Geochemical Characteristics and beginnings of the Rough Oil of Triassic Yanchang Arrangement in Southwestern Yishan Slant

Biomarker compounds derived from early living organisms play an important role in oil and gas geochemistry and exploration since they can record the diagenetic evolution of the parent materials of crude oil and reflect the organic geochemical characteristics of crude oil and source rocks. To offer a scientific basis for oil exploration and exploitation for the study area, the gas chromatography-mass spectrometry method is applied to study the biomarker compounds of crude oil in the Southwestern Yishan Slope of Ordos Basin, through qualitatively and quantitatively analyzing separated materials. The crude oil of the Yanchang Formation and the source rocks of Yan’an and Yanchang Formation were collected in order to systematically analyze the characteristics of the biomarker compounds in saturated hydrocarbon fractions and clarify the organic geochemical characteristics of crude oil. The distribution and composition of various types of hydrocarbon biomarker compounds in crude oil suggest that the parent materials of crude oil are composed of hydration and terrigenous plants, and the crude oil is mature oil which is formed in the weak reducing freshwater environment. Oil source correlation results show that the crude oil of Yanchang Formation in Yishan Slope is sourced from the source rocks of Chang ۷ sub formation.

Keywords:

Crude Oil , Triassic Yanchang , Geochemical evaluation