Seismic guided drilling technique based on seismic while drilling (SWD): A case study of fracture-cave reservoirs of Halahatang block, Tarim Oilfield, NW China

To deal with the inaccurate three-dimensional positioning of caves in the ultra-deep and high temperature Ordovician carbonate fracture-cave reservoirs in the Halahatang block, this article proposes a new integrated solution which combines seismic guided drilling (SGD) with onshore seismic while drilling (SVWD). SGD technique uses the newly acquired velocity by SVWD to update velocity model and re-place the target position in three-dimensional space to decrease the uncertainty of the target. The primary drilling targets of two wells in the Halahatang block have been selected to verify this solution. It's the first time to collect onshore SVWD date domestically. The two wells landed in the target successfully by guiding and adjusting wellbore trajectory according to near real-time prediction results obtained from SVWD data. The success of these two wells shows the solution combining SVWD with SGD is practicable in solving the misplacing of target reservoirs caused by velocity and geological model uncertainty.