To drill soft, unconsolidated, usually shallow formations by eroding the "rock" below the bit by hydraulic impact loading alone.
钻进松软、非固结，通常是浅地层时，通过仅仅依靠液力冲击载荷去冲蚀破碎钻头下的岩石。
2
The results of the research have the important reference and guidance effect to design the hydraulic structure of the PDC bit that using in drilling horizontal well.
该研究成果对水平井PDC钻头的水力结构设计有着重要的借鉴和指导意义。
3
According to the analysis, it is showed that drill bit design should be combined with hydraulic character of the flow field.