Application of directional sidetracking technology inside casing in Shengli petroliferous province;

After that,an isotropic undercutting process for forming the upper control electrodes and contact bar under the bridge.

The system is constructed by drilling method and the air intake and the gas outlet are connected by a directional drilling hole.

As a trenchless construction method, directional drilling and PE pipe dragging is uniquely advantageous, with less impact on nearby buildings and traffic, lower cost for maintenance, better protection of the ground services, etc.

Spiral and round curve methods of General Geological Coordinate System have established the basis on which the design of curved or directional drilling can be well calculated .

The article mainly discusses the cause of ramp-hole and its blights,introduces the prevention and treatment measures,and brings forward some suggestions to guarantee the drilling direction.