Prediction of coal seam details and mining safety using multicomponent seismic data: A case history from China

Abstract

With the increasing mining depth of coal mines, geologic hazards have become the main source of accidents. For this reason, coal seam prediction requires more assessment parameters, such as the degree of anisotropy, [Formula: see text] value, and elastic modulus. These parameters are difficult to determine using only the PP-wave. We have inverted and interpreted multicomponent seismic data acquired from a [Formula: see text] area in the Guqiao mine located on the southern margin of the North China plate, under the constraints of drill, log, and rock-physics test data. The production coal seam 11-2 of the mine, located in the Permian Formation, was our focus of this study, and our objective was to determine the structure, fracture development, thickness, surrounding rock lithology, roof stability, and mining safety of the seam. To achieve this, we first performed an analysis of S-wave splitting and joint PP- and PS-wave inversions. The inversion results were then combined to derive additional parameters, such as the [Formula: see text] value and dynamic Young’s modulus. Finally, we established a safety coefficient for assessing the safety of coal mining. The coefficient was based on the degree of anisotropy, coal bed thickness, Young’s modulus, and [Formula: see text] value of the coal-bearing strata. The geologic data for two mining tunnels in the 11-2 coal bed, provided by Huainan Coal Mining Group, were used to verify the known structure and lithology predictions. In addition, the known structural interpretations based on the PP- and PS-wave sections were obviously superior to the results of a previous survey based on the PP-wave only. The predicted thickness of coal seam 11-2 was accurate, as confirmed by comparison with that determined from drill data. Our joint PP- and PS-wave inversion and interpretation provides more information for coal seam prediction, creating a new application for coal seismic survey.