鸡西盆地下白垩统煤系烃源岩生物标志物地球化学特征

GEOCHEMICAL CHARACTERISTICS OF BIOMARKERS EXTRACTED FROM THE LOWER CRETACEOUS COAL MEASURES ROCKS IN JIXI BASIN

高福红 高红梅 樊馥

Gao Fuhong Gao Hongmei Fan Fu

吉林大学, 地球科学学院, 长春, 130061

College of Earth Science, Jilin University, Changchun, Jilin 130061, China

应用气相色谱和色谱—质谱等分析方法,对鸡西盆地下白垩统煤系烃源岩的泥岩和煤岩生物标志物进行研究。结果表明,泥岩正构烷烃为前高单峰型,主峰碳为C16或C18,Pr/Ph分布于1.16-2.90,Pr/nC17大于1;煤岩正构烷烃为后高单峰型,主峰碳为C23或C22,Pr/Ph分布于2.86-11.22,Pr/nC17为2.1-3.33;泥岩和煤岩OEP和CPI值集中在1.0附近,已进入成熟阶段。生标中泥岩三、四环萜烷/C30藿烷比值为2.37-3.62,C3122S/22(S+R)值为0.57-0.61,Ts/Tm为0.47-0.81,γ-蜡烷/C30藿烷为0.11-0.34之间,规则甾烷内ααα20R构型呈"V"型分布,母质来源以水生生物为主,形成于还原环境,沉积介质咸化程度高,有利于有机质的保存和转化;煤岩三、四环萜烷/C30藿烷比值低于泥岩,C3122S/22(S+R)值在0.6附近,Ts/Tm和γ-蜡烷/C30藿烷值极低,规则甾烷ααα20R构型分布呈反"L"型,母质来源以高等植物为主,形成于氧化环境,经历了较强的降解作用。

By the Gas chromatography and the Gas chromatography-mass spectrogram analysis,the biomarkers in the Lower Cretaceous mud rocks and coals of coal measures from Jixi Basin were studied.The results indicate that n-alkanes in mud rocks show front single-peak type,with the main peak carbons to be C16 or C18.The ratio of Pr/Ph is 2.86～11.22,Pr/n C17 is larger than 1.The n-alkanes in coals show rear single-peak type,with the main peak carbons to be C22 or C23.The ratios of Pr/Ph and Pr/n C17 are 2.86～11.22 and 2.1～3.33 respectively.The values of the OEP and CPI in both mud rocks and coals concentrale on 1.0.The thermal evolution has reached maturation stage.The biomarkers in mud rocks show that the ratio of tricycle terpane plus tetracyclic terpane to C30H is 2.37～3.62.The C3122S/22(S+R),Ts/Tm and G/C30H are 0.57～0.61,0.47～0.81 and 0.11～0.34 respectively.The ααα20R homosteranes in mud rocks appears to be in asymmetrical "V"distribution.The analytic result of the biomarkers show the mud rocks coming mainly from aquatic organisms and depositing in reducing environment with more saline water,which is better for preservation and transformation of organics.The biomarkers in coals show that the ratio of tricycle terpane plus tetracyclic terpane to C30H is lower than that in mud rocks.The ratio of C3122S/22(S+R) is about 0.6,the Ts/Tm and G/C30H are very low.The ααα20R homosteranes of coals appear to be in inverted "L" distribution.The coals are mainly from higher plants,and deposit in oxidizing environment.

国家油气资源战略选区专项(XQ-2004-07)

https://doi.org/10.11781/sysydz200702188