Geological Modeling And Favorable Area Prediction Of No.15 Coal Reservoir In Anze Block Of Qinshui Basin

Anze block,located in the south of Qinshui Basin,is a new developing area for coalbed methane(CBM)resources.Previous studies mainly focus on No.3 coal seam in this area,but less relating to the research of the No.15 coal seam.This thesis carried out the investigation of the No.15 coal seam,in which seismic data and logging data are used to interpret geological structure,to identify coal structure,and to found the geological model of coalbed methane reservoir.As a result,the most favorable area for CBM development was predicated.This study provides theoretical and practical significance for guiding the development of No.15 coal reservoir.The fine horizon tracking was achieved by using synthetic seismogram and horizon calibration.Based on 3D seismic fine structure interpretation,the small-scale fracture and collapse column of No.15 coal seam were effectively recognized.The results show that the structure in the study area is relatively simple,and it becomes gradually complicated from southwest to northeast.A Support Vector Machine(SVM)evaluation model was established.Results show a correct rate of 85% based on the actual data of the coal structure properties,indicating that the SVM method successfully standardized the evaluation of coal structure.In the Anze block,the distribution of primary coal is limited in the middle and scattered in the northern part;the cataclysmic-structure coal is the most widely distributed,mainly in the south of the area;and the granular-structure coal is mainly concentrated in the west and east of the area.Based on the advanced seismic and logging interpretation data,the structure model of the top of the No.15 coal seam was established.The thickness of coal seam No.15 showing the trend of deep in north and east,but shallow in south and west.Lithofacies modeling of No.15 was made by using stochastic modeling method.The reservoir properties including gas content,porosity,permeability,thicknesses of coal seam and its interlayers were evaluated and discussed for their geological controls.Based on the Grey Relational Analysis,seven factors including gas content,porosity,permeability,coal seam depth and coal seam thickness were comprehensively analyzed,and the favorable areas for CBM development were predicted.It is found that the favorable areas are near A17 and A22 in the southeastern,the sub-favorable areas are mainly distributed in the marginal area and northeast of favorable areas.