The Characteristics of Biomarker Compounds of Source Rocks in Linxi Formation in Guandi Section of Linxi County in the East of Inner Mongolia

Sun Peng;Tang Youjun;Zhang Yongsheng;Peng Yuan;School of Resources and Environment,Yangtze University;

Guandi Section;;Linxi Formation;;Hydrocarbon source rock;;biological marker compound

Linxi Formation was an important position for oil exploration in the periphery of Songliao Basin.Based on gas chromatography and gas chromatography mass spectrometry techniques,the characteristics of biomarker compounds of Linxi hydrocarbon source rocks from Linxiguandi Section in the East of Inner Mongolia were studied,the geological and geochemical significance indicated by sources of organic matter,sedimentary environment,the degree of the thermal evolution of organic matter and some other factors were analyzed.Gas chromatography peaks of saturated hydrocarbons source rocks from Linxi Formation showed"the former peak"of the single peak distribution and the main peak of carbon was composed mainly of C23.This indicates that the main sources of organic matter are mixed organic matter,and Pr/Ph is ranged from 0.04 to 0.26,it presents a strongly reducing sedimentary environment.Molecular fossil assemblages of source rocks in Linxi Formation are abundant in tricyclic terpane with long side chains,it is high level of gammacerane,and the distribution of C27 steranes is dominated.Gammacerane ratio is ranged from 0.12 to 0.16 with an average value of0.14,it reveals that the hydrocarbon source rocks are formed in the environment with micro-saltwater to semi-saltwater.The abundance of C27 steranes is dominated,and the ratio of C27steranes/C29 steranes is 1.13,it show that alga is the main source of hydrocarbon precursor.