渤海中深层天然气田钻完井关键技术现状及展望

渤中凹陷西南环带深层含油气构造是渤海湾乃至我国东部迄今发现最大的中深层天然气田，针对该区域地质条件复杂、储层埋藏深、地层压力异常、可钻性差等特性，分析了开发过程中在异常压力预测、钻井效率、储层保护、钻井综合提速、井壁稳定、井筒安全及井控风险方面面临的技术难点，系统总结了近十余年现场实践形成的渤海中深层天然气安全环保高效勘探开发的钻完井关键技术体系，包括地质工程一体化快速评价、井身结构优化及安全控制、中深层钻井提速、抗高温低密度钻井液及储层保护、深层潜山中途裸眼测试等关键技术。随着渤海中深层天然气勘探领域的进一步拓展，会面临更为复杂的地质特征，面临越来越大的技术挑战，提出了未来渤海中深层天然气开发的钻完井技术应加强能适应更复杂地质工况的设备、工具、材料、新工艺技术的研发以及完善海上应急救援体系，保障渤海中深层天然气钻井的安全、环保和高效。

Status and prospect of key drilling and completion technologies used in middle-deep natural gas fields of the Bohai Sea

The deep-seated oil and gas bearing structure in the southwest zone of Bozhong sag is the largest middle-deep natural gas field in the Bohai Bay and even in eastern China. To deal with the complex geological conditions, great reservoir depth, abnormal formation pressure and poor drillability in this area, the technical difficulties in the process of gas field development were analyzed from the aspects of abnormal pressure prediction, drilling efficiency, reservoir protection, comprehensive ROP (rate of penetration) improvement, borehole stability, wellbore safety and well control risk. Then, the key drilling and completion technologies that have been developed for the safe, environmental and efficient exploration and development of middle-deep natural gas in the Bohai Sea based on field practice in recent ten years were summarized systematically, including geology-engineering integrated fast evaluation, casing program optimization and safety control, middle-deep ROP improvement, high-temperature low-density drilling fluid and reservoir protection, and open hole DST in deep buried hill. With the further expansion of exploration field of middle-deep natural gas in the Bohai Sea, the geological characteristics will be more complex and the technical challenges will be more difficult. Finally, therefore, it was proposed to strengthen the research and development of the drilling and completion equipments, tools, materials and technologies for the development of middle-deep natural gas reservoirs with more complex geological conditions in the Bohai Sea and complete the offshore emergency rescue system, so as to guarantee the safety, environmental protection and efficiency of middle-deep gas well drilling in the Bohai Sea.