Comparison of Burial Diagenesis in some Deltaic to Shallow Marine Reservoir Sandstones from Different Basins

Strikingly similar diagenetic histories of the deltaic to shallow-marine sandstones from the Bengal basin, the Gulf Coast basin, the Denver basin and the North Central Texas, have been noted. The diagenetic events include an initial phase of compaction and cementation with sequentially developed authigenic clay rims, quartz overgrowth and calcite cements, a secoud phase of secondary porosity development by rock component dissolution and a final less important phase of recementation with kaolinite and 'other cements. All the sandstones have comparable detrital composition and textural properties. Similarities. in depositional environments have contributed to establish similar set of facies relationships among sandstones and shales in terms of sand body geometry. sand-shale ratio, sedimentary texture etc. in these sequences. Inorganic and organic diagenetic reactions in shales have influenced the composition of their contained water that migrated during compaction into the adjacent sandstone into which mass transfer from shales is supposed to have taken place. The above factors presumably . lead to similar sort of fluid flux and fluid composition in the sandstones, meaning that the pore fluid evolution in the above sandstones have common links. It is envisaged that these common links are perhaps responsible for the similarities in the diagenetic events in all these sandstones.