Injection production capability descending probability calculation method of salt cavern well for storing natural gas

Abstract

The invention discloses an injection production capability descending probability calculation method of a salt cavern well for storing natural gas, which is used for determining an injection production capability descending risk of the salt cavern well based on a fault tree method and judging the possibility that the injection production capability of the salt cavern well descends. According to the injection production capability descending probability calculation method disclosed by the invention, a fault tree of injection production capability descending of the salt cavern well is established; by adopting a history statistical method and an established engineering evaluation model, the basic event occurrence probability of causing injection production capability descending of the salt cavern well is determined, and the influence actions of various risk factors to the basic event occurrence probability is led into basic event probability calculation in a mode of correction factors; and meanwhile, according to the logic of the fault tree, the injection production capability descending probability calculation method of the salt cavern well in four influence modes including smaller running slowdown, larger running slowdown, temporary interruption and long-term interruption is established, one key problem of failure probability calculation in salt cavern well risk evaluation is solved, and the technical basis can be supplied for controlling and preventing injection production capability descending risks of the salt cavern well to a gas storage manager.

Description

technical field [0001] The invention relates to the technical field of integrity management of salt cavern type natural gas underground gas storage, in particular to a method for calculating the decline probability of injection and production capacity of salt cavern wells storing natural gas. Background technique [0002] Salt cavern well is an underground gas storage facility that injects gas into abandoned salt caverns or salt caverns built by water solution on salt domes or salt layers through the wellbore, and can be extracted to meet market demand (such as figure 1 As shown, 1 is the wellhead, 2 is the surface casing, 3 is the production casing, 4 is the annular protection fluid, 5 is the downhole safety valve, 6-injection production pipe, 7 is the packer 8-casing shoe 9 - Natural gas 10 - Residual brine). Considering the flammable and explosive characteristics of natural gas and the functional requirements of salt cavern wells for safe gas supply to users, salt cavern...

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Problems solved by technology

However, there is still no specific report on the risk assessment of injection-production capacity decline

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