Log interpretation for coal petrologic parameters: A case study of Hancheng mining area, Central China

Aiming at a serious obstacle for building a log interpretation model to accurately interpret density and sonic speed value of each coal component which cannot be measured directly in lab scale, a log interpretation method of coal reservoir parameters was studied using the Hancheng mining area as an example. The enumeration method was used to calculate density and sonic speed value of fixed carbon, ash, and volatile according to experimental determination of industrial components, pore, gas content, density and sonic speed value of many coal samples in the Hancheng mining area. On the basis of the relationships of each coal component and its density and sonic speed value, logging response relationships between each component and its compensated density and acoustic travel-time differences were studied using numerical fitting. As fitted carbon content increases and ash content decreases, density decrease and sonic speed difference increase. By combining statistical analysis method and theory model calculation method, interpretation models of industrial components, gas content and pore for coal reservoirs were built and a logging integrated interpretation software was programmed, which have got good effect in actual application.