Organic petrology and coalbed gas content, Wilcox Group (Paleocene–Eocene), northern Louisiana

Fate of injected CO 2 in the Wilcox Group, Louisiana, Gulf Coast Basin: Chemical and isotopic tracers of microbial–brine–rock–CO 2 interactions

“…Well-logs show that there are continuous and discontinuous coal beds throughout the stratigraphic area that was sampled for this study (SONRIS, http://sonris.com/dataaccess.asp). The gas content of Louisiana Wilcox Group coals (ranging from 0.37 to 7.3 cm 3 /g, as-analyzed) generally increases with depth, while moisture content (ranging from 13.0 to 36.2 wt%) decreases with depth Hackley et al, 2007). Adsorption isotherms from coal bed cores across Ouachita, Caldwell, and Winn Parishes of Louisiana indicate that the CH 4 saturation states varied tremendously (Hackley et al, 2007).…”

“…The gas content of Louisiana Wilcox Group coals (ranging from 0.37 to 7.3 cm 3 /g, as-analyzed) generally increases with depth, while moisture content (ranging from 13.0 to 36.2 wt%) decreases with depth Hackley et al, 2007). Adsorption isotherms from coal bed cores across Ouachita, Caldwell, and Winn Parishes of Louisiana indicate that the CH 4 saturation states varied tremendously (Hackley et al, 2007). Isotopic data collected from gases of both coal and sandstone reservoirs indicate that CH 4 produced from the Louisiana Wilcox Group coal-bearing interval is mostly microbial in origin, formed predominately by CO 2 reduction, from biodegradation of in-situ coals and/or oil with some mixing of migrated thermogenic gas (Warwick et al, , 2008McIntosh et al, 2010).…”

Petrographic Controls on Pore and Fissure Characteristics of Coals from the Southern Junggar Coalfield, Northwest China

“…The coal pores in coal facies (3) and (4) have mean multi-scale pores with medium IMS and EMW values (Figure 9c 1 ,d 1 ). The EMW of coal pores (72%) in facies (3) is higher compared to that (41.7%) in facies (4). This phenomenon results in the former NMR second peak entirely vanishing (Figure 9c 2 ), showing that pores and fissures are well-connected.…”

“…The small diminution in the first NMR peak shows that the micropores are partly interconnected (Figure 9a2 and c2). The residual amplitude after centrifuging implies pores and fissures are isolated (Figure 9d2), resulting in the comparatively low EMW values in coal facies (4). Further, Figure 10 presents microscopic features of pore and fissure of coal samples in four coal facies.…”

“…The productivity and recovery efficiency of methane in coal are primarily affected by physical properties of coal reservoirs [1,2], which in turn are controlled by the structural, physical, and chemical properties of maceral groups and coal ranks [3][4][5]. Variation in maceral groups depends on the depositional environment of the peat precursor and paleomire type [6], while coal rank is dependent upon the degree of coalification expressed by variation in fixed carbon and moisture [7].…”