Research on coal seam cutting response characteristics and logging evaluation method

Wang Wenwen; Liang Yunan; Wang Zhenguo

doi:10.19896/j.cnki.mtkj.2025.01.002

Abstract：There are significant differences between coal reservoirs and conventional reservoirs in terms of properties,components,and gas occurrence.At the same time,the coal seams have a complex cleat system.The degree of cutting development is closely related to changes in permeability,therefore,effectively evaluating the cleat development of coal seams is of great significance for the efficient de-velopment of coalbed methane.Experimental analysis found that changes in the development of coal seam cleats will cause significant changes in longitudinal and transverse wave velocities,that is,the velocities of longitudinal and transverse waves are sensitive to cleat density,so the cleat development status of the formation can be obtained from the log longitudinal and transverse wave velocities.Based on the Biot porous media theory,the impact of cleats on the elastic properties of the media and the local flow effect between pores and cleats are introduced into the original equation,thereby increasing the cleat density and the cleat aspect ratio,which are the key to de-scribe the cleat parameter.Combined with coal and rock CT analysis data,the development degree of single well cleat in a certain block in the southern Qinshui Basin was processed,the cleat density and cleat aspect ratio distribution characteristics of the block coal seam was obtained,and the effect of cleat characteristic parameters on the coal seam was analyzed.