Assessment of the Shale Gas Resource Volumes in the Middle Portion of the Wulalike Formation, Western Ordos Basin

In recent years, several exploration wells targeting the middle portion of the Ordovician Wulalike Formation in the western Ordos Basin have successfully yielded industrial-scale gas flows, indicating substantial potential for future exploration. To evaluate the exploration and development potential, the total shale gas resources in the region have been estimated in this study. The methodology comprises the following steps: (1) evaluating the geological conditions for shale gas accumulation in the Wulalike Formation; (2) extracting key parameters (such as effective thickness, Langmuir pressure, and so on) from well logging, mud logging, and laboratory analysis data; (3) estimating the volumes of free and adsorbed natural gas resources; (4) constructing maps of resource abundance distribution patterns based on the calculation results. The results demonstrate that: (1) The Wulalike Formation constitutes a self-sourced reservoir system, where deep marine basin facies shale functions simultaneously as source rock, reservoir, and seal; (2) The favorable exploration area spans approximately 6,000 km2, with estimated shale gas resources of 0.6 × 1012 m3; (3) Resource enrichment is notably high in the central part of the study area, with resource abundance exceeding 2.0 × 108 m3/km2. This resource assessment of Wulalike Formation shale gas in the western Ordos Basin identifies optimized target areas for subsequent exploration and development activities.