A method and device for evaluating the extraction capacity of water-soluble helium from a natural gas layer

Abstract

The present invention provides a method and device for evaluating the extraction capacity of water-soluble helium from a natural gas layer. This method, which belongs to the field of oil and gas resource evaluation technology, addresses the existing problems of being unable to simulate the extraction of helium from natural gas under real geological conditions and the inability to quantitatively evaluate the extraction capacity. The method comprises a natural gas preparation area, a helium solution preparation area, a blending box, and a test cylinder. The blending box is provided with at least two blending tanks, one of which is connected to the natural gas preparation area and the other to the helium solution preparation area. The test cylinder is provided with a piston having an inlet and an outlet. The outlet is connected to a gas composition detection device, and the piston is connected to a pressing device. The present invention is used to study the mechanism by which groundwater-soluble helium resources enter natural gas layers. It can simulate the extraction process of natural gas from water-soluble helium under different temperature, pressure, and salinity conditions in natural gas layers and quantitatively evaluate the extraction capacity of natural gas for water-soluble helium.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas resource evaluation, and in particular to a method and device for evaluating the extraction capacity of a natural gas layer for water-soluble helium. Background Art

[0002] As a non-renewable resource, helium plays an irreplaceable role in the fields of national defense and high-tech due to its unique physical properties. However, the current global annual helium production (about 17×10 8 m 3 ) is less than the demand (about 22×10 8 m 3 With the rapid development of high-tech, the gap between supply and demand is widening year by year, and the price of helium has soared more than fourfold in recent years.

[0003] In recent years, research has suggested that the solubility of helium in formation water is governed by Henry's law, increasing with increasing temperature and pressure and decreasing with increasing salinity. Based on Henry's law, some studies have estimated the solubility of helium in ideal conditions, such as pure water. Experimental simulations of helium solubility in pure water at 0–100 MPa and 5–80°C have revealed that under formation temperature and pressure conditions, the solubility of helium is enormous. The solubility capacity of formation water within shale formations exceeds the accumulated helium production by 4–5 orders of magnitude, and helium primarily exists in dissolved form in formation water. According to Henry's law, at the gas-water interface between the aqueous helium solution and the gas layer, the helium partial pressure on the natural gas side is extremely low. As the helium partial pressure drops dramatically from the aqueous solution to the gas layer, helium gradually enters the natural gas layer from its dissolved state, causing the dissolved helium to be "extracted" by the natural gas, transforming it from dissolved to free within the gas layer. Current research, however, primarily relies on single-factor simulations of temperature or pressure under pure water conditions. This approach fails to simulate the extraction of helium from natural gas at the gas-water interface under realistic geological conditions, including natural gas composition, formation temperature, pressure, and salinity. Furthermore, in practice, the relationship between helium-rich reservoirs and the presence of bottom water is unclear. Furthermore, the intensity and rate of natural gas extraction at the gas-water interface above helium-unsaturated formation water remain elusive, directly hindering understanding of the formation mechanism of helium-rich natural gas and the development of exploration technologies. Therefore, a method and device are needed to assess the extraction capacity of natural gas layers at the gas-water interface for dissolved helium, under conditions that closely simulate geological conditions. Summary of the Invention

[0004] In response to the above problems, the purpose of the present invention is to provide a method and device for evaluating the extraction capacity of natural gas layers for water-soluble helium, which is used to study the mechanism by which underground water-soluble helium resources enter natural gas layers. The present invention can simulate the process of natural gas extraction of water-soluble helium resources under different temperature, pressure and salinity conditions in natural gas layers, and determine the contribution of natural gas extraction of water-soluble helium to helium enrichment in the gas layer.

[0005] The technical solution adopted in the present invention is as follows:

[0006] A device for evaluating the extraction capacity of water-soluble helium from a natural gas layer comprises a natural gas preparation area, a helium solution preparation area, a blending box, and a test cylinder. The blending box is provided with at least two blending tanks, one of which is connected to the natural gas preparation area, and the other is connected to the helium solution preparation area. A piston is provided in a movable seal in the test cylinder. The piston is provided with an air inlet and an air outlet that communicate with the inner side of the piston. The air inlet is connected to the bottom of the blending tank via a pipeline, and the air outlet is connected to a gas component detection device via a pipeline. The piston is connected to a pressing device.

[0007] Preferably, the bottom of the test cylinder is connected to a gas-liquid separator through a pipeline, a first flow meter is provided on the pipeline connecting the test cylinder and the gas-liquid separator, and the bottom and top of the gas-liquid separator are connected to the gas component detection equipment through pipelines.

[0008] Preferably, the outer side of the test cylinder is provided with a protective cylinder, the mixing box and the protective cylinder are filled with liquid heat-conducting medium, the mixing box and the protective cylinder are provided with heating pipes, and the mixing box and the protective cylinder are provided with thermometers for monitoring the temperature of the liquid heat-conducting medium.

[0009] Preferably, a heat-insulating layer is provided on the outside of the mixing box and the protective cylinder.

[0010] Preferably, an exhaust pipe is provided on the top of the mixing tank.

[0011] Preferably, a first pressure gauge is connected to the top of the mixing tank.

[0012] Preferably, a second pressure gauge and a second flow meter are provided on the pipeline connected to the air outlet.

[0013] Preferably, an observation window is provided on the top of the mixing box, and transparent glass is provided on the top of the mixing tank.

[0014] Preferably, the natural gas configuration area includes several gas tanks, the helium solution configuration area includes a helium tank and a simulated water tank, the helium solution configuration area is provided with three groups and is used to configure the helium and simulated water required for low, medium and high concentration helium solutions, and four mixing tanks are provided.

[0015] A method for evaluating the extraction capacity of water-soluble helium from a natural gas layer, using the evaluation device, the evaluation method comprising:

[0016] Inject the various gas components of natural gas into the vacuumed gas tank according to volume, and transport each gas to one of the vacuumed blending tanks in turn;

[0017] Based on the temperature and pressure variations of the solubility of helium in pure water, the upper limit of helium solubility in formation water was estimated. The historical helium generation of the deep potential helium source rock was estimated based on the historical helium generation calculation formula, combined with the tectonic position of the formation. The dissolved helium concentration in the formation water was estimated based on the rock porosity and water content. This was used as the low concentration of the helium solution. Based on the volume of the blending tank, corresponding amounts of helium and simulated water with a simulated formation water salinity were injected into the helium tank and simulated water tank, respectively. The simulated water was first injected into the blending tank, followed by helium to obtain a low-concentration helium solution. Based on the low-concentration helium solution, the amount of helium required for the medium-concentration helium solution was calculated based on the helium abundance in the natural gas layer and the amount of natural gas in the blending tank. The helium was then injected into another set of helium tanks in the helium solution preparation area, and the simulated water and helium were then injected into another blending tank. The high-concentration helium solution, taking into account the loss of helium over geological history, was prepared at a concentration twice that of the medium-concentration helium solution. The simulated water and helium were then injected into the remaining blending tank.

[0018] After all the blending tanks are filled with the corresponding liquids and gases, the heating pipes of the blending boxes are turned on and the temperature of the blending boxes is raised to the formation temperature through a water bath. When the helium in the blending tanks is completely dissolved, the ability of natural gas to extract water-soluble helium is tested.

[0019] Before the test, the chamber under the piston is evacuated, the piston is preheated to the simulated temperature through the heating tube, and then high, medium and low concentration helium solutions are injected into the chamber in sequence, and finally natural gas is added; the second pressure gauge monitors the pressure changes in the chamber, and then controls the pressing force of the pressing device on the piston to keep the pressure in the chamber stable at the set simulated pressure value during the entire gas injection process. After it is left to stand for the designed sampling time, the collected gas sample is transported to the gas composition detection equipment through the pipeline connected to the gas outlet, and the volume of the gas under the formation temperature and pressure state is recorded by the second flow meter; after the gas composition detection equipment obtains the extracted helium The amount of helium in the natural gas layer is then used to calculate the proportion of dissolved helium extracted. Simultaneously, helium solution is discharged from the bottom of the test cylinder, and the volume of the helium solution is measured by a first flowmeter. The discharged helium solution enters a gas-liquid separator. A gas component detection device measures the helium concentration in the gas separated by the gas-liquid separator and in the helium solution to estimate the helium concentration in the helium solution in the test cylinder. The amount of dissolved helium in the test cylinder and the amount of free helium in the gas layer are compared with the total amount of helium input to evaluate the amount of helium solution extracted by natural gas at different times, thereby determining the intensity of the natural gas extraction effect on helium and the changing pattern of its extraction rate.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0021] The present invention is used to study the mechanism by which underground water-soluble helium resources enter natural gas formations. The present invention can simulate the extraction process of water-soluble helium resources by natural gas in natural gas formations under different temperature, pressure and salinity conditions, and determine the contribution of the extraction of water-soluble helium by natural gas to helium enrichment in the formation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of a process flow provided by an embodiment of the present invention.

[0024] Figure 1: 1-natural gas configuration area; 101-gas tank; 2-helium solution configuration area; 201-helium tank; 202-simulated water tank; 3-compressor; 4-blending box; 5-observation window; 6-exhaust pipe; 7-first pressure gauge; 8-thermometer; 9-blending tank; 10-heating tube; 11-first flow meter; 12-stress pad; 13-second pressure gauge; 14-piston; 15-gas-liquid separator; 16-second flow meter; 17-test cylinder; 18-protective cylinder; 19-support frame; 20-air inlet; 21-air outlet; 22-gas component detection equipment. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the application is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0028] The following combination Figure 1 The present invention is described in detail. Example

[0029] A device for evaluating the extraction capacity of water-soluble helium from a natural gas layer, such as Figure 1As shown, it includes a natural gas preparation area 1, a helium solution preparation area 2, a blending box 4 and a test cylinder 17. The blending box 4 is provided with at least two blending tanks 9, one of which is connected to the natural gas preparation area 1, and the other blending tank 9 is connected to the helium solution preparation area 2. A piston 14 is provided in a movable seal in the test cylinder 17. The piston 14 is provided with an air inlet 20 and an air outlet 21 connected to the inner side of the piston 14. The air inlet 20 is connected to the bottom of the blending tank 9 through a pipeline, and the air outlet 21 is connected to a gas component detection device 22 through a pipeline. The piston 14 is connected to a pressing device.

[0030] The natural gas configuration area 1 includes several gas tanks 101, the number of which is equal to the number of gas types in the natural gas. The natural gas configuration area 1 feeds relevant gases into the gas tanks 101 based on the actual gas types. The number of times each gas tank 101 is charged with its corresponding gas is determined based on the gas components and the water saturation of the formation water. Each gas is then fed into one of the blending tanks 9 for mixing. The helium solution configuration area 2 includes a helium tank 201 and a simulated water tank 202. A fixed amount of helium is fed into the helium tank 201, and a fixed amount of simulated water is fed into the simulated water tank 202 to produce the simulated water and helium required for a helium solution of a certain concentration. Three groups of helium solution configuration areas 2 are provided to simulate high, medium, and low helium solution concentrations, respectively, based on the helium concentration in the formation water calculated from the cumulative helium production in the formation. Four blending tanks 9 are provided, one of which is filled with natural gas, and the others are filled with helium solutions of low, medium, and high concentrations, respectively.

[0031] The prepared helium solution and natural gas are transported to the chamber below piston 14 for testing. The pressure applied by a pressing mechanism (which can be a hydraulic telescopic rod, not shown) on piston 14 varies with chamber pressure, maintaining a stable pressure. When sampling time arrives, the pipeline connected to the chamber's gas outlet 21 is opened, allowing the gas to enter gas composition detection equipment 22 for testing. The amount of helium in the natural gas layer after helium extraction is determined, allowing the proportion of extracted dissolved helium to be calculated. Gas composition detection equipment 22 can be replaced with a steel cylinder, which can then be sent to a reputable testing agency for testing.

[0032] The bottom of the test cylinder 17 is connected to the gas-liquid separator 15 via a pipe. A first flowmeter 11 is installed on the pipe connecting the test cylinder 17 and the gas-liquid separator 15. Both the bottom and top of the gas-liquid separator 15 are connected to a gas composition detection device 22 via pipes. Helium solution is discharged from the bottom of the test cylinder 17, and its volume is measured by the first flowmeter 11. The discharged helium solution then enters the gas-liquid separator 15. The gas composition detection device 22 measures the helium concentration in the gas separated by the gas-liquid separator 15 and in the helium solution, estimating the helium concentration in the helium solution in the test cylinder 17. The amount of dissolved helium and free helium in the gas layer in the test cylinder 17 is compared with the total amount of helium input to evaluate the amount of helium solution extracted by natural gas at different times. This allows the intensity of the natural gas extraction of helium and the variation of its extraction rate to be determined, thereby helping to reveal the mechanism of helium enrichment in natural gas. By knowing the helium content in the natural gas and the helium content in the water discharged from the bottom of the test cylinder 17, the intensity and rate of the extraction effect of the natural gas on the dissolved helium can be quantitatively identified.

[0033] A protective cylinder 18 is sheathed around the outer surface of the test cylinder 17. The mixing tank 4 and protective cylinder 18 are filled with a liquid heat-conducting medium (water or oil). A heating pipe 10 is installed within the mixing tank 4 and protective cylinder 18. The mixing tank 4 and protective cylinder 18 are also equipped with a thermometer 8 for monitoring the temperature of the liquid heat-conducting medium. Heat generated by the heating pipe 10 is transferred to the mixing tank 9 and test cylinder 17 via the liquid heat-conducting medium, simulating actual formation temperature. The temperature displayed by the thermometer 8 changes, allowing the heating pipe 10 to be turned on and off to maintain temperature stability.

[0034] The outside of the mixing box 4 and the protective cylinder 18 is provided with a heat-insulating layer. The heat-insulating layer can reduce the temperature loss of the mixing box 4 and the protective cylinder 18, thereby reducing the opening and closing frequency of the heating pipe 10.

[0035] The top of the mixing tank 9 is provided with an exhaust pipe 6. A valve is provided on the exhaust pipe 6 to discharge the residual gas therein before the experiment to avoid the residual gas affecting the test.

[0036] The top of the blending tank 9 is connected to a first pressure gauge 7 to check whether the pressure in the blending tank 9 is close to the pressure of the formation.

[0037] The pipeline connected to the gas outlet 21 is equipped with a second pressure gauge 13 and a second flow meter 16. The second pressure gauge 13 monitors the pressure in the chamber below the piston 14, thereby adjusting the pressing force of the pressing device accordingly. The second flow meter 16 records the volume of gas delivered to the gas composition detection device 22 under the formation temperature and pressure conditions.

[0038] An observation window 5 is provided on the top of the mixing box 4, and a transparent glass is provided on the top of the mixing tank 9. Through the observation window 5 and the transparent glass, the situation in the mixing tank 9 can be observed, so as to know whether the helium in the mixing tank 9 is completely dissolved, thereby minimizing heat loss. If it does not dissolve quickly, it needs to be left to stand for a period of time until the helium is completely dissolved before the test operation can be carried out. Among them, the transparent glass is tempered glass, which can ensure that the structural strength of the mixing tank 9 meets the pressurization requirements. The transparent glass can also be set on the exhaust pipe 6.

[0039] The helium tank 201, simulated water tank 202, and each gas tank 101 are each connected to an output pipe equipped with a valve to control the gas or liquid output from each tank. The output pipes of all gas tanks 101 are combined into a main pipe, which is then connected to the bottom of the blending tank 9. This main pipe is equipped with a compressor 3 and a valve located between the compressor 3 and the blending tank 9. The output pipes of each group of helium tanks 201 and simulated water tanks 202 are combined into a main pipe, which is then connected to the bottom of the blending tank 9. This main pipe is also equipped with a compressor 3 and a valve located between the compressor 3 and the blending tank 9. The compressor 3 pressurizes the corresponding gas or liquid and delivers it to the blending tank 9, increasing the pressure in the blending tank 9.

[0040] The bottom of the mixing tank 9 is connected to a branch discharge pipe. Each branch discharge pipe is equipped with a valve to control the discharge of gas or liquid from each mixing tank 9. All branch discharge pipes converge into a main discharge pipe that communicates with the air inlet 20. The main discharge pipe is equipped with a compressor 3 to pressurize and deliver liquid to the chamber below the piston 14. When adjusting the chamber pressure, the speed of the compressor 3 can also be adjusted, and it can be used in conjunction with the pressing device. The main discharge pipe can be a soft tube or a rigid tube. If a soft tube is used, it is fixed to the piston 14 and can move with the piston 14. If a rigid tube is used, it is movably sealed and inserted into the air inlet 20 and the air outlet 21.

[0041] A valve is provided on the pipe connected to the air outlet 21, which is located between the second pressure gauge 13 and the gas component detection equipment 22, and the second flow meter 16 is located between the second pressure gauge 13 and the valve; valves are provided on the pipes connecting the bottom of the test cylinder 17 and the bottom of the gas-liquid separator 15.

[0042] The compressor 3 is a dual-purpose gas-liquid booster; the valve is used to control the opening and closing of the corresponding pipeline, thereby realizing the transportation and storage of gas or liquid.

[0043] The piston 14 is cast from an alloy with high strength and good thermal conductivity, capable of withstanding temperature and pressure conditions simulating the temperature and pressure state of the formation. The outer wall of the piston 14 is provided with multiple layers of airtight rings to ensure the airtightness between the piston 14 and the test cylinder 17. The piston 14 is provided with a stress pad 12 cast from an alloy. The stress pad 12 is strong and, when in contact with the pressing device, can disperse the mechanical pressure of the pressing device above on the piston 14 and slow down heat loss. A support frame 19 is provided between the test cylinder 17 and the protective cylinder 18 to enhance the structural strength of the test cylinder 17. The support frame 19 is hollowed out to facilitate uniform heating of the heating fluid therein.

[0044] A method for evaluating the extraction capacity of water-soluble helium from a natural gas layer, using an evaluation device, and comprising:

[0045] Based on the identification results of the components of the helium-containing natural gas, the simulated formation temperature and pressure, and the volume of the blending tank 9, the total volume of the simulated gas and the gas volumes of the main gas components are calculated according to the ideal gas state equation (see Formula 1);

[0046] pV=nRT (1)

[0047] Where p is the pressure (Pa), V is the gas volume (m³), T is the temperature (K), n is the amount of gas (mol), and R is the molar gas constant (J / (mol·K)).

[0048] Inject the various gas components of natural gas into the evacuated gas tank 101 according to volume, and deliver each gas to one of the evacuated blending tanks 9 in sequence. After delivery, keep the blending tank 9 in a closed state;

[0049] According to the variation of the solubility of helium in pure water with temperature and pressure (see Table 1), the upper limit of the solubility of helium in formation water is estimated. Then, based on the structural position of the formation, the historical helium generation of the deep possible helium source rock is estimated according to the historical helium generation calculation formula (see Formula 2-4). The dissolved helium concentration in the formation water is estimated based on the rock porosity and water content. This is used as the low concentration value of the helium solution. Based on the volume of the mixing tank 9, the corresponding amount of helium and simulated water with simulated formation water salinity are injected into the helium tank 201 and the simulated water tank 202 respectively. First, the simulated water is filled with water. The simulated water is injected into the blending tank 9, and then helium is injected to obtain a low-concentration helium solution. Based on the low-concentration helium solution, the amount of helium required for the medium-concentration helium solution is calculated in combination with the helium abundance in the natural gas layer and the amount of natural gas in the blending tank 9. The helium is injected into the helium tank 201 of another group of helium solution configuration areas 2, and the simulated water and helium are then injected into another blending tank 9. The high-concentration helium solution is prepared by taking into account the loss of helium over geological history and has a concentration twice that of the medium-concentration helium solution. The simulated water and helium are then injected into the remaining blending tank 9.

[0050] r n He =1.21×10 -13 ×U+2.89×10 -14 ×Th (2)

[0051] r n He The rock generation per ton per year for the nth formation 4 The amount of He, in m 3 / t·a; U is the average abundance of uranium in the nth set of strata, in ppm; Th is the average abundance of thorium in the nth set of sedimentary strata, in ppm;

[0052] Q n He = r n He × v n rock × r n s × T n rock (3)

[0053] Q n He For the nth formation 4 The historical cumulative helium production of He, in m 3 ; r n He The rock generation per ton per year for the nth formation 4 The amount of He, in m 3 / t·a; v n rock is the volume of the nth formation, in m 3 ; r n s is the density of the nth set of stratum rocks, in t / m 3 ; T n rock is the helium generation time of the nth formation, in units of a;

[0054] The large-scale release of helium generated by helium-producing elements in helium-containing minerals needs to be higher than their closing temperature. There are obvious differences in the closing temperatures of different helium-containing minerals. For example, the closing temperatures of apatite, hematite, zircon, garnet, monazite, titanite, and uraninite are 55-100℃, 90-250℃, 180-200℃, 590-630℃, 182-299℃, 150-200℃, and ~200℃, respectively. T n rock The value of can be referred to the thermal history curve of the drilling well to make an approximate estimate of the time to reach its sealing temperature. U and Th in shale are mainly in adsorption or complex state, and there is no sealing temperature of helium. The shale age can be used as an approximate value. T n rock value;

[0055] Q He = Q 1 He + Q 2 He …+ Q i He …+ Q n He (4)

[0056] Q He is the historical cumulative helium production, in m 3 ; Q 1 He For the first set of strata 4 The historical cumulative helium production of He, in m 3 ; Q i He is the i-th formation 4 The historical cumulative helium production of He, in m 3 ; Q n He For the nth formation 4 The historical cumulative helium production of He, in m 3 ;

[0057] After all the blending tanks 9 are filled with the corresponding liquids and gases, the heating pipe 10 of the blending box 4 is turned on, and the temperature of the blending box 4 is raised to the formation temperature by heating in a water bath. When the helium in the blending tank 9 is completely dissolved, the ability of natural gas to extract water-soluble helium is tested;

[0058] Before the test, the chamber below the piston 14 is evacuated, the temperature of the piston 14 is preheated to the simulated temperature through the heating tube 10, and then high, medium and low concentration helium solutions are injected into the chamber in sequence, and finally natural gas is added; the second pressure gauge 13 monitors the pressure change in the chamber, and then controls the pressing force of the pressing device on the piston 14 to keep the pressure in the chamber stable at the set simulated pressure value during the entire gas injection process. After it is left to stand for the designed sampling time, the collected gas sample is transported to the gas composition detection device 22 (the gas composition detection device 22 is the existing technology) through the pipeline connected to the gas outlet 21, and the volume of the gas under the formation temperature and pressure conditions is recorded by the second flowmeter 16; the gas composition detection The device 22 obtains the amount of helium in the natural gas layer after helium extraction, and then calculates the proportion of extracted dissolved helium. Simultaneously, a helium solution is discharged from the bottom of the test cylinder 17, and the volume of the helium solution is measured by the first flowmeter 11. The discharged helium solution enters the gas-liquid separator 15. The gas component detection device 22 measures the helium concentration in the gas separated by the gas-liquid separator 15 and in the helium solution, estimating the helium concentration in the helium solution in the test cylinder 17. The amount of dissolved helium in the test cylinder 17 and the amount of free helium in the gas layer are compared with the total amount of helium input. The amount of helium solution extracted by the natural gas at different times is evaluated, and the intensity of the natural gas extraction of helium and the variation pattern of its extraction rate are determined.

[0059] Table 1 Helium solubility in pure water as a function of temperature and pressure (ml / kg)

[0060]

[0061] This invention enables comprehensive simulation of complex geological conditions such as formation temperature, pressure, salinity, and water content in a laboratory setting. It can set sampling intervals at arbitrary intervals to quantitatively assess the extraction capacity and rate of water-soluble helium from natural gas. This overcomes previous experimental and research results based solely on idealized conditions based on Henry's law or single-factor simulations, which resulted in an inability to quantitatively assess the extraction capacity of natural gas for water-soluble helium and its contribution to the formation of helium within natural gas formations. This invention reveals the mechanism of helium enrichment in natural gas, directly contributing to the prediction of favorable helium-rich natural gas zones.

[0062] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A device for evaluating the extraction capacity of water-soluble helium from a natural gas layer, characterized in that: The invention comprises a natural gas configuration area (1), a helium solution configuration area (2), a blending box (4) and a test cylinder (17), wherein the blending box (4) is provided with at least two blending tanks (9), wherein one blending tank (9) is communicated with the natural gas configuration area (1), and the other blending tank (9) is communicated with the helium solution configuration area (2), and a piston (14) is provided in a movable seal in the test cylinder (17), wherein the piston (14) is provided with an air inlet (20) and an air outlet (21) which are communicated with the inner side of the piston (14), and the air inlet (20) is connected to the blending box (4) through a pipeline. The bottom of the mixing tank (9) is connected, the gas outlet (21) is connected to the gas component detection device (22) through a pipeline, and the piston (14) is connected to the pressing device; the outer side of the test cylinder (17) is provided with a protective cylinder (18), the mixing box (4) and the protective cylinder (18) are filled with liquid heat conducting medium, and the mixing box (4) and the protective cylinder (18) are provided with a heating pipe (10), the natural gas configuration area (1) includes several gas tanks (101), and the helium solution configuration area (2) includes a helium tank (201) and a simulated water tank (202).

2. The device for evaluating the extraction capacity of water-soluble helium from a natural gas layer according to claim 1, characterized in that: The bottom of the test cylinder (17) is connected to the gas-liquid separator (15) via a pipeline, a first flow meter (11) is provided on the pipeline connecting the test cylinder (17) and the gas-liquid separator (15), and the bottom and top of the gas-liquid separator (15) are both connected to the gas component detection device (22) via pipelines.

3. The device for evaluating the extraction capacity of water-soluble helium from a natural gas layer according to claim 1, characterized in that: The mixing box (4) and the protective cylinder (18) are provided with a thermometer (8) for monitoring the temperature of the liquid heat-conducting medium.

4. The device for evaluating the extraction capacity of water-soluble helium from a natural gas layer according to claim 3, characterized in that: The outer sides of the mixing box (4) and the protective cylinder (18) are provided with a heat-insulating layer.

5. The device for evaluating the extraction capacity of water-soluble helium from a natural gas layer according to claim 1, characterized in that: An exhaust pipe (6) is provided on the top of the mixing tank (9).

6. The device for evaluating the extraction capacity of water-soluble helium from a natural gas layer according to claim 1, characterized in that: The top of the mixing tank (9) is connected to a first pressure gauge (7).

7. The device for evaluating the extraction capacity of water-soluble helium from a natural gas layer according to claim 2, characterized in that: A second pressure gauge (13) and a second flow meter (16) are provided on the pipeline connected to the air outlet (21).

8. The device for evaluating the extraction capacity of water-soluble helium from a natural gas layer according to claim 1, characterized in that: The top of the mixing box (4) is provided with an observation window (5), and the top of the mixing tank (9) is provided with transparent glass.

9. The device for evaluating the extraction capacity of water-soluble helium from a natural gas layer according to claim 1, wherein: The helium solution configuration area (2) is provided with three groups and is used to configure helium gas and simulated water required for configuring three types of helium solutions with low, medium and high concentrations, and four mixing tanks (9) are provided.

10. A method for evaluating the extraction capacity of water-soluble helium from a natural gas layer, characterized in that: Using the evaluation device according to claim 7, the evaluation method includes: Injecting various gas components of natural gas into a vacuumed gas tank (101) by volume, and sequentially conveying each gas into one of the vacuumed blending tanks (9); According to the variation of the solubility of helium in pure water with temperature and pressure, the upper limit of the solubility of helium in formation water is estimated. Then, based on the structural position of the formation, the historical helium generation of the deep possible helium source rock is estimated according to the calculation formula of historical helium generation. The concentration of dissolved helium in formation water is estimated based on the porosity and water content of the rock. It is used as the low concentration value of the helium solution. Based on the volume of the mixing tank (9), the corresponding amount of helium and simulated water with simulated formation water salinity are injected into the helium tank (201) and the simulated water tank (202) respectively. The simulated water is first injected into the mixing tank (9). ), and then inject helium to obtain a low-concentration helium solution; on the basis of the low-concentration helium solution, combined with the helium abundance in the natural gas layer and the amount of natural gas in the blending tank (9), the amount of helium to be injected into the medium-concentration helium solution is calculated, and the helium is injected into another group of helium solution configuration area (2) helium tanks (201), and then simulated water and helium are injected into another blending tank (9); the high-concentration helium solution is taken into account the loss of helium in the geological history period, and the concentration is twice that of the medium-concentration helium solution, and then simulated water and helium are injected into the remaining blending tank (9); After all the blending tanks (9) are filled with the corresponding liquid and gas, the heating pipe (10) of the blending box (4) is turned on, and the temperature of the blending box (4) is raised to the formation temperature by heating in a water bath. When the helium in the blending tank (9) is completely dissolved, the ability of natural gas to extract water-soluble helium is tested; Before the test, the chamber below the piston (14) is evacuated, the temperature of the piston (14) is preheated to the simulated temperature through the heating tube (10), and then high, medium and low concentration helium solutions are injected into the chamber in sequence, and finally natural gas is added; the second pressure gauge (13) monitors the pressure change in the chamber, and then controls the pressing force of the pressing device on the piston (14) to keep the pressure in the chamber stable at the set simulated pressure value during the entire gas injection process, and after it is left to stand until the designed sampling time, the collected gas sample is transported to the gas component detection device (22) through the pipeline connected to the gas outlet (21), and the volume of the gas under the formation temperature and pressure state is recorded by the second flow meter (16); the gas component detection device (22) obtains the extracted gas. The amount of helium in the natural gas layer after helium is taken out is used to calculate the proportion of extracted dissolved helium. At the same time, the helium solution is discharged from the bottom of the test cylinder (17), and the volume of the helium solution is obtained by the first flow meter (11). The discharged helium solution enters the gas-liquid separator (15). The gas component detection device (22) measures the helium concentration in the gas separated by the gas-liquid separator (15) and the helium solution, and estimates the helium concentration in the helium solution in the test cylinder (17). The amount of dissolved helium in the test cylinder (17) and the free helium in the gas layer are compared with the total amount of helium input to evaluate the amount of helium solution extracted by natural gas at different times, and thus determine the intensity of the extraction effect of natural gas on helium and the change law of its extraction rate.

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