coring operation in coal seams is very difficult as they are very loose.
煤层颗粒疏松、巖心成柱性差,给取心工作带来了极大困难。
diamond core bit is preferred for coring operation in terms of the special requirements of scientific drilling.
根据科学鉆探对巖心的特殊要求,认为金刚石取心鉆头是科学深鉆取心鉆进较理想的选择。
the quick latch jack can be widely used in the coring operation in the oil and gas drilling engineering.
本实用新型可广泛用于石油、天然气鉆井工程取巖心作业中。