Underground salt cavern gas storage and building method thereof

Abstract

The invention belongs to the field of development of oil and gas resources, and particularly relates to an underground salt cavern gas storage and a building method thereof. The underground salt cavern gas storage comprises a salt cavern, a guide tube, a technical casing, a well completion casing, a control valve, a pressure gauge, a packer, slips, a sealing cover and a natural gas injection and extraction tubular column; the natural gas injection and extraction tubular column penetrates into the underground salt cavern from the ground; the well completion casing penetrates into the top of the underground salt cavern form the ground; the bottom end of the well completion casing is connected with the natural gas injection and extraction tubular column via the packer and the slips; the sealing cover, the pressure gauge and the control valve are mounted at the position of a wellhead; and steel grade of the well completion casing in the stratum of the salt cavern is higher than that of a well completion casing in another stratum by a grade. Construction steps include selecting external collapse load; determining model selection of the tubular column and penetration depth; drilling andcementing a well; mounting the packer and the slips; mounting the sealing cover; and mounting the pressure gauge and the control valve. Influence of salt rock creep to safety of the well completion casing is emphasized, simultaneously, the sealing performance of the tubular column is monitored in real time, and safety and reliability are high.

Description

technical field [0001] The invention belongs to the field of oil and gas resource development, and in particular relates to an underground salt cavern gas storage and a construction method thereof. Background technique [0002] Due to the fact that salt rock in my country has many salt rock layers, thin thickness, and interlayers appear alternately, the safety of completion casing strings in underground salt-cavern gas storages faces greater challenges. There are three main reasons: first, because salt rock has typical creeping Under the action of far-site stress, the salt rock near the wellbore begins to creep, causing displacement and deformation around the wellbore, so that the ground stress acts on the cement sheath and completion casing through the salt rock creep, and the extrusion load shows Great unevenness. Second, the physical and mechanical properties of the interlayer and salt rock are quite different, and they show strong deformation inconsistency during creep de...

AI Technical Summary

Problems solved by technology

[0003] (1) The existing patents on oil and gas well completion pipes are mainly aimed at oil and gas reservoirs, without considering the actual working conditions and stress characteristics of salt-cavern gas storage. If applied to the completion pipe string of salt-cavern gas storage, it will There will be safety hazards

[0004] (2) In the design of the casing in the salt rock formation, the force of the casing in the salt rock formation is used as the design basis, which often makes the safety redundancy of the casing string in the upper formation higher, resulting in waste

[0005] (3) The influence of high-pressure gas in the pipe string is not considered in the design process of the casing string in the salt rock formation, and the natural gas leakage monitoring and control device is not installed, so the safety and reliability are low

Images