Abstract:

Qaidam Basin is the one of the large petroliferous basins in the western China, and the hydrocarbons have been found mainly in the Mesozoic and Cenozoic strata. Recent studies have shown that the Carboniferous is one of the main source rocks in Qaidam Basin. The discovery of oil seepage and the similar characteristics of biomarkers with the carboniferous source rock show that the Qaidam Basin has large Carboniferous hydrocarbons resource potential and serves as a new strata and area for strategic breakthrough in hydrocarbons resources exploration. The number of wells that drilled into the Carboniferous strata in the Qaidam Basin is small, and the parameters of outcrop samples were used in the Carboniferous resource evaluation. Outcrop samples generally have undergone weathering, which have impact on the abundance of source rock. In this paper, through detailed comparison of outcrop and core samples to determine the factors of weathered hydrocarbon source rocks in North Margin of Qaidam Basin, and restore organic matter abundance of outcrop source rocks by weathering factor. After recovery, the outcrops of Carboniferous in the North Margin of Qaidam Basin are middlegood source rocks.

Key words: weathering factor, restoration of organic carbon, Carboniferous, North Margin of Qaidam Basin