Method for mining hydrate based on multilateral wells

Abstract

A method for mining hydrate based on multilateral wells is provided. The method includes the following steps: deploying a vertical well in a target measure area and two horizontal multilateral wells in a natural gas hydrate reservoir, wherein one of the horizontal multilateral wells is deployed at the upper third of the natural gas hydrate reservoir, and the other horizontal multilateral well is deployed at the lower third of the gas hydrate reservoir; installing a gas-water separation device and a pump at the junction of the vertical well and the lower third horizontal well; deploying the vertical well to the top of a high-temperature and high-pressure water-bearing gas reservoir; performing perforation to open the high-temperature and high-pressure water-bearing gas reservoir and the hydrate reservoir; separating the mined mixture into natural gas and high-temperature water by the gas-water separation device, wherein separated natural gas enters an oil pipe and the high-temperature water is pumped into a hydrate reservoir by the gas-water separation device; at the same time, mining the hydrate reservoir in horizontal wells located at the upper third of the natural gas hydrate reservoir, and mining horizontal well groups of the hydrate reservoir by injecting high-temperature water under the formation of the natural gas hydrate reservoir. According to the present invention, thenatural gas hydrate reservoir is mined by heating and depressurizing, thereby achieving the cyclic utilization of formation energy.

Description

technical field [0001] The invention relates to a method for joint exploitation of high-temperature and high-pressure gas reservoirs and hydrate reservoirs, which is applied in the field of natural gas hydrate exploitation. Background technique [0002] As clean energy with abundant reserves, geothermal energy and hydrate have attracted widespread attention from various countries. Among them, geothermal energy generally refers to the energy released by the earth. According to the properties of heat storage bodies, geothermal energy can be divided into hydrothermal, enhanced and shallow geothermal energy resources. Hydrates are currently distributed in deep-sea sediments or permafrost in land areas. They are ice-like crystalline substances formed by natural gas and water under high-pressure and low-temperature conditions. At present, the proposed exploitation of marine natural gas hydrate mainly includes thermal shock mining method, depressurization mining method, and chemic...

AI Technical Summary

Problems solved by technology

The present invention adopts the separation and same well injection-production mining method to mine hydrate reservoirs, which can accelerate the hydrate mining speed, enable hydrates to be exploited in large quantities, and at the same time make up for the low utilization rate of thermal stimulation and high development costs in traditional mining methods. question

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