长庆油田陇东地区页岩油大偏移距三维水平井钻井技术

Drilling Technology for Long-Offset 3D Horizontal Shale Oil Wells in the Longdong Area of the Changqing Oilfield

长庆油田陇东地区页岩油施工区域沟壑纵横,水资源、基本农田和森林资源保护区较多,采用水平井开发受地形地貌及资源保护区影响较大,三维水平井偏移距的大小直接影响水平井平台布井数量及大平台工厂化作业,影响地下资源的有效动用。为此,在分析大偏移距三维水平井特点及钻井难点的基础上,优化剖面设计,优选造斜点、消偏井斜角、方位角及消偏井段,完善井眼轨迹控制方式,在不使用旋转导向系统的情况下优化常规螺杆钻具和PDC钻头,并综合应用降摩减阻工具及适用于页岩油大偏移距钻井的水基CQSP-4钻井液体系等,形成了陇东页岩油大偏移距三维水平井钻井技术。陇东地区6口水平段长度900.00 m以上的大偏移距三维页岩油水平井应用了该技术,摩阻扭矩明显减小,钻进安全高效,取得了很好的现场应用效果。该技术的成功应用,支撑了陇东地区页岩油大平台多层系多钻机工厂化高效开发,也支撑了钻井钻机作业方式由单机单队向工厂化、集群化转型。

Ravines and gullies criss-cross the shale oil reservoirs of the Longdong Area in the Changqing Oilfield,where there are also numerous protected zones for water and forest resources,plus prime farmlands.The development of horizontal wells is greatly restrained by the topography and protection zones,and the offset of 3 D horizontal wells directly affects the number of horizontal well platforms and the factory-like operation of large platforms,and affects the effective utilization of subsurface resources.Based on the analysis of the characteristics and drilling difficulties of long-offset 3 D horizontal wells,the wellbore profile design was optimized,and kick-off points,azimuths,deviation angles,and well sections for eliminating offset were selected to improve the control mode of hole trajectories.In the absence of a rotary steering system,conventional positive displacement motors(PDM)and polycrystalline diamond compact(PDC)bits were upgraded.In addition,tools for reducing friction and a water-based CQSP-4 drilling fluid system suitable for long-offset horizontal shale oil wells were employed.Finally,the drilling technology for long-offset3 D horizontal shale oil wells in the Longdong Area was developed.This technology was applied to 63 D horizontal wells with offsets over 900 m in Longdong Area.Friction torque was reduced significantly and the drilling process was safe and efficient,with good field application effect achieved.The successful application of the technology can support factory-like efficient development of the large shale oil platforms in the Longdong Area,which have multilayered systems and multiple drilling rigs.Further,it can facilitate the transformation of the drilling operation mode from single-rig and single-team to industrialized and clustered production.