削减PDC钻头泥包提高机械钻速的技术途径

采用PDC钻头与水基钻井液配合方式钻进泥页岩地层时，如何防止钻头泥包成为提高钻速的一大技术难点。为此，首先介绍了国外水基钻井液和水基钻井液添加ROP增速剂的钻头提速室内模拟实验取得的成果；然后用典型实例分别评述了PDC钻头优化（结构、氮化处理）以及在泥岩段地层中应用水基钻井液添加ROP增速剂的提速效果。考虑到钻井液的费用和环保问题，认为加入ROP增速剂的水基钻井液配合抛光PDC钻头将是软泥岩地层提速的有效技术途径，其应用一定会有更广阔的前景。

Technical methods for mitigating PDC bit bailing and improving the rate of penetration(ROP)

The prevention of bit bailing has become a bottlenecking problem in the improvement of rate of penetration(ROP) when a PDC bit is used for drilling in shale formation together with water-based drilling fluids.This paper first introduced foreign water-based drilling fluids and the achievements in indoor simulating experiments on the ROP enhancement by adding accelerating agents into the water-based drilling fluid.Then some typical case histories were used to make comments on the PDC bit optimization(structure and nitrogen treatment) and the acceleration effect of drilling in shale formations by use of the water-based drilling fluid with ROP accelerating agents added.Moreover,concerning the drilling fluid cost and environmental protection,it is regarded as an effective technical method to improve the ROP when drilling in soft mudstone formations using the polished PDC bit along with the water-based drilling fluid with ROP accelerating agents added.