Geochemical characteristics of shale gas formation and the potential for carbon storage in Thailand: An example from the Triassic Huai Hin Lat Formation

An evaluation of the potential shale gas play and geological carbon dioxide (CO2) storage from the Triassic Huai Hin Lat Formation in Thailand was performed based on field observations and mineralogical and geochemical data. This study was mainly focused on mudstone samples in some parts of the Huai Hin Lat Formation. The samples can be divided into three groups based on their mineral compositions as follows: coaly mudstone, carbonate-siliceous mudstone, and carbonate mudstone. The brittleness index based on their mineral compositions indicates that the samples show ultra-high carbonate and quartz contents, which suggests a good hydraulic fracture candidate. Total organic carbon and extractable organic matter of the samples represents poor to excellent generation potential for hydrocarbon source rock with type III kerogen. The depositional environment shows that the Huai Hin Lat Formation occurs in anoxic to suboxic conditions in an aquatic depositional environment. The formation is suitable for geological CO2 storage, which may reduce CO2 during petroleum production and increase the production rate. Consequently, results from this study are useful for unconventional shale reservoir exploration and carbon storage technology in Thailand and adjacent countries.