Analysis of Spatial Differences in Permeability Based on Sedimentary and Structural Features of the Sandstone Aquifer Overlying Coal Seams in Western China

Abstract

A sandstone aquifer covers the primary mineable coal seam within the Jurassic Ningdong coal field in western China and threatens the safety of mining the shallow seam. Although geological boreholes were located in and surrounding the study area, no hydrogeological boreholes existed within it, so six factors (the ratio between the sandstone aquifer and entire strata thicknesses, sandstone thickness, grit thickness, number of sandstone layers, fault fractal dimension, and fold fractal dimension) were used as indicators of aquifer permeability. Using a pair-wise comparison approach, the influence weights of these six factors on the permeability coefficient were defined as 0.131, 0.243, 0.161, 0.106, 0.197, and 0.161, respectively. Integration of the area’s geological and hydrogeological conditions, and geological exploration, drilling, and three-dimensional seismic data resulted in partitioning of the permeability levels within the study area after fuzzy comprehensive evaluation. Comparing the results with actual conditions and the observed working panel water inflows verified that the proposed method for analysis of spatial differences can be used to guide future water prevention and control efforts.