Drilling Technology of Variable-diameter Casing Protective Hole in Unstable Formation

Abstract

The invention discloses a drilling technology of variable-diameter casing protection holes in unstable formations, which can realize directional drilling of protection holes in unstable formations and solve problems such as hole collapse and diameter reduction in drilling in unstable formations. Under the effect of the hole protection function of the variable diameter casing, it avoids hole collapse and diameter shrinkage in the unstable formation hole section during subsequent drilling, and avoids the occurrence of drill sticking and drill drop accidents. The hole protection function of the casing 2 in the hole section of the unstable formation ensures the smoothness of the directional drilling channel and meets the needs of mine gas control and water damage prevention, and this method has good effect and strong stability during the construction process, and the unstable The formation protection hole has high drilling efficiency and good hole-forming performance.

Description

technical field [0001] The invention relates to the technical field of coal mine machinery construction technology, in particular to a drilling technology of variable-diameter casing protection holes in unstable formations. Background technique [0002] With the continuous improvement and application of underground directional drilling technology in coal mines, it is easy to encounter unstable formations when performing directional drilling underground in coal mines, such as structural formations, broken formations, soft formations, etc., and directional drilling in such formations is often Collapsing holes and shrinking diameters can easily cause drill drop and lead to large economic losses, reduce the hole formation rate of directional drilling, and block the drilling channels due to hole collapse and shrinkage, which will affect the effects of gas control and water damage prevention, and affect the safety of coal mines Efficient production will lead to mine safety acciden...

AI Technical Summary

Problems solved by technology

[0002] With the continuous improvement and application of underground directional drilling technology in coal mines, it is easy to encounter unstable formations when performing directional drilling underground in coal mines, such as structural formations, broken formations, soft formations, etc., and directional drilling in such formations is often Collapsing holes and shrinking diameters can easily cause drill drop and lead to large economic losses, reduce the hole formation rate of directional drilling, and block the drilling channels due to hole collapse and shrinkage, which will affect the effects of gas control and water damage prevention, and affect the safety of coal mines High-efficiency production, which will lead to mine safety accidents in severe cases

[0003] At present, there are few researches on the drilling technology of variable-diameter casing for hole protection in unstable underground coal mine formations, and there are no relatively mature products for large-scale industrial application. Only relevant technologies have been applied in the fields of petroleum and geological exploration and development, but due to The working environment, drill tool assembly, target stratum and process characteristics in the field of coal mine underground and surface oil drilling and geological exploration are quite different, which cannot meet the needs of coal mine directional drilling construction

[0004] Therefore, in order to solve the above problems, there is a need for an unstable formation variable-diameter casing protection hole drilling technology, which can realize the directional drilling of the protection hole in the unstable formation, and solve the problem of collapsed holes, shrinkage, etc. diameter and other issues

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