Optimizing Horizontal Well Placement with Reservoir Characterized Modeling and Advanced Logging While Drilling Technologies

摘要

Successful placement of a horizontal well requires accurate landing of the well in the right position and keep the trajectory in good pay zone to maximize the reservoir exposure.Operators face operational and economic challenges in achieving accurate geosteering due to limited seismic resolution,measure depth error(reservoir depth that is more than 5000 meters),in addition to the uncertainty in reservoir depth from time to depth conversions,lateral reservoir variability further increase the challenges.Consequently,to optimize well planning and placement for optimized productivity,it is important to minimize uncertainties in the reservoir structure and delineate lateral distribution of the sand body. The paper provides a method used to optimize horizontal well positioning that uses three-dimensional (3D)geological model to reduce structural and lateral reservoir uncertainty based on reservoir charac- terization.These models are used as reference during proactive trajectory adjustments and model update when landing in alignment with advance distance-to-boundary well placement technique that utlilizes azimuthal deep directional electromagnetic logging-while-drilling(LWD)technology.To improve dril- ling efficiency while delivering smooth trajectory control,hybrid rotary steerable drilling system(RSS) with near bit Gamma ray measurement was engaged for this project. This paper also presents the results from field tests executed in Hadexun oilfield of Tarim basin of China that demonstrates the integration of technologies to spare pilot-holes,increase the drilling pene- tration rate while avoiding excessive adjustments to mitigate reservoir exits.The examples describe: 1.Accurately placed wells with significantly reduced probability of erroneous lateral placement along thin target layers 2.Avoiding water zone in a low resistivity pay reservoir. 3.Preventing sidetracks and deliver high Net to Gross(NTG). 4.An average production test of almost 50%incremental above the target projection 5.A 75%improvement to drilling efficiency from an average ROP in the 8?-in sections of 2.65 m/hr in previous wells to 4.65 m/hr. 6.Securing the economics to continue developing this deep oil bearing reservoir.