深部及复杂地层中PDC钻头综合改进方法

A comprehensive method to improve the performance of PDC bits in deep and complex formations

深部及复杂地层条件下岩石普遍具有硬度大、非均质强、可钻性差、研磨性高等特点,因此钻速慢、寿命短、成本高等问题一直是制约PDC钻头在上述地层中高效应用的主要技术瓶颈,开展PDC钻头改进方法研究十分必要。通过对国内外PDC钻头最新产品及相关技术进行研究,从提高破岩效率、延长使用寿命、增强稳定性、优化定向性4个方面系统地提出了深部及复杂地层条件下PDC钻头综合改进方法,进而应用该方法设计了6只PDC钻头用于华北、东北等油田的花岗岩、硬砂岩、砾岩等难钻地层,均取得了优于常规PDC钻头及牙轮钻头的破岩效率和使用寿命,说明该综合改进方法具有较好的适用性和使用价值。研究成果可对深部及复杂地层条件下PDC钻头个性优化设计提供指导。

The rocks in deep and complex formations are commonly characterized by high hardness,strong heterogeneity,poor drillability and high abrasiveness,so low rate of penetration(ROP),short service life and high cost have always been the main technical bottlenecks that restrict the efficient application of PDC bits in deep and complex formations.Obviously,it is of great practical significance to study further the methods to improve PDC bits.The latest PDC bits and the related technologies at home and abroad were investigated,and the comprehensive PDC bit improvement method for deep and complex formations was put forward from four aspects,i.e.,increasing ROP,prolonging service life,enhancing stability and optimizing steerability.Then,by virtue of this method,six PDC bits were designed to drill different types of hard formations(e.g.granite,competent sandstone and conglomerate)in Huabei and Northeast Oilfields.It is shown that these improved PDC bits are superior to conventional PDC bits and cone bits in terms of rock breaking efficiency and service life.It is indicated that this comprehensive improvement method has good applicability and use value.The research results provide the theoretical and practical guidance for the optimal design of PDC bits in deep and complicated formations.