关键词: 济阳坳陷, 渤南洼陷, 湖相碳酸盐岩, 沉积环境, 微生物, 有机含硫化合物, 成烃模式

Abstract: Lacustrine carbonate source rocks composed of argillaceous limestones, argillaceous dolostones and marls with abundant organic matter were developed in the lower member of Shahejie Formation in Bonan Sag of Jiyang Depression. The macerals are mainly composed of mineral-bituminous matrix and bituminite. The extract has low saturate-to-aromatics ratio and high contents of resin and asphaltene. The carbon skeletons of liquid with several special molecular fossils are well preserved. The organic sulfur compounds with low rearranged compounds are abundant. These characteristics of molecular markers are concerned with the depositional environments. The microbes such as sulfate-reducing bacteria, green sulphur bacteria, and cyanobacteria are the primary bases for generating lacustrine carbonate source rocks. It is suggested that DBT/P value more than one, C₃₅/C₃₄ hopanes value more than one, poor rearranged compounds and rich 30-norhopanes may be the typical markers for judging hydrocarbon generation from carbonate source rocks. The result of oil-source correlation showed that carbonate source rocks had two peaks of hydrocarbon generation and could form large-scale commercial reservoirs. Therefore, it is an important target for oil exploration in Jiyang Depression.

Key words: Jiyang Depression, Bonan Sag, lacustrine carbonate source rocks, depositional environment, microbe, organic sulfur compounds, hydrocarbon generation mode