Advanced Techniques for Drilling 1,000-Ft. Small Diameter Horizontal Holes in a Coal Seam. Volume 1.

摘要

This report discusses the various factors that affect the directional control of holes being drilled horizontally into coalbeds,describes the evaluation of various devices and techniques for controlling the hole direction,and indicates a method of guiding the bit through the coalbed. Deeper mines (1,500to 2,500ft) are the current trend in the coal industry,and with increased depth has come increased hazards. One significant problem is the elimination of uncontrolled methane emissions,which increase with depth. The Bureau of Mines immediate effort is toward the prevention of disastrous explosions,but the ultimate goal is to provide the technology needed to predrain the methane far in advance of active mining. This study has resulted in the development of devices and techniques that can be used to consistently drill horizontal holes in a coal seam to 1,000ft and with 30ft of the original bearing line.