Frozen soil layer natural gas hydrate horizontal branch well pattern mining system and method

Abstract

The invention discloses a frozen soil layer natural gas hydrate horizontal branch well pattern mining system and method. The system comprises a main drilling well, a production area, a production well, an area multi-branch well, a production area boundary, a filling body, a decomposition enhancement area, a main drilling well horizontal section, a main drilling well vertical section, a branch well, a decomposition circle and an arch structure. The multi-branch well pattern has the beneficial effects that the multi-branch well pattern can improve the pressure sensitivity of formation fluid andprovide more decomposition free surfaces for natural gas hydrates; after mining is finished, grouting operation is carried out to fill cavities and through cracks formed after mining, the rock stratumarch structure is enhanced, potential environment damage risks are reduced, and the division of production areas and the succession order between the production areas in the long-term production process are planned.

Description

technical field [0001] The invention relates to a method for exploiting natural gas hydrate in permafrost layers, in particular to a horizontal branch well pattern exploitation system and method for natural gas hydrate in permafrost layers, belonging to the technical field of energy exploitation. Background technique [0002] In the past ten years, my country has successively carried out several gas hydrate test productions in the permafrost area of ​​Qilian Mountains and the Shenhu Sea Area, especially the trial production in the Shenhu Sea Area broke the records of other countries. But at the same time, whether the test production was terminated passively due to an accident or voluntarily ended, it shows that there is still a certain distance from the commercialization of natural gas hydrate production. The main factors restricting the development of natural gas hydrates are environmental problems and long-term production system layout problems. [0003] At present, the m...

AI Technical Summary

Problems solved by technology

However, goafs will be formed after mining, resulting in ground subsidence areas, leading to the degradation of permafrost. Even if there is no obvious subsidence, cracks connecting the surface and the reservoir may be formed, which will cause the reservoir to continuously decompose natural gas directly into the atmosphere, aggravating The Greenhouse Effect and Changes in Global Temperature

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