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

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.