Real Time Advanced Mud Gas for Enhancing Geosteering Decisions

Summary Successful well delivery and optimal production highly depends on knowing the stratigraphic position in real- time of the bit, assuring always to be inside the target zone, driving the steering of the across long horizontal sections in hard abrasive formations with interlayering of siltstone and sandstone which could highly affect the quality of the reservoir. In this paper authors present a practical summary of mud gas log utilization in geosteering, and real-time decision making in development wells. The described methodology is particularly useful when drilling at lower rates of penetration (ROP), in highly abrasive formations and cases where logging while drilling (LWD) resistivity measurements are affected. Low contrast and low resistivity pay often make it challenging to use resistivity-based boundary mapping geosteering tools. Hydrocarbons encountered in such formations are difficult to quantify with Archie’s saturation models. To assist in overcoming such challenges, other data sources are necessary. Surface mud gas logging system enables near real-time decisions and integration with the downhole logging allows optimizing and reducing uncertainty of petrophysical evaluation. The practical new workflows approach of modern surface data logging systems to capitalize on the benefits for cost optimization and real-time decisions will be demonstrated.