超深井新港1井钻井技术实践与认识

摘要

Well Xin' gang 1 is the deepest ultra deep exploration well of Dagang oilfield with designed depth of 6 700 m. Because of ultra deep depth and several pressure systems existing, the difficulty of well structure design is extremely large. The Well Xin’ gang 1 is characterized by deep buried targets formation, super hard lithology, low ROP, and large sets of basalt in Dongying and Shahejie formation could easily lead to well collapse and leak. The cementing quality is difficult to be ensured because the long open hole interval of 2 380 m in the third spudding and large temperature difference between upper and lower hole. Besides, the high downhole temperature challenges to the performances of drilling fluid, and complicated geological lithology of build-up and hold interval requires a tough task of well trajectory control. Aiming to these difficulties, Mountains of work has been done from the aspects of well structure program optimal design, anti-high temperature drilling system selection, ultra-deep well trajectory control, ultra deep well cementing, ROP improving and safety operation. Based on these efforts the well finally was completed successfully, which accumulated a wealth of experience about ultra deep well drilling technology in Dagang oilfield.%　　新港1井是一口定向超深探井,设计井深6700 m,由于井深且存在多套压力系统,井身结构设计难度大；该井主要目的层埋藏深、地层岩性坚硬,机械钻速低；东营组、沙河街组存在大套玄武岩,易垮易漏；三开裸眼段长达2380 m,上下温差大,固井质量难以保障；井底温度高,对钻井液性能要求高；造斜、稳斜段岩性复杂,井眼轨迹控制难度大。针对这些钻井难点,从井身结构优化设计、抗高温钻井液体系优选、超深井井眼轨迹控制、超深井固井、提高钻井速度、安全优质施工等方面做了大量工作,高质量完成了钻探任务,为大港油田超深井钻探技术积累了成功经验。