Permian mixed carbonate–siliciclastic lagoon coastal system in West-Central Gondwana

Self-Sourced Unconventional Tight Marlstone Reservoir Potential from Evaporative Lagoon of Triassic Leikoupo Formation in the Central Sichuan Basin

“…Carbonate reservoirs generally include dolomite and limestone reservoirs, and dolomites generally have high porosity and permeability and can be served as high-quality reservoirs in petroliferous basins globally [16][17][18][19][20]. However, the reservoir potentials of limestone and marlstone often get overlooked due to their small pore sizes [21][22][23]. In some basins, marlstone has a high abundance of organic matter and acts as the source rock [24][25][26][27].…”

Mineralogy and Pore Structure of Marine–Continental Transitional Shale: A Case Study of the Upper Carboniferous Keluke Formation in the Eastern Qaidam Basin, China

“…Organic-rich shales and associated fine-grained transitional deposits in the Upper Carboniferous Keluke Formation in the Eastern Qaidam Basin were primarily developed in the tidal flat and lagoon facies (Zhang et al, 2016), forming frequently mixed carbonatesiliciclastic sequences (Wei et al, 2018). Currently, mixed carbonate-siliciclastic fine-grained rocks in continental and marine facies and their roles in petroleum accumulation have been widely investigated (Zecchin and Catuneanu, 2017;Abdel-Fattah et al, 2018;Zhang et al, 2018), whereas forming mechanism of high-quality reservoirs in transitional finegrained rocks is poorly understood (Ng et al, 2019;Silva et al, 2021). Previous researchers have evaluated shale gas prospects of the Carboniferous sequences in the Eastern Qaidam Basin based on outcrops and shallow well data, which reported that the Keluke Formation had good shale gas enrichment conditions (Yang et al, 2014;Liu et al, 2016).…”