Transforming Gas While Drilling Analysis Workflow for Addressing Missed Opportunities in Exploration

Gas while drilling (GWD) data serves as a critical dataset for early detection of hydrocarbon presence in reservoirs. This is achieved through the analysis of total gas measurement and the examination of gas composition, spanning from C1 to C5, to offer an early indication of the formation fluid present, including gas, condensate, and oil. Integration of total gas data, gas composition, cutting observations, and log responses becomes imperative, particularly in wells with complex lithology and within unexpected hydrocarbon-bearing sections. Although the standard practice involves calibrating GWD data against laboratory fluid analysis from downhole fluids to enhance interpretation, the effectiveness of such calibration methods may be compromised due to the distinct acquisition nature of GWD and downhole fluid data. GWD on the other hand is exposed to various uncontrolled environmental and operational conditions, such as flow rate, rate of penetration, changes in mud properties, and extraction efficiency. These factors can to some extent influence the quality of the analyzed gas in the mud logging unit. In this study, we propose an robust gas analysis workflow aimed at refining the interpretation of GWD data, ultimately addressing missed opportunities in identifying hydrocarbon-containing reservoirs.