Marine gas hydrate and mortar replacement exploitation method and device

Abstract

The invention discloses a marine gas hydrate and mortar replacement exploitation method and device. According to the exploitation method, the sand blocking accuracy of a mechanical screen pipe is properly lowered to enable stratum mud and sand fine particles to flow into a shaft production pipe column and be discharged under the controllable condition, in the meantime, coarse-particle mortar is injected into a hydrate reservoir continuously, and through matching of a hydrate reservoir sand outlet management technology and mortar injection technology, replacement of the coarse-particle mortar and the stratum fine particles as well as the coarse-particle mortar and a hydrate space is achieved. The exploitation device comprises a production sleeve pipe, a production oil pipe, a shaft water injection pipe and a mortar back-injection pipe, the lower end of the production sleeve pipe is connected with the mechanical screen pipe, and the upper end and the lower end in the mechanical screen pipe are further provided with an upper mechanical packer and a lower mechanical packer correspondingly. The inlet end of the production oil pipe is provided with a gas separating device, and the position, above the upper mechanical packer, of the shaft water injection pipe communicates with the production oil pipe. The mortar back-injection pipe penetrates through the upper mechanical packer and the lower mechanical packer, extends to the bottom border of the production layer section of the hydrate reservoir and is connected with a gravel filling tool. Through the method and the device, the purpose of continuous and efficient production is achieved.

Description

technical field [0001] The invention belongs to the field of high-efficiency exploitation of marine natural gas hydrates, and in particular relates to a mortar replacement mining method and a mining device for natural gas hydrates in sea areas, which are suitable for mining by the depressurization method or formation fluid extraction method. Background technique [0002] Gas hydrate is a kind of energy that has existed stably for millions of years and has huge reserves. More than 90% of the gas hydrate resources are stored in deep-sea shallow sediments. Strong research interests. If the natural gas hydrates in the surrounding seas of my country can be exploited safely and effectively, it will greatly promote the improvement of my country's energy structure. In 2017, my country's first sea area natural gas hydrate trial production project hosted by the China Geological Survey achieved a historic breakthrough of continuous drainage for 60 days and an average daily gas product...

AI Technical Summary

Problems solved by technology

[0006] To sum up, the process of gas hydrate decomposition from solid phase to gas and water two-phase production will lead to formation deficit, and the production of formation mud and sand will further aggravate the large-area deficit in the hydrate decomposition area around the wellbore, which has a negative impact on formation stability. Extremely unfavorable

CO 2 The displacement method cannot meet the demand for replacing the above-mentioned shortfall space and will cause a decrease in the seepage capacity of the formation near the wellbore

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