Target-entering control technology for SAGD parallel horizontal well drilling

Horizontality of horizontal sections and parallelism between horizontal sections of two horizontal wells are two key indexes in SAGD parallel horizontal well drilling. In order to ensure the high quality of these indexes, the deviation angle at the target entry point and the borehole direction have to be effectively controlled. Otherwise, the trajectory control of horizontal section would become more difficult and the workload would be increased, which has negative influence upon operation and recovery of crude oil. Based on deriving the range of average build-up rate in target-entering control, the influence factors were analyzed, including build-up rate control, azimuth control and magnetic disturbance. Principle for deciding target-entering deviation angle in SAGD parallel horizontal well drilling and approaches of trajectory control for different conditions were proposed. Theory and practices have proved that it is better for the landing of horizontal well when making the deviation angle in advance appropriately and the position of actual track points are near or a little bit behind that of designed trajectory. The research results have directive significance for target-entering controlling technology in parallel horizontal well drilling and large-scale development of heavy oil reservoir with SAGD.