Multiple-interlayer salt cavern gas storage and building method of multiple-interlayer salt cavern gas storage

Abstract

The invention belongs to the field of oil and gas resource development and particularly relates to a multiple-interlayer salt cavern gas storage and a building method of the multiple-interlayer salt cavern gas storage. The multiple-interlayer salt cavern gas storage comprises a salt cavern and a natural gas injection-production string system, wherein the natural gas injection-production string system is connected with the top of the salt cavern. Top mud rocks, multiple-interlayer salt rocks and bottom mud rocks are sequentially arranged downwards from the ground. The multiple-interlayer salt rocks are composed of salt rocks and interlayers which alternately appear. The multiple-interlayer salt cavern gas storage is characterized in that the salt cavern is positioned in the multiple-interlayer salt rocks; a first salt rock layer, the interlayer and a second salt rock layer are sequentially arranged from the bottom of the top mud rocks to the top of the salt cavern; and the top of the salt cavern is in the shape of circular plane. The building method of the multiple-interlayer salt cavern gas storage comprises the following steps of: selecting top structure, drilling a well, completing the well, installing the injection-production string, carrying out solution mining, and controlling the size of the top structure. According to the building method, the characteristics of the top structure of the multiple-interlayer salt cavern gas storage are mainly considered, the parameters of the size of the top structure are provided, the operability is strong, and the cost is not obviously increased. The building method is good in popularization.

Description

technical field [0001] The invention belongs to the field of oil and gas resource development, and in particular relates to a multi-interlayer salt cavern gas storage and a construction method thereof. Background technique [0002] The height of the salt-cavern gas storage in the multi-interlayered salt rock formation mainly depends on the thickness of the salt rock, which is much smaller than the height of the gas storage in the salt dome type. In order to ensure the volume of the salt cavern gas storage, it is necessary to increase the diameter of the salt cavern, so that the top salt layer and interlayer bear more self-weight, resulting in the stability of the top of the salt cavern in the multi-interlayer formation and the gas storage in the salt dome type formation. Significantly lower than that. At the same time, due to the small thickness and low strength of each layer of multi-interlayer salt rock, the possibility of instability of the gas storage is exacerbated. I...

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Problems solved by technology

In order to ensure the volume of the salt cavern gas storage, it is necessary to increase the diameter of the salt cavern, so that the top salt layer and interlayer bear more self-weight, resulting in the stability of the top of the salt cavern in the multi-interlayer formation and the gas storage in the salt dome type formation. Significantly lower than

At the same time, due to the small thickness and low strength of each layer of multi-layered salt rock, the possibility of instability of the gas storage is exacerbated.

In the existing technology, in the design process of the top of the salt cavern gas storage, the top of the salt cavern gas storage is often designed as a pressure arch structure with good stability. In fact, the interlayers (anhydrite layer, mud-salt layer and Glauberite layers, etc.) dissolve in water much faster than salt rocks, resulting in a relatively flat top structure rather than an arched structure at the top of the salt cavern gas storage

However, the influence of this factor was not taken into account in the design, which greatly reduced the stability of the top structure of the multi-interlayer salt cavern gas storage, and even collapsed

At home and abroad, there have been researches on the design of the top structure of multi-interlayer salt-cavern gas storage, but no specific technical parameters that can be used for actual operation have been given, which cannot guide the construction of multi-interlayer salt-cavern gas storage in my country

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