滨里海盆地南部隆起带盐下层系油气成藏主控因素

Controlling Factors of Petroleum Accumulation in Pre-Salt Strata in South Uplift of Pre-Caspian Basin

滨里海盆地南部隆起带盐下层系油气成藏条件优越,中泥盆统—上石炭统发育2套优质烃源岩、3套储集性能良好的碳酸盐岩储集层。从区域构造沉积演化入手,据最新钻井资料,对南部隆起带盐下层系的油气地质条件、成藏主控因素进行研究后指出,烃源岩的分布和成熟度控制了现今"西气东油"的分布格局;大型古隆起构造控制了碳酸盐岩和礁体的发育;风化淋滤作用改善了维宪阶—巴什基尔阶碳酸盐岩储集层的储集性能,控制着油气的富集。

The pre-salt strata in south uplift of Pre-Caspian basin is of advantageous conditions for hydrocarbon accumulation. Two sets ofhigh quality source rocks and three sets of carbonate reservoirs with good reservoir properties are found in its Middle Devonian-Upper Car-boniferous. This paper studied its petroleum geological conditions and reservoir-forming controlling factors, in view of the regional structureand sedimentary evolution integrated with the latest drilling data. The result shows that the distribution and maturity of the source rockscontrol the framework of＂gas in the west and oil in the east＂in this area; the large-scale paleo-uplift belt controls the development of thecarbonate rocks and reefs, and the weathering leaching effect greatly improves the reservoir property in the carbonate reservoir of the Visean-Bashkirian（KT-2）, which control the hydrocarbon accumulation.