昌吉油田致密油长位移丛式水平井钻井技术

Drilling Technology of Large Displaced Cluster Horizontal Well for Tight Oil in Changji Oilfield, Junggar Basin

美国致密油成功开发的经验表明,适宜的工程技术与“工厂化”运行模式的有机结合是降低开发成本的有效手段.为了进一步降低开发成本,昌吉油田致密油有效开发试验区采用了大井丛平台水平井开发方式,以满足“工厂化”作业模式需要.针对昌吉油田二叠系芦草沟组致密油钻井地质特点,阐述了井身结构优化设计、钻头优选、水平井眼方位选择、三维井眼轨迹优化设计与精细控制、丛式井防碰以及钻井液体系优选等关键技术,通过现场试验,井身结构实现了由四开变三开,机械钻速较前期探井提高了2.46倍,钻井工期缩短了82.75 d,采用常规定向工具满足了1 300～1 800m水平段三维井眼轨迹控制要求,钻井成本大幅度降低,为该区致密油有效开发创造了有利条件.

The low-eost strategy is the core of development of tight oil. The experience from successfully developing tight oil in USA shows that the combination of suitable engineering technique and factory operation mode is the effective ways to reduce the cost. In order to further reduce the development cost, Changji oilfield tight oil test area in Xinjiang has employed the large cluster platform horizontal wells to meet the need of the factory operation mode. According to the geologic characteristics of tight oil of Permian in Changji oilfield, this paper introduces the key technologies such as optimizing the structure of the hole, PDC bit type selection, selection of horizontal well azimuth, optimal design and fine control of 3D trajectory, anti-collision of cluster horizontal wells and optimization of drilling fluid systems. The well structures turn four into three by field experiment. Compared with the previous, the average rate of penetration is increased by 2.43 times, drilling duration is reduced by 82.75 d. The conventional deflecting tools meet the demands of well trajectory control of 1 300- 1 800 m horizontal section, and the drilling costs are greatly cut. All of these create favorable conditions for effective development of Changji oilfield tight oil.