CN-122014345-A - Method for building and operating aquifer gas storage

CN122014345ACN 122014345 ACN122014345 ACN 122014345ACN-122014345-A

Abstract

The invention discloses a method for constructing and operating an aquifer gas storage, which comprises the following steps of S1, carrying out an in-situ blasting fracturing strategy on a selected aquifer to form a reservoir space containing a fracture network and a cavity in the selected aquifer, S2, controlling reaction conditions of the in-situ blasting fracturing strategy to enable non-combustible gas to remain in the reservoir space after reaction is finished as bottom filling gas of the gas storage, S3, carrying out periodic gas injection and production operation on the reservoir space, thereby actively creating the reservoir space and regulating and controlling the reaction to generate self-generated bottom filling gas through in-situ blasting fracturing, and solving the problems of long period and high initial investment cost caused by outsourcing and injection of a large amount of bottom filling gas due to slow gas injection and water driving in the conventional aquifer construction.

Inventors

CAI CHENGZHENG
GAO YUPENG
ZHOU ZHI
GAO YANAN
WU HANQI
ZHOU YUEJIN
Zou Zengxin
LI JIACHENG

Assignees

中国矿业大学
中国石油天然气股份有限公司储气库分公司

Dates

Publication Date: 20260512
Application Date: 20260310

Claims (10)

1. The method for constructing and operating the aquifer gas storage is characterized by comprising the following steps: S1, carrying out in-situ blasting fracturing on a selected aquifer (5) to form a reservoir space containing a fracture network (7) and a cavity in the selected aquifer (5); S2, controlling the reaction conditions of the in-situ blasting fracturing to enable non-combustible gas to remain in the reservoir space after the reaction is finished to serve as bottom gas of the gas storage; s3, carrying out periodic injection and production operation of natural gas on the storage space.
2. The method for constructing and operating an aquifer gas storage according to claim 1, wherein in step S1, the in-situ blasting fracturing comprises the steps of: The detonation is performed by injecting a mixed gas of fuel gas and combustion-supporting gas into a target interval in the aquifer (5) and by an ignition electrode (8).
3. The method for constructing and operating an aquifer gas storage according to claim 2, wherein in step S2, the controlling the reaction conditions of the in-situ combustion fracturing comprises the steps of: And controlling the mixing ratio of the fuel gas and the combustion-supporting gas to ensure that the gas reserved in the storage space after the explosion reaction contains carbon dioxide.
4. A method of constructing and operating an aquifer gas storage as claimed in claim 3 wherein the fuel gas is methane and the combustion supporting gas is oxygen and the mixing volume ratio of methane to oxygen is in a fuel rich state.
5. The method for constructing and operating an aquifer gas storage according to claim 4, further comprising a step of soaking after step S1 and before step S3: and closing the wellhead after the explosion reaction is finished, so that the well bore (3) and the reservoir space system are kept in a closed state for a preset time under the underground environment temperature and pressure.
6. A method of constructing and operating an aquifer gas storage as claimed in claim 5 wherein the duration of the step of soaking is determined from the temperature and pressure recovery profile of the aquifer (5).
7. The method for constructing and operating an aquifer gas storage according to claim 1, wherein step S3 further comprises the steps of: during the gas injection phase of the first gas injection cycle, the peak gas injection pressure applied approaches, but does not exceed, the fracture pressure of the reservoir space formed by the in situ combustion and explosion fracturing described in step S1.
8. A method of constructing and operating an aquifer gas storage according to any one of claims 1 to 7, further comprising step S4, during or after the execution of step S3: one or more additional in situ combustion fracturing is performed at a new location within the aquifer (5) based on the monitoring of the reservoir space morphology and gas migration.
9. A method of constructing and operating an aquifer gas storage as claimed in claim 8 wherein said additional in situ explosive fracturing is carried out in a sequential manner at planned boundaries or in a storage area of said gas storage.
10. A method of constructing and operating an aquifer gas storage as claimed in claim 8 wherein said monitoring comprises at least one of microseismic monitoring, tracer monitoring or wellbore (3) pressure monitoring.

Description

Method for building and operating aquifer gas storage Technical Field The invention relates to the technical field of underground energy storage, in particular to a method for constructing and operating an aquifer gas storage. Background The underground gas storage is an indispensable peak regulation and supply protection facility in a natural gas transportation and distribution system and mainly comprises four types of gas reservoirs, salt caverns, water-bearing layers and pits. Wherein the water-bearing layer type underground gas storage is an artificial gas reservoir formed by injecting natural gas into an underground water-bearing reservoir with good sealing conditions through high pressure and displacing pore water through gas injection. However, the conventional aquifer gas storage construction process is generally time-consuming and costly. The natural gas is continuously injected into a natural water-bearing layer, and a gas cap with a certain scale is gradually formed through long-time displacement. This process not only takes years or even longer to reach the designed reservoir capacity, but also requires the injection of large amounts of expensive natural gas as "bottom gas" to maintain reservoir pressure and prevent water intrusion. The part of bottom gas cannot be extracted in the whole life cycle of the gas storage, and huge sinking cost is formed. In addition, the permeability of natural aquifers is generally limited, so that the gas injection and production rate is low, and the rapid peak regulation requirement in peak time is difficult to meet. Under the background, an innovative construction and operation method of the aquifer gas storage is to be developed, and the method aims to overcome the defects of long period, high cost and low efficiency of the traditional construction mode. Disclosure of Invention The invention solves the technical problems that the traditional method depends on a slow gas injection and water driving process, can not quickly respond to the emergency peak regulation capability, and needs to outsource a large amount of natural gas injection and permanently seal underground, thus occupying huge funds and being unable to recycle. In order to solve the technical problems, the invention provides the following technical scheme: the construction and operation method of the aquifer gas storage comprises the following steps: s1, carrying out in-situ blasting fracturing on a selected aquifer, and forming a reservoir space containing a fracture network and a cavity in the selected aquifer; S2, controlling the reaction conditions of the in-situ blasting fracturing to enable non-combustible gas to remain in the reservoir space after the reaction is finished to serve as bottom gas of the gas storage; s3, carrying out periodic injection and production operation of natural gas on the storage space. Preferably, in step S1, the in-situ blasting fracturing includes the following steps: And (3) injecting a mixed gas of fuel gas and combustion-supporting gas into a target interval in the aquifer, and performing deflagration through an ignition electrode. Preferably, in step S2, the controlling the reaction conditions of the in-situ combustion-explosion fracturing includes the following steps: And controlling the mixing ratio of the fuel gas and the combustion-supporting gas to ensure that the gas reserved in the storage space after the explosion reaction contains carbon dioxide. Preferably, the fuel gas is methane, the combustion-supporting gas is oxygen, and the mixing volume ratio of methane and oxygen is in a fuel-rich state. Preferably, after step S1 and before step S3, the method further comprises a step of soaking: And closing the wellhead after the explosion reaction is finished, so that the wellbore and the reservoir space system are kept in a closed state for a preset time under the underground environment temperature and pressure. Preferably, the duration of the step of soaking is determined from the temperature and pressure recovery profile of the aquifer. Preferably, the step S3 further includes the following steps: during the gas injection phase of the first gas injection cycle, the peak gas injection pressure applied approaches, but does not exceed, the fracture pressure of the reservoir space formed by the in situ combustion and explosion fracturing described in step S1. Preferably, during or after the execution of step S3, step S4 is further included: And performing one or more additional in-situ combustion burst fractures at new locations within the aqueous layer based on the monitoring of the reservoir space morphology and gas migration. Preferably, the additional in situ combustion fracturing is performed in a sequential manner at planned boundaries or within a reservoir region of the gas reservoir. Preferably, the monitoring includes at least one of microseismic monitoring, tracer monitoring, or wellbore pressure monitoring. The invention has the beneficial effects