Formation, preservation and damage mechanism of marine deep carbonate high quality reservoir rocks: Illustrated by Sinian system to Silurian in Sichuan Basin

Sinian system to Silurian (Lower group) carbonate rocks is generally buried deeper than 3500 m, which belonged to deep carbonate reservoir rocks. Broad tidal flat and shelf depositional environment determined the lower group carbonate rock reservoirs types which were grainstones, crystalline dolomite and fractured limestone. Multiple phases of tectonic movement led to the karst reservoir rocks development in lower group, Sinian, Cambrian and Ordovician paleokarst zone had occurred by the west to east caused by Caledonian movement. Plenty of bitumen in lower group had showed that there widely developed high quality reservoir rocks and formated paleo-oil pool or paleo-gas pool. The penological and geochemical data had showed that camplicated and multistaged diagenesis and fluid infilling had intimate relationship with formation, preservation and damage mechanism of high quality reservoir rocks. In a word, the controlling factors just for the deep carbonate reservoir rocks were as follows: 1) depositional enviro