四川盆地超深层钻完井技术进展及其对万米特深井的启示

Progress in ultra-deep drilling and completion technology in the Sichuan Basin and its implications for extra-deep wells of more than ten thousand meters in depth

四川盆地超深层海相碳酸盐岩油气资源丰富,是寻找特大型油气田、开拓油气增储上产新领域的重要方向,但超深层钻完井面临地层条件更加复杂、井筒环境更加极端等工程技术挑战。为进一步指导万米特深井的安全高效钻探,通过梳理超深层钻完井技术难点,系统总结了四川盆地超深层钻完井关键技术,并提出了下步钻完井技术的发展建议。研究结果表明:①形成的超深复杂地层三压力预测监测技术精确预测了复杂地层压力系统及地应力场分布,准确刻画断层、裂缝、溶洞等展布规律,结合非常用井身结构拓展技术,提高了井身结构设计应对复杂地层钻探的能力;②形成的钻—测—固—完全过程精细控压技术,解决了超深井、特殊复杂井钻井液安全密度窗口窄导致“溢漏共存”、固井质量低等难题;③研发的高效钻头与大扭矩螺杆、扭力冲击器等抗高温提速工具,解决了深部难钻地层钻井钻头易磨损、破岩效率低的工程难题;④研发的抗高温钻井液体系提升应对高温深井的钻井液技术保障能力,升级第二代韧性水泥,解决了工作液抗高温能力不足等难题,保障超深井建井质量。结论认为,超深层钻完井技术的发展与进步,使得深井钻深能力突破9000 m已经成为现实,形成的关键技术有力地支撑了四川盆地超深层油气资源的高效勘探开发,对于万米特深层科学钻探和油气增储上产新领域拓展具有重要技术支撑作用。

The ultra-deep marine carbonate rocks in the Sichuan Basin are rich in oil and gas resources,which is an important direction for searching for super large oil and gas fields and exploring new fields for oil and gas reserves and production increase.However,drilling and completion of ultra-deep wells face engineering and technical challenges such as more complex stratigraphic conditions and more extreme wellbore environments.In order to provide a guidance for the safe and efficient drilling of extra-deep wells of ten thousand meters deep,this paper sorts out the technical difficulties in ultra-deep drilling and completion,systematically summarizes the key technologies in the ultra-deep drilling and completion in the Sichuan Basin,and proposes the development of drilling and completion technologies in the next step.And the following research results are obtained.First,the three-pressure prediction and monitoring technology for ultra-deep complex strata can accurately predict the distribution of pressure system and in-situ stress field in complex strata,and accurately describe the distribution laws of faults,fractures and vugs.And combined with the unconventional well structure prolongation technology,it can improve its ability of casing program design to deal with the drilling in complex strata.Second,the fine pressure control technology for the whole process of drilling,logging and cementing can solve"overflow and leakage coexistence",poor cementing quality and other problems caused by narrow safety density window of drilling fluid in ultra-deep wells and special complex wells.Third,the high-temperature ROP improvement tools such as efficient bit,large-torque screw and torsional impactor can address the engineering difficulties in drilling deep hard-to-drill strata,e.g.bit wear and low rock breaking efficiency.Fourth,the high-temperature drilling fluid system can enhance the ability to guarantee drilling fluid technologies in high-temperature deep wells.The upgraded second generation of tenacious cement improve the high temperature resistance of working fluid,ensuring the construction quality of ultra-deep wells.In conclusion,the development and advancement of ultra-deep drilling and completion technology has made the drilling depth of over 9000 m come true.Those key technologies provide a powerful support for the efficient exploration and development of ultra-deep oil and gas resources in the Sichuan Basin and play an important role in supporting the scientific drilling in extra-deep strata of ten thousand meters in depth and the discovery of new fields for oil and gas reserves and production increase.