Multi-branch hydrate displacement mining method

Abstract

The invention discloses a multi-branch hydrate displacement mining method. A mining well is drilled in a hydrate reservoir in the horizontal direction, so that the situation that a large number of resources are repeatedly consumed to penetrate through a compact overlying layer of hydrate is avoided; initial mining is conducted, pressure reduction mining is conducted on the horizontal mining well through a pressure reduction means, then fracturing and soaking pressure building are conducted on the horizontal mining well through a displacement substance, so that the displacement substance makes full contact with and reacts with the hydrate; and meanwhile, a next horizontal mining well is drilled in the same-layer deflection position or the upper-layer position of the horizontal mining well, hydrate mining can be conducted in other positions while displacement operation is achieved, thus mining and displacement are conducted simultaneously, the time cost needed by displacement operation is saved, a plurality of layers of branch wells in the vertical depth direction and the plane direction can exist simultaneously, the combination form of the branch wells is not limited, and hydrate displacement mining of the whole reservoir is effectively achieved only by fully considering the factors such as the thickness and range of the mined hydrate reservoir, the geological characteristics and the drilling and mining process safety.

Description

technical field [0001] The invention relates to the technical field of hydrate mining, in particular to a multi-branch hydrate replacement mining method. Background technique [0002] Hydrate is a clathrate unit cell compound formed by natural gas water under low temperature and high pressure environment, which is mainly distributed in terrestrial permafrost and seabed sediments. The current hydrate production methods mainly include depressurization method, heat injection method, chemical inhibitor injection method, displacement method and solid-state fluidization method. Among them, the depressurization method controls the decomposition efficiency of hydrate by adjusting the pressure. The expensive excitation process is recognized as the most economical mining method at present; the heat injection method increases the temperature of the reservoir by injecting heat to heat the formation, and then realizes the decomposition of hydrates, but the thermal conductivity is very lo...

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Problems solved by technology

[0005] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a multi-branch hydrate displacement production method, which can solve the problem of high cost, limited single well productivity and easy large-scale formation instability in the existing hydrate production method. And other issues

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