| 摘要 |
<p>A method for emplacing a production casing such as a pipeline or other conduit beneath a surface obstacle such as a water course is disclosed. A drill is provided which has a trailing drill string. A pilot hole is drilled along an inverted arcuate path beneath a surface obstacle from one side to the other side of the obstacle so that the drill string occupies the pilot hole. A reamer is provided which has a relatively smaller leading end and a larger trailing end. The leading end of the reamer is attached to one of the ends of the drill string, and an end of the production casing is attached to the trailing end of the reamer. The production casing is thrust into the pilot hole at one side of the surface obstacle to project the reamer with the production casing following into the pilot hole. As the production casing is thrust into the pilot hole at one side of the obstacle, the drill string exits the pilot hole at the opposite side of the obstacle. The reamer is operated by rotating the production casing or other method simultaneously with thrusting the production casing into the pilot hole to scarify and dislodge the earth circumscribing the pilot hole. The pilot hole is enlarged to a diameter slightly greater than the production casing to provide an annulus between the production casing and the reamed hole. Drilling mud is injected through the drill string to exit at the reamer where it entrains the dislodged earth. The drilling mud containing the dislodged earth is allowed to flow into the annulus surrounding the production casing.</p> |
