CHARACTERIZATION OF COAL-BEARING FORMATION FOR UNDERGROUND COAL GASIFICATION IN NORTH DAKOTA

Successful underground coal gasification (UCG) projects require good understanding of the natural properties and in situ geological/hydrogeological condition of the coal-bearing formation. Characterization of the coal-bearing formation is an important procedure in UCG site selection, and provides essential information for the gasification process design. A potential UCG site in the Fort Union Formation, western North Dakota is screened out, and related characterization works of the selected site are conducted. A facies model of the coal seam and its adjacent rocks is established to visualize the lithological contents, and recognize aquifers close to the coal seam. Rock samples of sandstone, mudstone and claystone are collected, and geomechanical tests are conducted to measure their properties, including porosity, permeability, strength, Young’s modulus, Poison’s ratio etc. Results of this work provide detailed knowledge about the target UCG site, and will support dynamical modeling of the gasification process. These parameters will also be used to predict geomechanical and hydrogeological responses during and after gasification, as well as to assess environmental issues associated with the UCG project.