Petroleum potential and development
Section editor – PhD in geology and mineralogy Podolsky Yu.V.
Article # 015
21 p.
pdf  Biogenic carbonate formations on ledges of loosened crystalline rocks as prospective type of combined oil and gas traps
Important morphogenetic type of complex oil and gas traps (reservoirs) is associated with the connection of loosened crystalline and carbonate rocks. Analysis of the distribution, location and patterns of deposit formation of well-known fields in such traps (reservoirs) evidences that this is not a simple parasteresis, but the parageneses as it. The parageneses is caused by the specific diversified role played by the ledges of the crystalline basement both in the localization of biogenic carbonate formations and clastic-carbonate accumulative formations and in their dolomitization. The shelf of the South China Sea is of particular importance for studying the relationship of the Earth foundation’s tectonics, geodynamics, fluid dynamics with biogenic carbonate accumulation and oil and gas deposits formation in complex petrographically-heterogeneous and hydrodynamically-similar reservoirs (traps). In recent years the presence of various bio-carbonate formations has been established within the morphostructures of the Vietnam sector of the South China Sea, where commonly known deposits were once discovered (White Tiger, Dragon etc.) with industrial petroleum potential of granite foundation. The parageneses of granite ledges, clastic arkosic deposite accumulation and reef-carbonate formations is observed on Hainan and other islands. Kuyumbo-Yurubcheno-Tokhomskaya paleorift zone in the joint of the Yenisei Ridge and Siberian platform, confirms the possibility of existence of specific transitional oil-and-gas-bearing horizons between the granite layer of the lithosphere and basal carbonate formations of the stratisphere.
Key words: crystalline rocks, bio-carbonate formation, oil and gas basins.