延川南区块煤层气低成本钻井工艺技术探讨

Discussion on the lowcost drilling technology in South Yanchuan CBM block

延川南煤层气区块位于鄂尔多斯盆地东缘南部,目前已进入开发阶段。相对于常规油气井,煤层气井单井产量较低,开发过程中只有实施低成本战略才能取得较好的经济效益。针对地层特点,对钻井井型、井身结构、钻井工艺、钻井液体系、装备配套等工艺技术进行了探讨,提出了在开展井身结构优化、普通钻机配套空气潜孔锤钻井先导试验的基础上,钻井井型方面以丛式井为主、钻井工艺方面以空气旋冲钻井工艺技术为主、钻井液体系方面以低成本水基钻井液为主、钻机选型方面以采用车载全液压钻机和2 000 m钻机为主等低成本钻井方案。

South Yanchuan CBM block lies in the eastern fringe of Ordos basin and is in the development phase at present. Rela- tive to the conventional oil gas well, the product of CBM single well is low. Only by putting a lowcost strategy into practice can eco- nomic benefit be better achieved in the development process. In view of the formation characteristics, this paper carries out a dis- cussion on the well type, well structure, drilling technology, drilling fluid systems and matching equipment. Based on the well struc- ture optimization and the pilot program of ordinary drilling rig with DTH hammer, this paper also brings forward a low cost drilling proposal which advices us to mainly adopt the cluster well, mainly use the lowcost water-based drilling fluid, and mainly choose the vehicle mounted full hydraulic drilling rig and 2 000 m rig.