涪陵页岩气田二期水平井钻井防碰绕障技术

Collision avoidance and obstacle bypass technology for horizontal wells in the second phase of Fuling shale gas field

涪陵页岩气田二期处于油藏边缘地带,地层倾角大、断层多。由于储层埋藏深,设计直井段长,防斜打直问题突出;为提高采收率并降低钻探成本,二期工程继续采用井工厂模式开发,但与一期相比,平台布井数量增加,井口距离小,防碰绕障难题亟待解决。以焦页81-1HF井为例,撰写了现场水平井防碰施工注意事项;结合同平台井组井史资料,优化设计了焦页81-1HF井身剖面;模拟邻井防碰数据,确定了防碰重点井位、井段,制定了防碰技术方案及定向施工措施,优选钻头、钻具组合,避免邻井防碰,降低作业风险。现场应用表明,同平台7口水平井防碰绕障成功,井眼轨迹光滑,准确中靶,为下套管及固井施工奠定了基础,为涪陵二期丛式水平井防碰绕障施工提供了借鉴。

Phase 2 site of Jiaoshiba shale gas project in Fuling is geographically located at the margin of oil reservoir with high stratigraphic dip and multiple faults. The reservoirs are buried deeply, so the vertical hole section shall be long. Therefore, inclination prevention is vital. To enhance recovery factor and decrease drilling cost, the phase 2 engineering is still developed in the mode of well factory. There are more wells in one pad and wellhead distance is shorter in phase 2 than in phase 1, so it is in urgent need to guarantee collision avoidance and obstacle bypass of horizontal wells. The seventh horizontal well（i.e., Well Jiaoye 81-1HF） on the Jiaoye 81 pad was taken as an example to investigate the collision avoidance which is the construction focus and difficulty in phase 2. The on-site considerations of horizontal well anti-collision were prepared. Well profile of Well Jiaoye 81-1HF was optimally designed based on the historical data of well group on the same pad. The key well locations and hole sections of collision avoidance were determined by simulating the anti-collision data of neighboring wells. Anti-collision technology program and directional construction measure were formulated. Bit and BHA were optimized. And thus, collision between one well and its neighboring well was avoided and the operation risk was reduced. It is indicated that collision avoidance and obstacle bypass are realized successfully at 7 horizontal wells on the same pad and their hole trajectories are smooth with accurate targeting. It provides the foundation for casing job and cementing. And it can be used as the reference for the collision avoidance and obstacle bypass of cluster horizontal wells in the second phase of Fuling shale gas project.