Characteristics and Genetic Analysis of Crude Oil in the Volcanic Reservoir of Oulituozi Area
欧利坨子火山岩油藏原油特征及成因分析

Volcanic activities might exert important effects on the evolution of oil sources.In this paper,the authors studied geochemical characteristics of oil in Oulituozi area of Liaohe Oilfield,and demonstrated that different distances between the reservoirs and the crater may result in different geochemical properties of crude oil.The stable carbon isotopes of saturated hydrocarbon and specific compound composition of the oil from the trachyte near the crater are relatively low,and the negative anomalies of the isoprenoids disappear.The oil has lower values of CPI and OEP,with the averages being 1.26 and 1.06,respectively.There are good indications of oil and gas in volcanic reservoirs,and commercial oil flows can be obtained in some wells.Nevertheless,there exist great differences in the development results of these reservoirs.The influence that volcanic activities impact upon the sources near the crater cannot be ignored.The relatively shallow volcanic reservoirs were mainly filled with oil generated rapidly from interactions between the volcanic activities and the sources.The deep volcanic reservoirs,which were affected by volcanism and also filled with non-conventional oil and gas,contained oil generated by the sources which experienced normal evolutions.