Method and device for calculating gas storage capacity of aquifer gas storage

Abstract

The invention relates to the technical field of natural gas underground storage, gas reservoir engineering and indoor experiments, and particularly discloses a method and device for calculating the gas storage capacity of an aquifer gas storage. Dividing the pore volume occupied by the gas reservoir reserves of the water-bearing stratum underground gas storage into accumulated water yield, water body elastic compression amount, the pore volume contributed by rock pore swelling amount and the volume of gas dissolved in formation water; calculating cumulative water yield, residual water elastic compression amount, pore volume contributed by rock pore swelling amount and volume of gas dissolved in formation water in sequence; and according to the pore volume of gas storage and the volume of gas dissolved in formation water, the gas storage capacity of the aquifer gas storage under the set injection-production pressure condition is determined. According to the method provided by the invention, the calculation precision of the gas storage capacity of the aquifer gas storage is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical fields of underground natural gas storage, gas reservoir engineering and indoor experiments, and in particular to a method and device for calculating the gas storage capacity of an aquifer gas storage reservoir. Background Art

[0002] Aquifer gas storage is an artificial gas reservoir formed by injecting natural gas into underground aquifers with storage conditions through high-pressure gas injection to drive water. Gas storage capacity is an important indicator to measure the storage capacity and regulation capacity of aquifer gas storage. Scientific and accurate calculation of gas storage capacity is the premise and basis for the construction of aquifer gas storage and efficient and economical operation. The calculation of gas storage capacity of aquifer gas storage needs to consider the impact of high-pressure gas injection on water compression and rock pore rebound on gas storage space.

[0003] At present, the calculation method of storage capacity for existing depleted oil and gas reservoirs has not yet considered the impact of high pressure on the gas storage space, resulting in poor calculation accuracy of the existing calculation method for calculating the gas storage capacity under the set injection and production pressure conditions during the high-pressure gas injection and water displacement process of aquifer gas storage. Summary of the invention

[0004] The purpose of the present invention is to provide a method and device for calculating the gas storage capacity of an aquifer gas storage reservoir, so as to solve the technical problem in the prior art of lacking a method for calculating the gas storage capacity under set injection and production pressure conditions during high-pressure gas injection and water displacement in an aquifer gas storage reservoir.

[0005] In order to solve the above technical problems, the present invention specifically provides the following technical solutions: A method for calculating the gas storage capacity of an aquifer gas storage reservoir, comprising: According to the material balance principle, the gas storage capacity of the aquifer gas storage reservoir under the set injection and production pressure conditions is divided into the cumulative water production, the elastic compression of the water body, the pore volume contributed by the rock pore expansion, and the gas volume dissolved in the formation water, and they are calculated in sequence; Based on the calculation results, the pore volume provided by the expansion of rock pores due to the increase in pressure after high-pressure gas injection into the formation is obtained. , the pore volume of the gas reservoir after the formation water is released from the aquifer gas storage reservoir 2. After the gas is injected into the formation under high pressure, the water body shrinks due to the pressure increase and provides pore volume and the volume of natural gas dissolved in formation water ; Combined gas volume coefficient , calculate the gas storage capacity of the aquifer gas storage under the set injection and production pressure conditions , the calculation formula is as follows: ; ; in, is the gas compressibility factor; is the formation temperature; is the formation pressure; is the ground standard pressure; The standard ground temperature.

[0006] As a preferred embodiment of the present invention, the volume of water trapped in the aquifer structure of the aquifer gas storage reservoir and the rock compressibility coefficient are used to determine the pore volume provided by the expansion of the rock pores due to the increase in pressure after the gas is injected into the formation under high pressure. , the calculation formula is: ; in, The pore volume provided for rock pore expansion; is the rock compression coefficient; It is the change in formation pressure after gas injection.

[0007] As a preferred solution of the present invention, the pore volume of the gas storage capacity of the gas reservoir after the formation water is released from the aquifer gas storage reservoir is determined according to the relationship between the cumulative water production and the pressure data and the water volume coefficient. , the calculation formula is; ; in, is the cumulative water production, is the water volume coefficient.

[0008] As a preferred embodiment of the present invention, the pore volume provided by the water body shrinking due to the pressure increase after the gas is injected into the formation under high pressure is determined according to the water body volume and water compressibility coefficient of the aquifer gas storage reservoir. , the calculation formula is: ; in, is the water compressibility coefficient, Cumulative water production.

[0009] As a preferred embodiment of the present invention, the volume of natural gas dissolved in formation water is determined according to the temperature of the natural gas reservoir, the solubility of the natural gas in the formation water at a set pressure, and the residual water volume of the water-containing structural trap. , the calculation formula is: ; in, is the solubility of natural gas in formation water; It is the density of natural gas under the conditions of formation temperature and pressure.

[0010] As a preferred solution of the present invention, the two-dimensional / three-dimensional seismic data, drilling, logging, well logging and core reservoir physical property test analysis data are used to obtain the aquifer structural closure area, aquifer reservoir thickness and effective porosity and aquifer water density data to determine the aquifer structural water volume. The calculation formula is as follows: ; in, is the water volume of the aquifer gas storage reservoir; is the distribution area of ​​water in aquifer gas storage reservoir; is the thickness of the aquifer; Φ is the effective porosity of the aquifer reservoir; is the density of aquifer water; is the water volume coefficient under formation temperature and pressure conditions; Obtain data on water-bearing formation pressure, temperature, and reservoir rock mineral characteristics to determine water body compressibility, volume coefficient, rock compressibility, and solubility of natural gas in formation water.

[0011] As a preferred solution of the present invention, the proposed gas storage reservoir drilling pressure-extraction test is used to obtain the cumulative water production and pressure data, and establish a functional relationship between the cumulative water production and pressure of the gas reservoir to characterize the relationship between the remaining water and pressure of the gas storage reservoir under different pressure injection and production conditions; The functional relationship between the remaining water volume and pressure of the aquifer gas storage reservoir is calculated using the following formula: ; in, is the ground injection pressure, is the cumulative water production, It is the functional relationship between the surface gas injection pressure and the cumulative water production of the reservoir.

[0012] The present invention provides a device for calculating the gas storage capacity of an aquifer gas storage reservoir for realizing the gas storage capacity calculation method of the aquifer gas storage reservoir, comprising: A module for determining the volume of water bodies in aquifer structures, which is used to obtain the data of the aquifer structure closure area, the thickness and effective porosity of the water-bearing reservoir, and the density of the aquifer water bodies, and determine the volume of water bodies in aquifer structures; A functional relationship determination module is used to obtain the gas reservoir pressure and cumulative water production data of the aquifer gas storage reservoir, and obtain the functional relationship between the cumulative water production and the pressure; The pore volume division module is used to divide the pore volume occupied by the dynamic reserves of the gas reservoir into three pore volumes: cumulative water production, water elastic compression, and rock pore expansion according to the material balance principle; A pore volume determination module, which determines the pore volume contributed by each pore volume to the dynamic reserves of the gas reservoir according to the pore volume occupied by the dynamic reserves of the gas reservoir; The gas storage capacity determination module determines the gas storage capacity according to the pore volume and dissolved gas volume of the gas stored in the gas storage reservoir.

[0013] As a preferred solution of the present invention, a computer-readable storage medium is included, wherein the computer-readable storage medium stores a computer program, wherein the computer program includes an aquifer structure water volume determination module, a functional relationship determination module, a pore volume division module, a pore volume determination module, and a gas storage capacity determination module; The computer program is used to run the method for calculating the gas storage capacity of an aquifer gas storage reservoir. When the computer program is executed by a processor, the method for calculating the gas storage capacity of an aquifer gas storage reservoir under set injection and production pressure conditions is implemented.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention can solve the problem that the current storage capacity calculation method is not suitable for the storage capacity evaluation of aquifer gas storage reservoirs. Aiming at the influence of the high-pressure gas injection working mode of aquifer gas storage reservoirs on water compression and rock pore rebound on the gas storage space, the present invention proposes that according to the material balance principle, the gas storage capacity of the gas storage reservoir under the set injection and production pressure conditions is divided into the cumulative water production after the gas is injected into the formation under high pressure, that is, the sum of the squeezed water volume and the produced water volume, the elastic compression of the water body, the pore volume contributed by the rock pore expansion, and the gas volume dissolved in the formation water, so as to determine the gas storage capacity of the aquifer gas storage reservoir under the set injection and production pressure conditions. The method provided by the present invention greatly improves the calculation accuracy of the gas storage capacity of the aquifer gas storage reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0016] Figure 1 Schematic diagram of a flow chart of a method for calculating the gas storage capacity of an aquifer gas storage reservoir in an embodiment of the present invention; Figure 2 Detailed description of the embodiment of the method for calculating the storage capacity of an aquifer gas storage reservoir in the embodiment of the present invention; Figure 3 It is a schematic diagram of the division of pore volume occupied by dynamic reserves of gas reservoirs and the volume of dissolved gas in an embodiment of the present invention; Figure 4 Schematic diagram of a storage capacity calculation device for an aquifer gas storage reservoir in an embodiment of the present invention.

[0017] The numbers in the figure represent the following: 500 - a device for calculating the gas storage capacity of an aquifer gas storage reservoir; 510 - a readable storage medium; 520 - a computer processor; 530 - a computer program. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] like Figures 1 to 4 As shown, the present invention provides a method for calculating the gas storage capacity of an aquifer gas storage reservoir, comprising: According to the material balance principle, the gas storage capacity of the aquifer gas storage reservoir under the set injection and production pressure conditions is divided into the cumulative water production, the elastic compression of the water body, the pore volume contributed by the rock pore expansion, and the gas volume dissolved in the formation water, and they are calculated in sequence; Based on the calculation results, the pore volume provided by the expansion of rock pores due to the increase in pressure after high-pressure gas injection into the formation is obtained. , the pore volume of the gas reservoir after the formation water is released from the aquifer gas storage reservoir 2. After the gas is injected into the formation under high pressure, the water body shrinks due to the pressure increase and provides pore volume and the volume of natural gas dissolved in formation water ; Combined gas volume coefficient , calculate the gas storage capacity of the aquifer gas storage under the set injection and production pressure conditions , the calculation formula is as follows: ; ; in, is the gas compressibility factor; is the formation temperature; is the formation pressure; is the ground standard pressure; The standard ground temperature.

[0020] In this embodiment, based on the material balance principle, the volume changes of the formation pore space and the fluid stored therein are considered under any set gas injection pressure conditions.

[0021] The storage capacity calculation method and device for an aquifer gas storage reservoir proposed in this embodiment can solve the problem that the current storage capacity calculation method is not suitable for storage capacity evaluation of an aquifer gas storage reservoir.

[0022] In view of the impact of high-pressure gas injection working mode of aquifer gas storage on water compression and rock pore rebound on gas storage space, it is proposed to divide the gas storage capacity of the gas storage reservoir at any time into the cumulative water production after high-pressure gas injection into the formation, that is, the squeezed water volume + produced water volume, as well as the pore volume contributed by the elastic compression of the water body and the expansion of the rock pores and the volume of gas dissolved in the formation water according to the principle of material balance, so as to determine the gas storage capacity of the aquifer gas storage reservoir at any time.

[0023] The embodiment of the present invention determines the contribution of the pore volume provided by the expansion of rock pores due to increased pressure after high-pressure gas injection into the formation to the gas storage capacity of the aquifer gas storage reservoir through the volume of water trapped in the aquifer structure; determines the cumulative water production under different gas injection pressure conditions through the functional relationship between the cumulative water production and pressure, and determines the contribution of the pore volume of the cumulative water production of the aquifer gas storage reservoir to the gas storage capacity of the gas reservoir, the pore volume provided by the contraction of the remaining water body due to increased pressure, and the dissolved volume of natural gas in the remaining formation water to the gas storage capacity of the aquifer gas storage reservoir based on the cumulative water production, which can effectively improve the calculation accuracy of the gas storage capacity of the gas storage reservoir. This implementation greatly improves the calculation accuracy of the gas storage capacity of the aquifer gas storage reservoir.

[0024] The volume of water trapped in the aquifer structure of the aquifer gas storage and the rock compressibility coefficient are used to determine the pore volume provided by the expansion of rock pores due to the increase in pressure after the gas is injected into the formation at high pressure. , the calculation formula is: ; in, The pore volume provided for rock pore expansion; is the rock compression coefficient; It is the change in formation pressure after gas injection.

[0025] The pore volume of the gas reservoir after the formation water is released from the aquifer gas storage reservoir is determined based on the relationship between the cumulative water production and the pressure data and the water volume coefficient. , the calculation formula is; ; in, is the cumulative water production, is the water volume coefficient.

[0026] Determine the pore volume provided by the water body shrinking due to pressure increase after high-pressure gas injection into the formation based on the water body volume and water compressibility coefficient of the aquifer gas storage reservoir , the calculation formula is: ; in, is the water compressibility coefficient, Cumulative water production.

[0027] The volume of natural gas dissolved in formation water is determined based on the temperature of the natural gas reservoir, the solubility of natural gas in the formation water at a set pressure, and the remaining water volume in the water-bearing structural trap. , the calculation formula is: ; in, is the solubility of natural gas in formation water; It is the density of natural gas under the conditions of formation temperature and pressure.

[0028] Using 2D / 3D seismic data, drilling, logging, well logging and core reservoir physical property test analysis data, the aquifer structural closure area, aquifer reservoir thickness and effective porosity and aquifer water density data are obtained to determine the aquifer structural water volume. The calculation formula is as follows: ; in, is the water volume of the aquifer gas storage reservoir; is the distribution area of ​​water in aquifer gas storage reservoir; is the thickness of the aquifer; Φ is the effective porosity of the aquifer reservoir; is the density of aquifer water; is the water volume coefficient under formation temperature and pressure conditions; Obtain data on water-bearing formation pressure, temperature, and reservoir rock mineral characteristics to determine water body compressibility, volume coefficient, rock compressibility, and solubility of natural gas in formation water.

[0029] The proposed gas storage drilling pressure-extraction test was used to obtain the cumulative water production and pressure data, and the functional relationship between the cumulative water production and pressure of the gas reservoir was established to characterize the relationship between the remaining water and pressure of the gas storage under different pressure injection and production conditions; ; The functional relationship between the remaining water volume and pressure of the aquifer gas storage reservoir is calculated using the following formula: ; in, is the ground injection pressure, is the cumulative water production, It is the functional relationship between the surface gas injection pressure and the cumulative water production of the reservoir.

[0030] This embodiment provides a device for calculating the gas storage capacity of an aquifer gas storage reservoir for implementing the method for calculating the gas storage capacity of an aquifer gas storage reservoir, characterized in that it includes: A module for determining the volume of water bodies in aquifer structures, which is used to obtain the data of the aquifer structure closure area, the thickness and effective porosity of the water-bearing reservoir, and the density of the aquifer water bodies, and determine the volume of water bodies in aquifer structures; A functional relationship determination module is used to obtain the gas reservoir pressure and cumulative water production data of the aquifer gas storage reservoir, and obtain the functional relationship between the cumulative water production and the pressure; The pore volume division module is used to divide the pore volume occupied by the dynamic reserves of the gas reservoir into three pore volumes: cumulative water production, water elastic compression, and rock pore expansion according to the material balance principle; A pore volume determination module, which determines the pore volume contributed by each pore volume to the dynamic reserves of the gas reservoir according to the pore volume occupied by the dynamic reserves of the gas reservoir; The gas storage capacity determination module determines the gas storage capacity according to the pore volume and dissolved gas volume of the gas stored in the gas storage reservoir.

[0031] An aquifer gas storage reservoir gas storage capacity calculation device 500 specifically includes a computer readable storage medium 510, the computer readable storage medium 510 stores a computer program 530, and the computer program 530 includes an aquifer structure water body volume determination module, a function relationship determination module, a pore volume division module, a pore volume determination module, and a gas storage capacity determination module; The computer program 530 is used to run the method for calculating the gas storage capacity of an aquifer gas storage reservoir. When the computer program is executed by the processor 520, the method for calculating the gas storage capacity of an aquifer gas storage reservoir under set injection and production pressure conditions is implemented.

[0032] The term "and / or" herein only describes an association relationship, indicating that three relationships may exist. For example, A and / or B may represent the following three situations: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C may represent including any one or more elements selected from the set consisting of A, B, and C.

[0033] In the description of this specification, the terms "include", "including", "have", "contain", etc. are all open terms, which mean including but not limited to. The descriptions with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", etc. mean that the specific features, structures or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. The order of steps involved in each embodiment is used to schematically illustrate the implementation of the present application, and the order of steps is not limited and can be appropriately adjusted as needed.

[0034] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. A method for calculating the gas storage capacity of an aquifer gas storage reservoir, characterized in that: include: According to the material balance principle, the gas storage capacity of the aquifer gas storage reservoir under the set injection and production pressure conditions is divided into the cumulative water production, the elastic compression of the water body, the pore volume contributed by the rock pore expansion, and the gas volume dissolved in the formation water, and they are calculated in sequence; Based on the calculation results, the pore volume provided by the expansion of rock pores due to the increase in pressure after high-pressure gas injection into the formation is obtained. , the pore volume of the gas reservoir after the formation water is released from the aquifer gas storage reservoir 2. After the gas is injected into the formation under high pressure, the water body shrinks due to the pressure increase and provides pore volume and the volume of natural gas dissolved in formation water ; Combined gas volume coefficient , calculate the gas storage capacity of the aquifer gas storage under the set injection and production pressure conditions , the calculation formula is as follows: ； ； in, is the gas compressibility factor; is the formation temperature; is the formation pressure; is the ground standard pressure; The standard ground temperature.

2. The method for calculating the gas storage capacity of an aquifer gas storage reservoir according to claim 1, characterized in that: The volume of water trapped in the aquifer structure of the aquifer gas storage and the rock compressibility coefficient are used to determine the pore volume provided by the expansion of rock pores due to the increase in pressure after the gas is injected into the formation at high pressure. , the calculation formula is: ； in, The pore volume provided for rock pore expansion; is the rock compression coefficient; It is the change in formation pressure after gas injection.

3. The method for calculating the gas storage capacity of an aquifer gas storage reservoir according to claim 1, characterized in that: The pore volume of the gas reservoir after the formation water is released from the aquifer gas storage reservoir is determined based on the relationship between the cumulative water production and the pressure data and the water volume coefficient. , the calculation formula is; ； in, is the cumulative water production, is the water volume coefficient.

4. The method for calculating the gas storage capacity of an aquifer gas storage reservoir according to claim 1, characterized in that: Determine the pore volume provided by the water body shrinking due to pressure increase after high-pressure gas injection into the formation based on the water body volume and water compressibility coefficient of the aquifer gas storage reservoir , the calculation formula is: ； in, is the water compressibility coefficient, Cumulative water production.

5. The method for calculating the gas storage capacity of an aquifer gas storage reservoir according to claim 1, characterized in that: The volume of natural gas dissolved in formation water is determined based on the temperature of the natural gas reservoir, the solubility of natural gas in the formation water at a set pressure, and the remaining water volume in the water-bearing structural trap. , the calculation formula is: ； in, is the solubility of natural gas in formation water; It is the density of natural gas under formation temperature and pressure conditions.

6. The method for calculating the gas storage capacity of an aquifer gas storage reservoir according to claim 2, characterized in that: Using 2D / 3D seismic data, drilling, logging, well logging and core reservoir physical property test analysis data, the aquifer structural closure area, aquifer reservoir thickness and effective porosity and aquifer water density data are obtained to determine the aquifer structural water volume. The calculation formula is as follows: ； in, is the volume of water in the aquifer gas storage reservoir; is the distribution area of ​​water in aquifer gas storage reservoir; is the thickness of the aquifer; Φ is the effective porosity of the aquifer reservoir; is the density of aquifer water; is the water volume coefficient under formation temperature and pressure conditions; Obtain data on water-bearing formation pressure, temperature, and reservoir rock mineral characteristics to determine water body compressibility, volume coefficient, rock compressibility, and solubility of natural gas in formation water.

7. A method for calculating the gas storage capacity of an aquifer gas storage reservoir according to any one of claims 1 to 5, characterized in that: The proposed gas storage drilling pressure-extraction test was used to obtain the cumulative water production and pressure data, and to establish a functional relationship between the cumulative water production and pressure of the gas reservoir to characterize the relationship between the remaining water and pressure of the gas storage under different pressure injection and production conditions; The functional relationship between the remaining water volume and pressure of the aquifer gas storage reservoir is calculated using the following formula: ； in, is the ground injection pressure, is the cumulative water production, It is the functional relationship between the surface gas injection pressure and the cumulative water production of the reservoir.

8. A device for calculating the gas storage capacity of an aquifer gas storage reservoir for implementing the method for calculating the gas storage capacity of an aquifer gas storage reservoir according to claim 1, characterized in that: include: A module for determining the volume of water bodies in aquifer structures, which is used to obtain the data of the aquifer structure closure area, the thickness and effective porosity of the water-bearing reservoir, and the density of the aquifer water bodies, and determine the volume of water bodies in aquifer structures; A functional relationship determination module is used to obtain the gas reservoir pressure and cumulative water production data of the aquifer gas storage reservoir, and obtain the functional relationship between the cumulative water production and the pressure; The pore volume division module is used to divide the pore volume occupied by the dynamic reserves of the gas reservoir into three pore volumes: cumulative water production, water elastic compression, and rock pore expansion according to the material balance principle; A pore volume determination module, which determines the pore volume contributed by each pore volume to the dynamic reserves of the gas reservoir according to the pore volume occupied by the dynamic reserves of the gas reservoir; The gas storage capacity determination module determines the gas storage capacity according to the pore volume and dissolved gas volume of the gas stored in the gas storage reservoir.

9. The device for calculating the gas storage capacity of an aquifer gas storage reservoir according to claim 8, comprising a computer-readable storage medium, characterized in that: The computer readable storage medium stores a computer program, the computer program comprising an aquifer structure water volume determination module, a functional relationship determination module, a pore volume division module, a pore volume determination module and a gas storage capacity determination module; The computer program is used to run the method for calculating the gas storage capacity of an aquifer gas storage reservoir. When the computer program is executed by a processor, the method for calculating the gas storage capacity of an aquifer gas storage reservoir under set injection and production pressure conditions is implemented.

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