Coal Body Structure Detection Based on Logging and Seismic Data and Its Impacts on Coalbed Methane Development: A Case Study in the Dahebian Block, Western Guizhou, Southern China
Tóm tắt
Coal mining and coalbed methane (CBM) development in Western Guizhou are hampered by the tectonically deformed coal (TDC). In this article, the support vector machine algorithm was used to train and establish coal body structure detection models based on logging and seismic data, and the coal body structure distribution in the Dahebian block was predicted. The fivefold cross-validation prediction accuracy for identifying coal body structure using logging data is 96.46%. The coefficient of determination of fivefold cross-validation for predicting coal body structure thickness using seismic data is generally greater than 0.99. The coal body structure distributions in the No.1, 4, and 7 coal seams are similar, containing about 2–3 layers, and are dominated by cataclastic coal. The primary undeformed coal is usually found in the inter-fault area, whereas the cataclastic and granulated coals are mostly developed along the fault. The No.11 coal seam generally has more than 5 layers of coal body structures, mainly granulated coal. The primary undeformed coal is primarily distributed along the fault, and the granulated coal is widespread and not restricted to the fault area. The No.11 coal seam contains the most CBM resources, with more than half stored in TDC. The CBM resources in the No.1, 4, and 7 coal seams are mostly stored in cataclastic and granulated coal. The cumulative gas production is adversely associated with the proportion of TDC, and the increase in the gas production rate of wells with a high proportion of TDC is relatively slow. When releasing stress through protective layer mining, the No.11 coal seam is suitable as the protected layer. The utilization of horizontal well cavity completion for stress relief is an appropriate approach for CBM development in the No.11 coal seam dominated by thick granulated coal. This study has significant theoretical guidance and engineering reference significance for coal mining and CBM development in the study area and areas with similar demands.