Coal mine downhole hydraulic fracturing high-pressure sealing continuous aggregate adding system and method

Abstract

The invention provides a coal mine downhole hydraulic fracturing high-pressure sealing continuous aggregate adding system and method. The coal mine downhole hydraulic fracturing high-pressure sealingcontinuous aggregate adding system comprises at least one aggregate adding device, a high-pressure fracturing pump group and a pneumatic aggregate feeding tank. The pneumatic aggregate feeding tank isconnected to the aggregate adding device and can provide aggregate simultaneously. The pneumatic aggregate feeding tank further provides the aggregate in the aggregate feeding tank to a sand mixing system quantitatively at a fixed speed through a downhole air supply system. The high-pressure fracturing pump group is connected to the aggregate adding device to provide pressure. The aggregate adding device is connected to a fracturing hole in a coal seam of a fracturing object, and the continuous work of sand fracturing is realized in an alternate transmission mode. Therefore, high-pressure fracturing fluid is supplied by a large displacement and high-pressure fracturing pump group in the front-end downhole during the construction process, and is conveyed by two ways through high-pressure resistant pipes, the mixed power of aggregate and fracturing fluid is provided in one way; the other way enters an aggregate mixing chamber and is mixed with the aggregate, so that it is guaranteed that the fracturing fluid and the aggregate are evenly mixed, and the mixture ratio of the aggregate and fracturing is ensured.

Description

technical field [0001] The invention relates to the technical field of coal mine hydraulic fracturing enhanced drainage, in particular to a coal mine hydraulic fracturing high-pressure continuous aggregate adding system and method, the device and method through the front-end underground large displacement, high The pressure fracturing pump unit supplies high-pressure fracturing fluid, which is transported in two ways by using a high-pressure resistant pipe. One way provides mixed power for aggregate and fracturing fluid; the other way enters the aggregate mixing room and is mixed with aggregate, which ensures The fracturing fluid and aggregate are evenly mixed, and the mixing ratio of aggregate and fracturing is ensured. Background technique [0002] my country is one of the countries with the most serious coal mine gas disasters in the world. With the continuous increase of coal mining depth, the characteristics of coal seam softness, low permeability, high gas content, hig...

AI Technical Summary

Problems solved by technology

The existing underground hydraulic fracturing anti-permeability technology in coal mines mainly focuses on clear water fracturing and the application of non-fracture proppant. The gas migration and fracture channels formed by fracturing are reduced or even completely sealed under the action of formation closure pressure, which affects the anti-permeability effect of coal seams.

Some scholars and researchers have carried out the exploration of downhole sand fracturing devices and anti-permeability technology, but limited by the function of the device, there are overall problems such as small amount of sand added at one time, uneven sand mixing, long interval time of sand addition, and small sand particles. , resulting in a significant decrease in the pressure in the fracturing borehole, a decrease in the sand-carrying flow rate of the fracturing fluid, a small radius of the fracturing support in the borehole, and no obvious anti-reflection effect.

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