Method for developing low-permeability gas reservoir

Abstract

The invention discloses a method for developing a low-permeability gas reservoir, which comprises the following steps: positioning a drilling ship on a sea for well drilling and well completion, establishing a synthetic natural gas migration channel between a production gas reservoir sand body of a developed gas field and a selected to-be-developed low-permeability gas reservoir and combining with a fracturing technology; utilizing the production gas reservoir sand body as a transporting layer and fully utilizing a production platform of the developed gas field or the existing well network of the production gas reservoir of an underwater production system to realize the development of the developed gas field on the sea or the low-permeability gas reservoir on the periphery of the developed gas field so as to reduce the well drilling quantity and the well completion period and reduce the well drilling and well completion expenses. The method has the benefits that well drilling and well completion operation procedures and a well completion tube string structure are simplified, the operation difficulty and the workload are reduced, and the cost is greatly reduced; and by adopting the method, a residual well slot or a residual underwater wellhead is not required, a well slot or a underwater wellhead is not required to be additionally arranged, and a production platform or a underwater production system is not required to be newly built, so that the development investment is greatly reduced, and the economic benefit is greatly improved.

Description

technical field [0001] The invention relates to a method for developing natural gas, in particular to a method for developing low-permeability gas reservoirs. Background technique [0002] The patent belongs to the field of oil and gas development. Low-permeability gas reservoirs refer to gas reservoirs with poor reservoir physical properties and difficult to effectively develop on a large scale by conventional mining methods. There are currently many versions of the basis and standards for the division of low-permeability gas reservoirs. The domestically recognized one is based on the permeability. According to the classification, the gas reservoirs with permeability less than 10mD are classified as low-permeability gas reservoirs, and at the same time, low-permeability gas reservoirs are further divided into general low-permeability gas reservoirs, low-permeability gas reservoirs and ultra-low-permeability gas reservoirs. At present, there are three main methods for t...

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Problems solved by technology

[0004] 1) Drilling and development of new production platforms or underwater production systems. From the construction of new production platforms or underwater production systems to production, the cycle is long and the investment is large. It is difficult to achieve economical and effective low-permeability gas reservoirs in or around the developed offshore gas fields. At the same time, it will also cause the existing well pattern and existing production facilities of the developed gas field production platform or subsea production system to be unavailable

[0005] 2) The drilling and completion costs and engineering costs caused by the intensified well pattern greatly increase the development cost. In addition, the single-well production of low-permeability gas reservoirs is generally low and the economy itself is poor. It is difficult to realize the economical efficiency of low-permeability gas reservoirs. effective development

[0006] 3) There are no remaining well slots on the production platform of the developed gas field or no remaining underwater wellheads in the underwater production system, and it is impossible to add well slots or increase underwater wellheads, or directly drill from the established production platform or underwater production system. If it cannot be realized due to economic and technical reasons, the reserves of low-permeability gas reservoirs to be developed will not be developed, and the country's precious natural gas resources will be wasted

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