The core drilling method and the obtained achievement are introduced with respect to the bit and core barrel used in different formation.
根据不同地层所采用的钻头和取心器，介绍了不同地层的钻进取心方法和取得的成果。
Objective:To introduce a new prefabricated post-and -core system, a helical drilling bit and a prefabricated post-and -core consisting of a root canal orifice bur which was designed by the author.
目的：介绍一种由螺旋型根管钻、自行设计的根管口台阶状车针、预成桩核组成的预成桩核系统。
Diamond core bit is preferred for coring operation in terms of the special requirements of scientific drilling.
根据科学钻探对岩心的特殊要求，认为金刚石取心钻头是科学深钻取心钻进较理想的选择。
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