Characteristics of coal structure and construction of well logging model in Baoan block of Xinjing Mine

Coal structure is an important geological constraint for the exploration and development of coalbed methane in tectonic coal development area. Accurate identification of coal structure is the basis for optimizing the development plan of coalbed methane. In order to clarify the development rule of coal structure in the Baoan block of Xinjing Coal Mine, the logging curves were sorted out and analyzed by combining qualitative and quantitative methods. The results show that in the qualitative analysis stage, natural gamma ray, density, borehole diameter 2, deep investigate double lateral resistivity log and acoustic time difference have strong response to the change of coal structure, which basically reflects the change law of coal structure; in the quantitative analysis stage, through GSI assignment, single factor and multi-factor linear regression analysis and relative error analysis verification of the coal samples taken from drilling, a set of coal structure logging model suitable for the Baoan block of Xinjing Coal Mine is constructed. Based on the study, the development law of coal structure in the Baoan block of Xinjing Coal Mine has been defined. It is considered that the coal structure of Class Ⅰ, Class Ⅱ and Class Ⅲ in No.8 coal seam accounts for 36.16%, 30.51% and 33.33% of the total thickness of net coal respectively, the coal structure of Class Ⅰ, Class Ⅱ and Class Ⅲ in No.15 coal seam accounts for 28.43%, 50.73% and 20.84% respectively. In terms of property of Class Ⅲ coal, the coal structure of No.15 coal seam is slightly better than that of No.8 coal seam.