Seismic Attributes and Fault-Fold Systems: A Case Study of Quantitative Analysis of Coal Seams in the Southern Qinshui Basin, China

The formation of folds often leads to the emergence of subsidiary faults, thereby creating intricate fault-fold systems with fractures. While existing literature on fault-fold systems predominantly relies on field observations, there has been scant research focusing on their subsurface structures. Utilizing three-dimensional seismic data, this study endeavors to identify and quantify the principal fault-fold systems within the No. 3 coal seam of the Shanxi Formation and the No. 15 coal seam of the Taiyuan Formation, in the southern Qinshui Basin, China. The findings reveal: (1) The presence of five principal fault-fold systems, with four exhibiting a North-South orientation and one aligning East-West; (2) The establishment of an asymmetric model for the fault-fold system through a quantitative analysis of seismic attributes, particularly focusing on the high-angle normal faults along the folds' limbs; (3) The asymmetrical fault damage zone width (No. 3 fault-fold system) is quantitatively measured at approximately 200 meters on the west side, in contrast to the east side where widths range from 50 to 500 meters. These initial assessments show the great potential of an attribute-enhanced geological model, which may provide insights for analyses of the continuity of coal seams, the propagation of fractures, and the migration of gas within fractured reservoirs.#xD;