卡塔克隆起中1井储层沥青地球化学特征与成因

Geochemical Characteristics and Origin of Reservoir Bitumen from Well Zhong 1 in Katake Uplift,Tarim Basin

塔里木盆地海相原油的成因至今仍有争议,而对储层沥青的地球化学特征剖析,能为探索海相原油的成因提供依据。选取卡塔克隆起上的中1井不同层系储层沥青,详尽剖析了其地球化学特征。研究结果揭示,中1井储层沥青的Pr/Ph为1.14～1.39,CPI值1.01～1.08,OEP值0.98～1.05,无奇偶优势或偶奇优势,伽玛蜡烷、C28甾烷丰度低,硫芴系列丰富。甾烷成熟度参数和Ts/(Ts+Tm)均指示中1井储层沥青处于成熟—高成熟热演化范畴。依据特征生物标志物的分布对沥青的成因示踪,中1井储层沥青与上奥陶统烃源岩有成因关系,而中1井储层沥青与塔东2井寒武系原油分子特征的迥异也佐证该认识。

Oil source of marine crude oils from Tarim Basin bitumen may provide a new evidence to elucidate oil source. is still disputed; However, the research on the reservoir Geochemical characteristics of different strata reservoir bitumen from Well Zhongl in Katake uplift are discussed here in detail. Pr/Ph ratios of reservoir bitumens from Well Zhong 1 range from 1.14 to 1.39, CPI ratios from 1.01 to 1.08 which indicate no odd even predominance of normal alkanes, OEP ratios from 0.98 to 1.05. The content of gammacerane and C28 sterane of reservoir bitumens from Well Zhong 1 is low, while dibenzothiophene series are abundant. Sterane isomerization maturity parameter and Ts/Ts ＋ Tm ratio indicate that the degree of maturity of reservoir bitumen from Well Zhongl is mature to high mature. Based on biomarker distribution difference, it is concluded that reservoir bitumen from Well Zhongl of which molecular parameters are contrary to those in Cambrian oil from Well Tadong 2 originated from the upper Ordovician source rock.