Research on Seismic Identification Technology of Low-Order Faults in Coal-Measure Strata: A Case Study of H Well Area

Upon entering the development stage, small faults and microstructures within coal-measure strata assume utmost significance for the production of tight sandstone gas and coalbed methane, as well as for ensuring safe production. In the Daji Block, the coal-measure strata exhibit a relatively flat terrain overall, with a small formation dip angle and underdeveloped faults. However, there are still certain disparities among different well areas. The low - order structures in the H well area are comparatively complex. Against the backdrop of a west - dipping monocline structure, a series of small faults and small - scale folds have developed. The coalbed methane reservoirs in this area generally display a high water content, which may be directly correlated with the distribution of small faults and the development of fractures. This paper integrates a series of fracture identification techniques for coal-measure strata. In accordance with geological phenomena at different scales, technical means are optimally selected by category and hierarchy, and a fine - scale identification of low - order structures in coal-measure strata is carried out. Initially, the coherence attribute and quantitative maximum curvature identification techniques are employed to identify faults with a throw of approximately 10 m. Subsequently, the structural - oriented filtering + ant body tracing techniques are utilized to identify faults with a throw of around 5 m. Finally, the large - scale double curvature identification technique is applied to identify the distribution of folds. Through the above - mentioned identification of low - order structures, it provides a reference for the design of horizontal well trajectories and support for enhancing the production of horizontal wells.