Method for promoting vertical shaft shale gas exploitation through horizontal multilateral well burning explosion fracturing

Abstract

The invention discloses a method for promoting vertical shaft shale gas exploitation through horizontal multilateral well burning explosion fracturing. The method comprises the following steps that firstly, a vertical shaft and a plurality of horizontal multilateral wells are arranged, then a first burning explosion hole packer is mounted in one of the horizontal multilateral wells, and a hole sealing section is formed between the first burning explosion hole packer and the deepest part of the horizontal multilateral well; and when blast fracturing is carried out, blast gas is injected into the hole sealing section, real-time detection is carried out through a detection device, injection of the blast gas is stopped until a value required by explosion is reached, finally an ignition head is controlled to ignite, so that the blast gas in the hole sealing section is triggered to explode, high-temperature and high-pressure gas and detonation shock waves generated by gas explosion are generated, the surrounding shale is subjected to one-time impact fracturing process through meshes in a screen pipe, the process is repeated for multiple times, and a fracture network is formed around the horizontal multilateral wells through retreating type fire blast fracturing; and therefore, a complex fracture network can be generated in the reservoir without a water source, and meanwhile, the fracture network can keep connectivity for a long time, so that extraction of shale gas is guaranteed.

Description

Technical field [0001] The present invention relates to a method of horizontal branch well fracturing fracturing promoting shaft shale gas mining, belonging to the field of shale gas mining technology. Background technique [0002] The current shale gas is considered to be the most expected replacement of coal. However, due to the depth of the shale reservoir, the penetration rate is low, and therefore manual methods are required to promote the development of the reservoir, and increase shale gas production. Hydro-hydraulic fracturing of horizontal wells is the most important method, but the yield of the shale gas well can be reached halfway after the reservoir fracturing. The main reason is that the hydraulic fracturing time is longer, so the fracture environment is affected during the fracturing process, and the crack extension is difficult to form a complex fracture network, and the proppant is difficult to enter the micro-crack, so that the fracture fracture stress is stress....

AI Technical Summary

Problems solved by technology

However, due to the deep burial and low permeability of shale reservoirs, artificial methods are needed to promote the development of reservoir fractures and increase shale gas production

Staged hydraulic fracturing of horizontal wells is currently the most important method, but the production of shale gas wells can be reduced by half after reservoir fracturing

The main reason is that the hydraulic fracturing takes a long time, so affected by the stress environment during the fracturing process, it is difficult to form a complex fracture network due to single fracture expansion, and it is difficult for proppant to enter the micro-fractures, so that the fractured fractures are re-opened under the action of in-situ stress. closure

In addition, in water-scarce areas, shale reservoirs with high clay mineral content are not suitable for hydraulic fracturing methods, and the construction of long-distance horizontal wells greatly increases the economic cost.

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