Geochemical characteristics and their gas and oil source correlation implication in the Tugeerming area of the Kuqa Depression, Tarim Basin, China

Abstract

The Tugeerming area is located in the eastern part of the Kuqa Depression, Tarim Basin. In recent years, prolific oil and gas flow in the Jurassic Yangxia Formation of Well Tudong 2 indicates broad prospects of exploration in the said area. This paper carries out the oil-gas and source correlation in the Tugeerming area. The findings acquired as briefed as follows. The biomarker characteristics of the crude oil of the Yangxia Formation of the Tugeerming Jurassic group showed that the hydrocarbon precursor types were a typical freshwater source of terrestrial organic matters with in the Yangxia Formation. The natural gas of the group is coal-type condensate with associated gas. The maturity of the natural gas is the same as that of the crude oil, where both of them are derived from the same hydrocarbon source rocks. In this paper, the biomarker comparison technique, n-alkane carbon isotope comparison technique, and kerogen carbon isotope-crude carbon isotope comparison technology system were used to study the Jurassic Yangxia Formation oil in the Tugeerming area, as well as the hydrocarbon source rocks of Jurassic and Triassic in the area. The differences between the source rocks are comprehensive. The results show that there is a maternal relationship between the Yangxia Formation crude oil and the source rocks of the Jurassic Yangxia and Kezilenur formations, which provides an important reference for the evaluation of oil and gas resources in this area.