PDC钻头钻井提速关键影响因素研究

Study on Key Factors Influencing the ROP Improvement of PDC Bits

高德利 刘维 万绪新 郭勇

GAO Deli LIU Wei WAN Xuxin GUO Yong

石油工程教育部重点实验室（中国石油大学（北京）），北京 102249 中石化胜利石油工程有限公司，山东东营 257000 中国石油新疆油田分公司工程技术研究院，新疆克拉玛依 834000

MOE Key Laboratory of Petroleum Engineering, China University of Petroleum (Beijing), Beijing, 102249, China Sinopec Shengli Oilfield Service Corporation, Dongying, Shandong, 257000, China Engineering Technology Research Institute, PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang, 834000, China

为了在钻井工程中发挥出PDC钻头的最大功效，通过理论分析、室内试验、案例分析、现场试验等，探讨了高钻压、高转速等钻井参数强化对PDC钻头钻速和磨损的影响规律，同时分析了PDC钻头的磨损机理与过早失效主因。研究结果表明：1）钻压是影响PDC钻头机械钻速的直接和首选因素，当钻头处于高效破岩状态时，无论钻遇一般地层还是硬岩地层，钻压与机械钻速均应呈线性关系；钻遇均质硬岩地层时，建议将200 kN以上高钻压纳入PDC钻头的常规应用参数；2）提高转速可实现钻井提速，虽然高转速会加剧PDC钻头的磨损，但目前切削齿的质量足以满足PDC钻头在高转速（400～500 r/min）下长时间钻进多数地层的需求；3）布齿密度对钻头机械钻速有影响，但并非直接因素，只要“吃得进去，切得下来，排得及时”三者建立动态平衡，即便是高布齿密度PDC钻头也可以实现优快钻进；4）PDC钻头破岩效率越高，钻头磨损会越小，如提高钻压，会增大切削齿吃入深度、减少钻头磨损；5）动态冲击和低效破岩是造成PDC切削齿和钻头过早失效的主因，实现PDC钻头高效钻进的核心是提高破岩效率与抑制钻头振动。该研究结果对PDC钻头合理使用与钻井提速技术创新具有参考意义。

For the maximization of the efficacy of the polycrystalline diamond compact (PDC) bits in drilling engineering, comprehensive research, including theoretical analysis, laboratory test, case study, and on-site trials, was conducted to investigate how a high weight-on-bit (WOB), a high rotary speed, and other optimized drilling parameters work on the rate of penetration (ROP) and the wear of a PDC bit. Furthermore, the wear mechanism of the PDC bit and the primary cause of the premature failure of the bit were analyzed. The results indicated that: 1) The ROP of the PDC bit was directly and primarily affected by the WOB. When the bit was in an efficient rock-breaking state, the WOB was invariably in a linear relationship with the ROP whether the formation encountered was a conventional one or a hard rock formation. Adding a high WOB over 200 kN into the normal pressurization range of the PDC bit was recommended if the formation encountered was a homogeneous hard rock formation. 2) ROP improvement could be achieved by enhancing the rotary speed. Although the wear of the PDC bit could be aggravated by a high rotary speed, the requirement on a PDC bit to penetrate most formations for a long time at a high rotary speed (400–500 r/min) could be readily met by the quality of the currently available PDC cutter. 3) The ROP of the bit was also affected by cutter density, but not in a direct manner. As long as a dynamic balance among “capabilities to bite into the formation, cut the rock, and evacuate the cuttings in time” was reached, the optimized fast drilling could be achieved even by a PDC bit with a high cutter density. 4) The wear of the PDC bit was less severe under the higher rock-breaking efficiency of the bit. The WOB could be enhanced to improve the ROP and reduce bit wear. 5) Dynamic impact and inefficient rock-breaking were considered the primary causes of the premature failure of the PDC cutter and bit. The key for the PDC bit to achieve efficient penetration was improving rock-breaking efficiency and restraining bit vibration. The above results could be used as a reference for the proper utilization of PDC bits and the innovation of ROP improvement technologies.

国家自然科学基金重点项目“复杂结构‘井工厂’立体设计建设基础研究”（编号：52234002）、国家自然科学基金创新研究群体项目“复杂油气井钻井与完井基础研究”（编号：51821092）、中国石油大学（北京）科研启动基金项目“高效钻头的研究”（编号：ZX20190065）联合资助

https://doi.org/10.11911/syztjs.2023022