Sand charging device used during fracturing or slotting under coal mine and sand charging control method

Abstract

The invention discloses a sand charging device used during fracturing or slotting under a coal mine and a sand charging control method. The device comprises a water inlet pipe, a mixing pipe and a water outlet pipe which are sequentially connected, wherein a first electric valve, a first digital pressure meter, a first electromagnetic flowmeter are arranged on a pipeline of the water inlet pipe; an outlet end of the water outlet pipe is connected with a medium inlet of a medium booster pump; a check valve, a second digital pressure meter and a second electromagnetic flowmeter are arranged on a pipeline of the water outlet pipe; a hopper for accommodating sand is communicated with the upper part of the mixing pipe through a sand feeding pipe, and an electric unloading valve and an electric gate valve are arranged on a pipeline of the sand feeding pipe; the first electric valve, the electric unloading valve and the electric gate valve are anti-explosive; and the water inlet pipe, the mixing pipe and the water outlet pipe are respectively fixed on a flat mine vehicle. By the device, the sand charging time and sand charging amount are controlled by the conventional control technology. The sand charging device is simple in structure, small in size and safely used; and by the method, the coal seam cracking efficiency can be improved, and an anti-reflection effect of cracked coal and rock mass is guaranteed.

Description

technical field [0001] The invention relates to the technical field of underground coal seam gas drainage in coal mines, in particular to a sand adding device and a sand adding control method used in coal mine underground hydraulic fracturing or slotting processes. Background technique [0002] Coal seam gas is a kind of clean energy, but it is also a source of disaster for coal mine production. The geological conditions of coal occurrence in my country are complex, mainly relying on underground mining. With the increase of mining depth, the gas content of coal seams gradually increases, the pressure of coal seam gas increases, the risk of outburst increases, and the difficulty of outburst prevention becomes more and more difficult. With the increase of mining depth, the increasingly strong demand for resources, the introduction of a series of national mandatory measures on coal mine gas disaster control and the introduction of incentive policies for the development and util...

AI Technical Summary

Problems solved by technology

It has been found through practice that in the hydraulic cutting technology, pure water was used as the cutting medium in the past, but it often cannot achieve the expected cutting effect on the coal body with a large hardness coefficient and the rock on the roof and floor of the coal seam, and its cutting ability is limited. After adding a small amount of sand and gravel in the water, the coal rock mass with a large hardness coefficient can be cut through with a lower slotting pressure; the hydraulic fracturing technology of coal rock mass has a better effect on the permeability enhancement of coal rock mass, but After clear water fracturing is completed, the fractures generated by fracturing are easy to close, which reduces the effect of anti-permeability after fracturing. When a small amount of sand is added to the fracturing water, the sand that enters the fracture is used as a support to support the coal rock. The support function of the body to prevent the closure of the fractured fractures and ensure the anti-permeability effect after fracturing

However, there is no complete set of sanding equipment or devices available in the prior art, and there is even a lack of scientific sanding control methods. The amount of sanding can only be controlled by manually adjusting the opening and closing of the material gate through a simple sanding hopper. High strength, poor safety, unsatisfactory sand-water mixing ratio, and seriously restrict the efficiency and anti-permeability effect of hydraulic fracturing and slotting

Images