environment, polluting the air, and also prevents safety accidents caused by gas leakage. Specifically, the housing 11 is made of a high-temperature and high-pressure resistant material, such as steel or titanium alloy. The wall thickness of the housing 11 is 5 cm, but it can be thicker to ensure that its sealing performance meets the requirements under high-temperature and high-pressure environments.

[0060] In addition, during actual use, an alarm can be added to the housing 11 of the present invention. The alarm is connected to the third hydrogen sulfide detector 12. When the third hydrogen sulfide detector 12 detects hydrogen sulfide gas in the housing 11, the alarm will sound, thereby prompting relevant personnel to inspect the three-dimensional artificial rock core model 1 and determine the cause of the fault.

[0061] The housing 11 can also be connected to the gas recovery structure 5 through the gas recovery pipeline 13. The gas recovery pipeline 13 is equipped with a recovery control valve. When gas leakage occurs in the three-dimensional artificial rock core model 1, the gas in the housing 11 can be discharged to the gas recovery structure 5 through the gas recovery pipeline 13 by opening the recovery control valve, and then centrally processed.

[0062] Implementation Method 2

[0063] like Figure 1 and Figure 3 As shown, the present invention also provides an experimental method for studying the hydrogen sulfide washing mechanism of sulfur-containing gas reservoirs, which can be implemented using the experimental apparatus in Embodiment 1.

[0064] The experimental method of the present invention includes the following steps:

[0065] Step S1: Check the sealing performance of the sealing layer 102 covering the artificial rock core 101 to ensure that the sealing performance of the sealing layer 102 meets the requirements.

[0066] Step S2: Vacuum the artificial rock core 101. Specifically, vacuum the artificial rock core 101 by activating the vacuuming structure 9.

[0067] Step S3: Inject hydrogen sulfide-containing natural gas into the artificial core 101 until the pressure in the artificial core 101 reaches the first preset pressure, then stop injecting the hydrogen sulfide-containing natural gas. Specifically, open the hydrogen sulfide-containing natural gas control valve 305, start the injection pump 303, and inject the hydrogen sulfide-containing natural gas from the hydrogen sulfide-containing natural gas pipeline 302 into the artificial core 101 from the injection-production pipe 2 until the pressure in the artificial core 101 reaches the first preset pressure, then close the hydrogen sulfide-containing natural gas control valve 305 and the injection pump 303 to stop injecting the hydrogen sulfide-containing natural gas.

[0068] Step S4: Place the artificial rock core 101 for a preset time until the internal pressure of the artificial rock core 101 reaches equilibrium. Specifically, when the pressure displayed by the pressure monitoring structure 201 shows no change or a very small change, it indicates that the internal pressure of the artificial rock core 101 has reached equilibrium.

[0069] Step S5: Record the hydrogen sulfide concentration in each detection area 1012 of the artificial core 101. Specifically, the first hydrogen sulfide detector 404 processes and analyzes the detection signals collected by multiple hydrogen sulfide probes 402 to generate the hydrogen sulfide concentration and uploads it to the processing terminal 403 for recording.

[0070] Step S6: Inject natural gas into the artificial core 101 until the pressure in the artificial core 101 reaches the second preset pressure, then stop the injection and monitor the change in hydrogen sulfide concentration in each detection area 1012 over time. Specifically, open the natural gas control valve 304, start the injection pump 303, and inject the hydrogen sulfide-containing natural gas from the natural gas pipeline 301 into the artificial core 101 from the injection-production pipe 2 until the pressure in the artificial core 101 reaches the second preset pressure. Then, close the natural gas control valve 304 and the injection pump 303 to stop the injection of natural gas.

[0071] Step S7: When the concentration of hydrogen sulfide in each detection area 1012 no longer changes, gas extraction is carried out. During the gas extraction process, the change in the concentration of hydrogen sulfide in each detection area 1012 is monitored in real time. Specifically, the gas extraction control valve 7 is opened, the extraction pump 8 is started, and the gas in the artificial core 101 is extracted from the injection-production pipe 2 and recovered to the gas recovery structure 5 through the gas extraction pipeline 6.

[0072] Step S8: Repeat steps S6 and S7, and monitor the changes in hydrogen sulfide concentration in each detection area 1012 in real time. Specifically, the first hydrogen sulfide detector 404 processes and analyzes the detection signals collected by multiple hydrogen sulfide probes 402 to generate the hydrogen sulfide concentration and uploads it to the processing terminal 403 for recording.

[0073] Step S9: Interpolate the recorded hydrogen sulfide concentrations of each detection area 1012 and assign different colors to different hydrogen sulfide concentrations to obtain a hydrogen sulfide distribution map of the artificial core 101. Specifically, the processing terminal 403 interpolates the recorded hydrogen sulfide concentrations of each detection area 1012 and assigns different colors to different hydrogen sulfide concentrations to obtain a hydrogen sulfide distribution map of the artificial core 101.

[0074] In step S3, hydrogen sulfide-containing natural gas is injected into the artificial core 101 to a first preset pressure to simulate a depleted gas reservoir containing hydrogen sulfide before reservoir construction. Since the pressure of a depleted gas reservoir is inherently low, in this embodiment, the upper pressure resistance of the sealing layer 102 is approximately 5 MPa, and the first preset pressure is set to 2 MPa to reflect the characteristics of a real gas reservoir. In step S6, natural gas is injected into the artificial core 101 to a second preset pressure to simulate the diffusion of natural gas into a depleted gas reservoir containing hydrogen sulfide to wash away the hydrogen sulfide. Setting the second preset pressure to 3 MPa meets the experimental requirements, allowing observation of the hydrogen sulfide diffusion and washing process, while also ensuring experimental safety and reducing the safety hazards caused by hydrogen sulfide leakage due to excessive pressure.

[0075] The process involves repeating steps S6 and S7 to simulate the actual production process of a gas storage facility, with injection and extraction occurring in cycles. Numerical simulation studies predict that the hydrogen sulfide concentration will increase from 20 g / m³ to approximately 20 g / m³ after about ten cycles. 3 It can be reduced to 1.5g / m 3 After approximately fifteen cycles of hydrogen sulfide washing, the concentration of hydrogen sulfide becomes very stable. The injection-production cycle can be adjusted based on the experimental results, i.e., the number of repetitions of steps S6 and S7. When the concentration of hydrogen sulfide is already very low and does not change significantly with each injection-production cycle, the washing process can be stopped, and the experimental results obtained. In some embodiments of the present invention, the number of repetitions of steps S6 and S7 is set to four to seven times, which can wash until the hydrogen sulfide concentration is below 1 mg / m³. 3 In some other embodiments of the invention, steps S6 and S7 may be repeated until the hydrogen sulfide concentration is lower than the concentration required for the study, for example, 2 mg / m³. 3 1.5mg / m 3 0.8 mg / m 3 etc., without specific limitations.

[0076] The above descriptions are merely a few embodiments of the present invention. Those skilled in the art can make various modifications or variations to the embodiments of the present invention based on the content disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. An experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs, characterized in that, An experimental apparatus for studying the hydrogen sulfide washing mechanism of sulfur-bearing gas reservoirs is employed. The apparatus includes: a three-dimensional artificial core model, comprising a sealing layer and an artificial core, the sealing layer covering the artificial core; a hydrogen sulfide detection mechanism, including a first hydrogen sulfide detector and multiple hydrogen sulfide probes, one end of which penetrates the sealing layer and extends into multiple detection areas within the artificial core, the other end of which is electrically connected to the first hydrogen sulfide detector; at least one injection-production pipe, one end of which penetrates the sealing layer and extends into the artificial core; a gas injection mechanism connected to the other end of the injection-production pipe; and a gas recovery structure connected to the injection-production pipe via a gas production pipeline, the gas production pipeline being equipped with a gas production control valve, a production pump, and a second hydrogen sulfide detector. The experimental method includes the following steps: S3. Inject hydrogen sulfide-containing natural gas into the artificial rock core until the pressure in the artificial rock core reaches the first preset pressure, then stop injecting hydrogen sulfide-containing natural gas. S4. Place the artificial rock core for a preset time until the internal pressure of the artificial rock core reaches equilibrium. S5. Record the concentration of hydrogen sulfide in each detection area of ​​the artificial rock core. S6. Inject natural gas into the artificial rock core until the pressure in the artificial rock core reaches the second preset pressure, and stop the injection. Monitor the change of hydrogen sulfide concentration in each detection area over time in real time. S7. Gas sampling is performed when the concentration of hydrogen sulfide in each of the detection areas no longer changes. During the gas sampling process, the change in the concentration of hydrogen sulfide in each of the detection areas is also monitored in real time. S8. Repeat steps S6 and S7, and monitor the changes in hydrogen sulfide concentration in each detection area in real time.

2. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, Before step S3, the following steps are also included: S1. Inspect the sealing performance of the sealing layer covering the artificial rock core to ensure that the sealing performance of the sealing layer meets the requirements; S2. Vacuum the artificial rock core.

3. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, The first preset pressure is 2 MPa; the second preset pressure is 3 MPa.

4. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, Repeat steps S6 and S7 until the hydrogen sulfide concentration is below 1 mg / m³. 3 Or the concentration of hydrogen sulfide required for the study.

5. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, After step S8, the method further includes the following steps: S9, interpolating the recorded hydrogen sulfide concentrations of each detection area and assigning different colors to different hydrogen sulfide concentrations to obtain a hydrogen sulfide distribution map of the artificial core.

6. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, The artificial core comprises multiple core layers, which are stacked and spliced ​​together in a vertical direction, and each core layer has a different permeability and / or porosity.

7. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, The sealing layer is cast onto the artificial rock core using a sealing material.

8. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, The number of injection and production pipes is multiple, and the multiple injection and production pipes are distributed near the edge of the artificial rock core.

9. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, The injection-production pipe is equipped with an injection-production control valve and a pressure monitoring structure.

10. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, The hydrogen sulfide detection mechanism further includes a processing terminal, which is electrically connected to the first hydrogen sulfide detector. The processing terminal is used to analyze and process the detection signal from the first hydrogen sulfide detector to generate a hydrogen sulfide distribution map of the artificial rock core.

11. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, The gas injection mechanism includes a natural gas pipeline, a hydrogen sulfide-containing natural gas pipeline, and an injection pump. The natural gas pipeline connects the injection-production pipe to the natural gas supply structure, and the hydrogen sulfide-containing natural gas pipeline connects the injection-production pipe to the hydrogen sulfide-containing natural gas supply structure. The injection pump is used to provide transportation power for the natural gas to be transported from the natural gas pipeline to the injection-production pipe and / or for the hydrogen sulfide to be transported from the hydrogen sulfide-containing natural gas pipeline to the injection-production pipe.

12. The experimental method for studying the hydrogen sulfide washing mechanism of sulfur-bearing gas reservoirs according to claim 11, characterized in that, The natural gas pipeline is equipped with a natural gas control valve, and the hydrogen sulfide-containing natural gas pipeline is equipped with a hydrogen sulfide-containing natural gas control valve.

13. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, The experimental apparatus also includes a vacuuming structure for connecting at least one of the injection-production pipes to evacuate the artificial core.

14. The experimental method for studying the hydrogen sulfide washing mechanism in sulfur-bearing gas reservoirs according to claim 1, characterized in that, The experimental apparatus also includes a housing and a third hydrogen sulfide detector. The three-dimensional artificial rock core model is placed inside the housing, and the detection end of the third hydrogen sulfide detector extends into the gap between the housing and the three-dimensional artificial rock core model.

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