A mathematical method to identify and forecast coal texture of multiple and thin coal seams by using logging data in the Panguan syncline, western Guizhou, China

Abstract

There are abundant coalbed methane (CBM) resources in the western Guizhou Province, China. The high efficiency development of CBM in western Guizhou is restricted to a great extent by multiple and thin coal seams, the high in-situ stress and the complex coal texture. By using the mathematical principle of Linear Discriminant Analysis (LDA) method, 1508 logging data obtained from three CBM wells are related to their geophysical logging responses. Four types of well-logging curves of the natural gamma ray (GR), densities (DEN), acoustic logging (AC) and deep lateral resistivity (LLD) were chosen to analyze coal texture. The mathematical method reflecting the relationship between typical logging data and coal texture was established, which has a high accuracy for identifying the coal texture of medium-thin coal seams. The results show that tectonic coal in western Guizhou is developed and complicated. The coal texture predicted by the established method is in good agreement with that of actual coal core, which plays an important role in the joint and efficient development of CBM in the multiple and thin coal seams in western Guizhou.