A gas-liquid separation method for natural gas hydrate reservoir based on secondary sand fracturing

Abstract

The application relates to a gas-liquid separation and production method for a natural gas hydrate reservoir based on secondary sand fracturing, and the gas-liquid separation and production method comprises the following steps: S1, target reservoir division; S2, directional perforation is performed on an upper well section of the target reservoir; S3, two-time sand fracturing construction is performed on the upper well section of the target reservoir; S4, spiral perforation is performed on a lower well section of the target reservoir; and S5, a gas-liquid separation and production pipe column is used to perform gas-liquid two-phase synchronous separation and production on the target reservoir. The gas-liquid separation and production method provided by the application realizes gas-liquid two-phase separation in a reservoir matrix area through two-time sand fracturing construction, simultaneously realizes independent gas-liquid two-phase seepage in the reservoir and independent two-phase separation and production in a well hole by coupling two-time perforation technology and the gas-liquid separation and production pipe column.

Description

Technical Field

[0001] This invention relates to the field of natural gas hydrate reservoir development technology, specifically to a gas-liquid separation method for natural gas hydrate reservoirs based on secondary sand fracturing. Background Technology

[0002] Natural gas hydrates, also known as "combustible ice," are widely distributed in deep-sea sediments or permafrost on land. Due to their high resource density and wide global distribution, they have extremely high resource value and have become a long-term research hotspot in the oil and gas industry.

[0003] Currently, the main methods for extracting natural gas hydrates include depressurization, heating, chemical reagent injection, carbon dioxide replacement, mechanical-thermal recovery, and combinations of these methods. Under the original pressure and temperature conditions of the reservoir, natural gas hydrates exist in a solid phase. When the pressure is lower than the phase equilibrium pressure or the temperature is higher than the phase equilibrium temperature, the solid hydrates decompose into an aqueous and a gaseous phase through heat absorption. Therefore, during the extraction of natural gas hydrates, the porous medium of the reservoir matrix is ​​characterized by two-phase flow of gas and liquid. This two-phase flow within the matrix reduces the relative permeability of the gas and liquid phases, leading to a decrease in reservoir productivity. Furthermore, it easily causes water lock damage, resulting in a significant reduction in the effective pressure relief volume. In addition, during the extraction of natural gas hydrates, after the gas and liquid phases enter the wellbore, the production rate is relatively high. If a downhole separator is used for gas-liquid separation, the separation capacity and efficiency of the downhole gas-liquid separator must be high. Otherwise, gas lock-up of the liquid phase lift pump may occur, thus affecting the downhole drainage efficiency. If a mixed pump is used for gas-liquid co-production, the non-uniform gas-liquid seepage will cause drastic changes in gas content and may even lead to complex conditions such as slug flow, resulting in a significant reduction in the service life and pump efficiency of the mixed pump. Therefore, the performance reliability requirements for the mixed pump are extremely high.

[0004] In summary, during the exploitation of natural gas hydrates, the gas-liquid two-phase flow within the reservoir matrix and the efficient gas-liquid drainage within the wellbore are key technical challenges restricting the efficient exploitation of natural gas hydrates. How to achieve independent gas-liquid two-phase flow and independent extraction of the two phases within the wellbore is a technical problem that needs to be solved. Summary of the Invention

[0005] To address the above problems, the present invention aims to provide a gas-liquid separation method for natural gas hydrate reservoirs based on secondary sand fracturing. Compared with the prior art, the gas-liquid separation method provided by the present invention achieves gas-liquid two-phase separation in the reservoir matrix area through two sand fracturing operations. At the same time, it couples two perforation techniques and gas-liquid separation tubing to achieve independent seepage of gas and liquid phases in the reservoir and independent separation of two phases in the wellbore.

[0006] To achieve this objective, the present invention adopts the following technical solution: This invention provides a gas-liquid separation method for natural gas hydrate reservoirs based on secondary sand fracturing, the gas-liquid separation method comprising the following steps: S1, Target reservoir delineation; The target reservoir is divided into upper, middle and lower sections from top to bottom; S2, directional perforation is performed on the upper section of the target reservoir; S3, two sand-addition fracturing operations were carried out on the upper section of the target reservoir; The two sand-addition fracturing operations include: using fracturing fluid to carry high-density hydrophilic proppant to fill artificial fractures, the high-density hydrophilic proppant settling and laying at the bottom of the artificial fractures under gravity to form a liquid-phase dominant seepage channel; and using fracturing fluid to carry low-density gas-philic proppant to fill artificial fractures, the low-density gas-philic proppant laying at the top of the artificial fractures under buoyancy to form a gas-phase dominant seepage channel. S4, perform spiral perforation on the lower section of the target reservoir; S5 uses a gas-liquid separation pipeline to simultaneously separate gas and liquid phases in the target reservoir. The liquid phase migrates along the bottom of the artificial fracture, enters the wellbore through the spiral perforation holes in the lower section, and is discharged through the production tubing. The gas phase migrates along the top of the artificial fracture, enters the wellbore through the directional perforation holes in the upper section, and is produced through the annulus.

[0007] The gas-liquid separation method provided by this invention achieves gas-liquid two-phase separation in the reservoir matrix area through two sand fracturing operations. At the same time, it couples two perforation technologies and gas-liquid separation tubing to achieve independent seepage of gas and liquid phases in the reservoir and independent separation of two phases in the wellbore.

[0008] It should be noted that the purpose of performing two proppant fracturing operations in this invention is to form highly conductive fractures with a gas-loving top and a hydrophilic bottom in the artificial fractures by using two proppants with different densities and gas-liquid affinities. This will create gas-phase dominant seepage channels and liquid-phase dominant seepage channels in the artificial fractures, so as to further achieve simultaneous gas-liquid two-phase extraction.

[0009] Preferably, the thickness of the target reservoir in step S1 is 30~50m, for example, it can be 30m, 35m, 40m, 45m or 50m, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0010] In this invention, based on the engineering geological characteristics of the reservoir, the target reservoir for the drilling well is selected. The target reservoir needs to have a certain thickness, generally 30-50m. For reservoirs with a thickness greater than 50m, the middle 30-50m of the reservoir is generally preferred as the target reservoir. The target reservoir is divided into an upper section, a middle section, and a lower section from top to bottom, each independently occupying about 1 / 3 of the target reservoir thickness.

[0011] Preferably, the directional perforation in step S2 specifically includes: placing the production tubing perforation gun in the upper section of the target reservoir, performing 180° directional perforation along the direction of the maximum horizontal principal stress of the reservoir, and establishing a hydraulic fracturing channel.

[0012] In this invention, 180° directional perforation is used in the upper section of the target reservoir, with the perforation orientation aligned with the maximum horizontal principal stress of the reservoir. This effectively induces artificial fractures to initiate and extend in the target section during fracturing operations. Because the upper section where fracturing is performed is close to the overlying layer, it is affected by the overlying layer's geostress, lithology, and physical properties. The upward extension of the artificial fracture height is hindered, while the fracture length extends downwards, thus connecting the middle and lower sections of the target reservoir.

[0013] Preferably, the two sand-addition fracturing operations described in step S3 specifically include: S31, after the fracturing string is lowered to the target reservoir, the positioning seat is sealed with a packer; S32, artificial fractures are created by pumping pre-fracturing fluid into the fracturing tubing string, and the artificial fractures connect the middle and lower sections of the target reservoir; S33 utilizes fracturing fluid to carry high-density hydrophilic proppant to fill artificial fractures. The high-density hydrophilic proppant settles and lays at the bottom of the artificial fracture under gravity, forming a liquid-phase dominant seepage channel. S34, secondary pumping of pre-fluid opens artificial cracks; S35 utilizes fracturing fluid to carry low-density gas-loving proppant to fill artificial fractures. The low-density gas-loving proppant is laid on top of the artificial fractures under the action of buoyancy, forming a gas-phase dominant seepage channel.

[0014] In this invention, by pumping pre-fracturing fluid into the fracturing tubing, the artificial fracture height is hindered from extending upward due to the influence of overburden stress, lithology, and physical properties. At the same time as the fracture length extends, the fracture height extends downward, effectively connecting the middle and lower sections of the target reservoir.

[0015] Preferably, the density of the high-density hydrophilic proppant in step S3 is 2.0~2.5 g / cm³. 3 For example, it could be 2.0 g / cm³. 3 2.1g / cm 3 2.2g / cm3 2.3g / cm 3 2.4g / cm 3 Or 2.5g / cm 3 However, this does not limit the listed values; other unlisted values ​​within the range are also applicable.

[0016] Preferably, the surface of the high-density hydrophilic support contains hydrophilic functional groups.

[0017] Preferably, the hydrophilic functional group includes hydroxyl and / or carboxyl groups.

[0018] In this invention, the high-density hydrophilic proppant can be a commonly used high-density proppant in the art (such as ceramsite), with its surface coated or grafted with hydrophilic functional groups. Exemplarily, the high-density proppant can be immersed in a hydrophilic material containing hydroxyl and / or carboxyl groups (such as polyvinyl alcohol, polyethylene glycol, etc.) by chemical impregnation, forming a hydrophilic film containing hydroxyl and / or carboxyl groups on its surface, thereby obtaining the high-density hydrophilic proppant.

[0019] In this invention, when the high-density hydrophilic proppant is laid at the bottom of the crack, the micropore channels formed between the particles are hydrophilic and gas-repellent. The gas phase has extremely high seepage resistance under the action of capillary force, while the water phase has low seepage resistance, which is conducive to water phase seepage, thereby establishing a liquid phase dominant seepage channel at the bottom of the crack.

[0020] Preferably, the density of the low-density gas-loving proppant in step S3 is 1.0~1.2 g / cm³. 3 For example, it could be 1.0 g / cm³. 3 1.1g / cm 3 Or 1.2g / cm 3 However, this does not limit the listed values; other unlisted values ​​within the range are also applicable.

[0021] Preferably, the surface of the low-density gas-loving proppant contains gas-loving functional groups.

[0022] Preferably, the gas-loving functional group includes alkyl and / or aryl groups.

[0023] Preferably, the alkyl group includes methyl and / or ethyl.

[0024] Preferably, the aryl group includes a phenyl group.

[0025] In this invention, the low-density gas-loving proppant can be a commonly used low-density proppant in the art (such as resin balls), with its surface coated or grafted with gas-loving functional groups. For example, the low-density gas-loving proppant can be immersed in a gas-loving material containing alkyl and / or aryl groups (such as a silane coupling agent) by chemical impregnation, forming a gas-loving film containing alkyl and / or aryl groups on its surface, thereby obtaining the low-density gas-loving proppant.

[0026] In this invention, when the low-density gas-loving proppant is laid on the top of the crack, the micropore channels formed between the particles are hydrophobic and gas-loving. The aqueous phase has extremely high seepage resistance under the action of capillary force, while the gas phase has low seepage resistance, which is conducive to gas phase seepage, thereby establishing a gas phase dominant seepage channel at the top of the crack.

[0027] Preferably, step S4, spiral perforation, specifically includes: placing the production tubing transfer perforation gun in the lower section of the target reservoir, performing spiral perforation operations, and establishing a seepage channel between the wellbore and the artificial fracture in the lower section.

[0028] Preferably, the perforation density of the spiral perforation operation in step S4 is ≥21 holes / meter, for example, it can be 21 holes / meter, 22 holes / meter, 24 holes / meter, 25 holes / meter, 26 holes / meter or 27 holes / meter, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the perforation phase of the spiral perforation operation is ≤90°, for example, it can be 90°, 85°, 80°, 75°, 70°, 65° or 60°, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the perforation depth of the spiral perforation operation is >1m, for example, it can be 1.5m, 2m, 2.5m or 3m, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] In this invention, a high-density, deep-penetrating spiral perforation operation can be carried out on the lower well section through a secondary perforation operation, namely spiral perforation. The perforation density is required to be ≥21 holes / meter, the perforation phase is ≤90°, and the perforation depth is >1m. The holes of the spiral perforation can maximize the connection between artificial fractures in the reservoir, thereby effectively establishing a seepage channel between the lower well section and the artificial fractures.

[0032] Preferably, the gas-liquid separation production string in step S5 includes: a production tubing, a production packer, a multiphase mixing pump, and a power cable.

[0033] Preferably, the simultaneous gas-liquid two-phase sampling in step S5 specifically includes: S51, the multiphase mixed-transport pump, production packer and production tubing are assembled sequentially from bottom to top inside the production casing. The production packer is seated in the middle section of the well and the annulus is sealed. The power cable passes through the production packer and connects to the multiphase mixed-transport pump. The spiral perforation holes, multiphase mixed-transport pump and production tubing in the lower section form a liquid phase production channel. The directional perforation holes and annulus in the upper section form a gas phase production channel. S52, the multiphase mixed-transport pump is started. The pore pressure of the reservoir decreases, and the natural gas hydrate decomposes into gas and liquid phases. Under the action of different capillary forces formed by the high-density hydrophilic proppant and the low-density gas-philic proppant in the artificial fracture, the liquid phase moves along the bottom of the artificial fracture and enters the wellbore through the spiral perforation holes in the lower section. Under the lifting action of the multiphase mixed-transport pump, the liquid is discharged along the production tubing. The gas phase moves along the top of the artificial fracture and enters the wellbore through the directional perforation holes in the upper section and achieves gas production through the annulus.

[0034] In this invention, a production packer is installed in the middle section of the well, between the upper and lower sections. The production packer seals the annulus, thereby establishing an independent production pipeline for the production tubing and the annulus. The lower part of the production tubing is connected to a multiphase mixed-transfer pump, which is powered by a power cable. This enables the production of the liquid phase in the lower section of the target reservoir, while the annulus allows for the drainage of the gas phase in the upper section of the target reservoir.

[0035] Compared with the prior art, the present invention has the following beneficial effects: (1) The gas-liquid separation method provided by the present invention involves two proppant fracturing operations with sand addition. By using two proppants with different densities and different gas-liquid affinities, a high conductivity fracture with a gas-loving top and a hydrophilic bottom is formed in the artificial fracture. This forms a gas-phase dominant seepage channel and a liquid-phase dominant seepage channel in the artificial fracture, achieving gas-liquid two-phase separation in the reservoir matrix area. Furthermore, the two-perforation technology and the gas-liquid separation tubing are coupled to finally achieve independent seepage of gas and liquid phases in the reservoir and independent separation of two phases in the wellbore, providing an efficient gas-liquid separation method for natural gas hydrate reservoirs.

[0036] (2) The gas-liquid separation method provided by the present invention can effectively avoid water lock damage caused by gas-liquid two-phase seepage, avoid the use of downhole separators, extend the service life of the mixed pump, improve drainage efficiency, and ensure reservoir production capacity. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the directional perforation stage provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the gas-liquid two-phase simultaneous extraction stage provided in Embodiment 1 of the present invention; In the diagram, 1-Production casing; 2-Fracturing string; 3-Slips; 4-Packer; 5-Artificial fracture; 6-Low-density gas-loving proppant; 7-High-density hydrophilic proppant; 8-Production tubing; 9-Multiphase mixing pump; 10-Production packer; 11-Power cable; 12-Directional perforation orifice; 13-Helical perforation orifice. Detailed Implementation

[0038] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0039] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0040] Example 1 This embodiment provides a gas-liquid separation method for natural gas hydrate reservoirs based on secondary sand fracturing, such as... Figure 1 and Figure 2 As shown, the gas-liquid separation method includes the following steps: S1, Target reservoir delineation; Based on the engineering geological characteristics of the reservoir in the well, the target reservoir with a thickness of 45m was selected. The target reservoir was divided into upper section, middle section and lower section from top to bottom, each being 1 / 3 of the target reservoir thickness. S2, directional perforation is performed on the upper section of the target reservoir; The production tubing perforation gun is placed in the upper section of the target reservoir, and a 180° directional perforation operation is carried out along the direction of the maximum horizontal principal stress of the reservoir. The perforation project penetrates the production casing 1 to form a directional perforation hole 12. S3, two sand-addition fracturing operations were carried out on the upper section of the target reservoir; S31, after the fracturing string 2 is lowered to the target reservoir, the packer 4 is positioned and sealed. The slip 3 bites into the production casing 1, thereby supporting the packer 4. S32, artificial fracture 5 is created by pumping pre-fracturing fluid through fracturing tubing string 2. Due to the influence of overburden stress, lithology, physical properties, etc., the upward extension of the fracture height of artificial fracture 5 is hindered. While the fracture length extends, the fracture height extends downward, effectively connecting the middle and lower sections of the target reservoir. S33. High-density hydrophilic proppant 7 carried by fracturing fluid is used to fill artificial fractures 5. The preparation method of high-density hydrophilic proppant 7 is as follows: ceramsite is soaked in a polyvinyl alcohol solution and stirred at 20~25℃ for 1~2 hours, then drained, and subsequently heat-treated at 100~200℃ to obtain a high-density hydrophilic proppant with a density of 2.0~2.5 g / cm³. 3 The high-density hydrophilic proppant 7 settles and is laid at the bottom of the artificial crack 5 under the action of gravity. The micropore channels between the particles of the high-density hydrophilic proppant 7 are hydrophilic and air-repellent. The gas phase has great seepage resistance under the action of capillary force, while the water phase has less seepage resistance, which is conducive to water phase seepage, thus establishing a liquid phase dominant seepage channel at the bottom of the artificial crack 5. S34, Secondary pumping of pre-fluid opens artificial crack 5; After the high-density hydrophilic proppant 7 has completely settled, the pre-fracturing fluid is pumped in again, and the artificial fracture 5 is reopened. S35, the artificial fracture 5 is filled using fracturing fluid carrying a low-density gas-loving proppant 6. The low-density gas-loving proppant 6 is prepared by: immersing resin balls in silane coupling agent KH550, stirring at 20-25℃ for 1-2 hours, then draining, and finally heat-treating at 80-120℃ to solidify the coupling agent, resulting in a low-density gas-loving proppant with a density of 1.0-1.2 g / cm³. 3 The low-density gas-loving proppant 6 is laid on the top of the artificial crack 5 under the action of buoyancy. The micropore channels between the particles of the low-density gas-loving proppant 6 are hydrophobic and gas-loving. The water phase has a great seepage resistance under the action of capillary force, while the gas phase has a small seepage resistance, which is conducive to gas phase seepage, thus establishing a gas phase dominant seepage channel at the top of the artificial crack 5. S4, perform spiral perforation on the lower section of the target reservoir; The production tubing perforation gun is placed in the lower section of the target reservoir for spiral perforation operation. The perforation density is 21 holes / meter, the perforation phase is 90°, and the perforation depth is 1.5m. Spiral perforation holes 13 are formed in the production casing 1 to establish a seepage channel between the wellbore in the lower section and the artificial fracture 5. S5 uses a gas-liquid separation pipeline to simultaneously separate gas and liquid phases in the target reservoir. S51, the multiphase mixed-transport pump 9, production packer 10 and production tubing 8 are assembled from bottom to top in the production casing 1. The production tubing 8 is extended to the target well depth. The production packer 10 is seated in the middle section of the well and the annulus is sealed. The power cable 11 passes through the production packer 10 and connects to the multiphase mixed-transport pump 9. The spiral perforation hole 13, multiphase mixed-transport pump 9 and production tubing 8 in the lower section form a liquid phase production channel. The directional perforation hole 12 and annulus form a gas phase production channel in the upper section. S52, the multiphase mixed-transport pump 9 is started, the pore pressure of the reservoir decreases, and the natural gas hydrate decomposes into gas and liquid phases. Under the action of different capillary forces formed by the high-density hydrophilic proppant 7 and the low-density gas-loving proppant 6 in the artificial fracture 5, the micropore channels between the particles of the high-density hydrophilic proppant 7 are hydrophilic and gas-repellent, and the liquid phase moves along the bottom of the artificial fracture 5 and enters the wellbore through the spiral perforation hole 13 in the lower section. Under the lifting action of the multiphase mixed-transport pump 9, the liquid is discharged along the production tubing 8. The micropore channels between the particles of the low-density gas-loving proppant 6 are hydrophobic and gas-loving, and the gas phase moves along the top of the artificial fracture 5 and enters the wellbore through the directional perforation hole 12 in the upper section and achieves gas production through the annulus.

[0041] In summary, the gas-liquid separation method provided by this invention achieves gas-liquid two-phase separation in the reservoir matrix area through two sand fracturing operations. At the same time, it couples two perforation techniques and gas-liquid separation tubing to achieve independent gas-liquid two-phase seepage in the reservoir and independent two-phase separation in the wellbore.

[0042] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A gas-liquid separation method for natural gas hydrate reservoirs based on secondary sand fracturing, characterized in that, The gas-liquid separation method includes the following steps: S1, Target reservoir delineation; The target reservoir is divided into upper, middle and lower sections from top to bottom; S2, directional perforation is performed on the upper section of the target reservoir; S3, two sand-addition fracturing operations were carried out on the upper section of the target reservoir; The two sand-addition fracturing operations include: using fracturing fluid to carry high-density hydrophilic proppant to fill artificial fractures, the high-density hydrophilic proppant settling and laying at the bottom of the artificial fractures under gravity to form a liquid-phase dominant seepage channel; and using fracturing fluid to carry low-density gas-philic proppant to fill artificial fractures, the low-density gas-philic proppant laying at the top of the artificial fractures under buoyancy to form a gas-phase dominant seepage channel. S4, perform spiral perforation on the lower section of the target reservoir; S5 uses a gas-liquid separation pipeline to simultaneously separate gas and liquid phases in the target reservoir. The liquid phase migrates along the bottom of the artificial fracture, enters the wellbore through the spiral perforation holes in the lower section, and is discharged through the production tubing. The gas phase migrates along the top of the artificial fracture, enters the wellbore through the directional perforation holes in the upper section, and is produced through the annulus.

2. The gas-liquid separation method according to claim 1, characterized in that, The thickness of the target reservoir in step S1 is 30~50m.

3. The gas-liquid separation method according to claim 1 or 2, characterized in that, The directional perforation described in step S2 specifically includes: The production tubing perforation gun is placed in the upper section of the target reservoir, and 180° directional perforation is carried out along the direction of the maximum horizontal principal stress of the reservoir to establish a hydraulic fracturing channel.

4. The gas-liquid separation method according to any one of claims 1 to 3, characterized in that, Step S3 specifically includes the two sand-addition fracturing operations: S31, after the fracturing string is lowered to the target reservoir, the positioning seat is sealed with a packer; S32, artificial fractures are created by pumping pre-fracturing fluid into the fracturing tubing string, and the artificial fractures connect the middle and lower sections of the target reservoir; S33 utilizes fracturing fluid to carry high-density hydrophilic proppant to fill artificial fractures. The high-density hydrophilic proppant settles and lays at the bottom of the artificial fracture under gravity, forming a liquid-phase dominant seepage channel. S34, secondary pumping of pre-fluid opens artificial cracks; S35 utilizes fracturing fluid to carry low-density gas-loving proppant to fill artificial fractures. The low-density gas-loving proppant is laid on top of the artificial fractures under the action of buoyancy, forming a gas-phase dominant seepage channel.

5. The gas-liquid separation method according to any one of claims 1 to 4, characterized in that, The density of the high-density hydrophilic proppant mentioned in step S3 is 2.0~2.5 g / cm³. 3 ; Preferably, the surface of the high-density hydrophilic support contains hydrophilic functional groups; Preferably, the hydrophilic functional group includes hydroxyl and / or carboxyl groups.

6. The gas-liquid separation method according to any one of claims 1 to 5, characterized in that, The low-density gas-loving proppant mentioned in step S3 has a density of 1.0~1.2 g / cm³. 3 ; Preferably, the surface of the low-density acetophilic proppant contains acetophilic functional groups; Preferably, the gas-loving functional group includes alkyl and / or aryl groups; Preferably, the alkyl group includes methyl and / or ethyl; Preferably, the aryl group includes a phenyl group.

7. The gas-liquid separation method according to any one of claims 1 to 6, characterized in that, Step S4, the spiral perforation, specifically includes: The production tubing perforation gun is placed in the lower section of the target reservoir to perform spiral perforation operations, establishing a seepage channel between the wellbore and the artificial fracture in the lower section.

8. The gas-liquid separation method according to any one of claims 1 to 7, characterized in that, The perforation density of the spiral perforation operation described in step S4 is ≥21 holes / meter; Preferably, the perforation phase of the spiral perforation operation is ≤90°; Preferably, the perforation depth of the spiral perforation operation is >1m.

9. The gas-liquid separation method according to any one of claims 1 to 8, characterized in that, The gas-liquid separation production line in step S5 includes: production tubing, production packer, multiphase mixing pump, and power cable.

10. The gas-liquid separation method according to claim 9, characterized in that, Step S5, the simultaneous gas-liquid two-phase sampling, specifically includes: S51, the multiphase mixed-transport pump, production packer and production tubing are assembled sequentially from bottom to top inside the production casing. The production packer is seated in the middle section of the well and the annulus is sealed. The power cable passes through the production packer and connects to the multiphase mixed-transport pump. The spiral perforation holes, multiphase mixed-transport pump and production tubing in the lower section form a liquid phase production channel. The directional perforation holes and annulus in the upper section form a gas phase production channel. S52, the multiphase mixed-transport pump is started. The pore pressure of the reservoir decreases, and the natural gas hydrate decomposes into gas and liquid phases. Under the action of different capillary forces formed by the high-density hydrophilic proppant and the low-density gas-philic proppant in the artificial fracture, the liquid phase moves along the bottom of the artificial fracture and enters the wellbore through the spiral perforation holes in the lower section. Under the lifting action of the multiphase mixed-transport pump, the liquid is discharged along the production tubing. The gas phase moves along the top of the artificial fracture and enters the wellbore through the directional perforation holes in the upper section and achieves gas production through the annulus.

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