Simulation Modeling for Optimized LWD Fluid Sampling Under Different Invasion Profiles

Abstract

Understanding the properties of formation fluid is a critical step in reservoir characterization. The use of Logging While Drilling (LWD) based fluid sampling becomes increasingly important in high risk scenarios. The LWD environment is significantly different from that of Wireline (WL) for sampling operations as the dynamic filtrate invasion is still in effect. LWD sampling is a relatively new technology and its sampling efficiency compared to WL sampling is not well known. This study aims to understand the effects of dynamic invasion processes on LWD fluid sampling and compare its performance with WL based fluid sampling. The results of the simulation study performed revealed that when the wait time after the drilling is optimized, LWD can provide cleaner samples in shorter cleanup time than WL sampling. It also revealed that the reservoir fluid breakthrough time would be shorter in LWD sampling compared to that of WL. This study indicates that with proper modeling, an optimized sampling program can be executed to meet the objectives of the LWD sampling operations in the most economic manner.