柯克亚气田的油气成因复杂,对原油和可能烃源岩的分子标志物特征进行了剖析,在凝析油中检测到3-甲基甾烷,不含4-甲基甾烷,富含重排藿烷和C30-未知萜烷,表明油源主要来自于二叠系源岩.柯克亚的天然气重烃含量高,属湿气,乙烷碳同位素偏重;天然气氩同位素和成熟度特征均指示混源气特征,通过气源判识天然气主要来源于石炭系-二叠系源岩,部分来源于侏罗系源岩.天然气的乙烷δ13C值明显重于凝析油全油δ13C值,揭示柯克亚地区凝析油和天然气分属不同来源.

It is controversial where the hydrocarbon in Kokyar Condensate Field derived from. Correlating the characteristics of biomarkers from the Tertiary condensate oil with the possible source rocks, the result indicates that the condensate gas mainly originates from Permian hydrocarbon source rock due to existing 3-methylsterane, relatively high abundance of diahopane and unknown C30-terpane but no 4-methylsterane in the condensate oil. The natural gas in the field is wet gas for the abundance of heavy hydrocarbon is high and the carbon isotope values of ethane are heavy. Both of argon isotope and maturation indicate that the gas did not come from a single source. It is pointed out that the gas originates mostly from Carboniferous-Permian rock and partly from the Jurassic rock. Thus, the condensate and gas in Kokyar Field derive respectively from different source for carbon isotope values of ethane in gas are obviously heavier than those in whole condensate oil.