Installing method for collapse prevention pipe of horizontal well section of mining area L-shaped ground well

Abstract

The invention relates to an installing method for a collapse prevention pipe of a horizontal well section of a mining area L-shaped ground well and belongs to the field of mining area L-shaped groundwell coal bed gas extraction. At least one collapse prevention pipe unit and a variable diameter pup joint are provided, and ventilation holes are formed in the collapse prevention pipe units. The method comprises the following steps of calculation, wherein the number of the collapse prevention pipe units is calculated according to the length of the horizontal well section; pipe lowering, whereinthe collapse prevention pipe units and the variable diameter pup joint are lowered into the well in sequence through a drilling machine; separation, wherein a drill rod is rotated in the connecting thread loosening direction, and connecting threads on the variable diameter pup joint and the collapse prevention pipe units are separated; and lifting, wherein the separated variable diameter pup jointis lifted to the surface of the ground along with the drill rod. By means of the installing method, rock debris of collapse holes of the horizontal section of the mining area L-shaped ground well canbe supported to prevent hole blocking, the conical collapse prevention pipe can reduce the resistance when a collapse prevention pipe body enters the horizontal well section, and the rock debris in the horizontal well section is contained by a gap at a circular truncated cone and the tail end of the horizontal well section.

Description

technical field [0001] The invention belongs to the field of coalbed methane (gas) extraction in an L-shaped ground well in a mining area, and relates to a method for installing an anti-collapse pipe in a horizontal well section of an L-shaped ground well in a mining area. Background technique [0002] L-shaped surface wells in the mining area include arc-shaped wells and horizontal wells. The horizontal wells of the L-shaped surface wells in the mining area are usually arranged with open wells (holes). Due to the gravity of the overlying rock in coal mining, the horizontal wells are prone to hole collapse. , blocking holes and other phenomena that affect the gas drainage of surface wells. At present, the method of flushing the well (hole) with pressure water, which is often used to deal with the problem of collapsed or blocked holes, may not be able to play a good role. If the cuttings in the hole are not cleaned well, it will cause gas in the coal mining face and the upper...

AI Technical Summary

Problems solved by technology

[0002] The L-shaped surface well in the mining area includes arc-shaped well sections and horizontal well sections. The horizontal well section of the L-shaped surface well in the mining area is usually arranged with open wells (holes). Due to the gravity of the overlying rock in coal mining, the horizontal well section is prone to hole collapse , blocking holes and other phenomena that affect the gas drainage of surface wells

At present, the method of flushing the well (hole) with pressure water, which is often used to deal with the problem of collapsed or blocked holes, may not be able to play a good role. If the cuttings in the hole are not cleaned well, it will cause gas in the coal mining face and the upper corner. The drainage effect is greatly affected, and the L-shaped surface well coalbed methane (gas) drainage technology in the mining area is a practical technology for underground gas control

Images