Coalbed Methane Reservoir Characterization and Geological Modeling: A Case Study of Block A in the Shenfu Gas Field, Eastern Margin of the Ordos Basin.

In recent years, with the growth of global demand for oil and gas, coalbed methane, as an important unconventional resource, has become a research hotspot in the field of exploration and development. However, coal reservoirs typically exhibit strong heterogeneity, with significant variations in microscopic components, pore characteristics, and coal body structures, making it challenging to identify the distribution of favorable reservoirs. To address this issue, this study proposes a novel approach to coal reservoir characterization and modeling based on coal macrolithotypes. The method uses core observation and experimental analysis to determine the geological characteristics of favorable macrolithotypes, thereby guiding the construction of the coal reservoir geological models. It not only delineates the spatial heterogeneity of coal reservoirs but also provides an effective framework for predicting favorable coal reservoirs. The method is successfully applied to block A of the Shenfu gas field, located on the eastern margin of the Ordos Basin. Results indicate that bright coal and semibright coal are favorable coal reservoirs in this area, characterized by superior gas generation and storage capacities. They are primarily distributed in the central part of the study area horizontally and concentrated in the upper middle part of the coal seam vertically, forming the key target interval for development. Finally, the reliability of the proposed approach is verified through comparison to production performance from actual wells. Therefore, this method provides a robust basis for predicting favorable coal reservoirs and offers a valuable guide for improving the coalbed methane development efficiency and achieving increased production.