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研究了吐哈盆地低演化烃源岩有机质受到细菌微生物改造后其生物标志物的分布特征。结果表明:低演化有机质在经受细菌微生物作用时不同系列生物标志物的降解敏感性存在“类阶梯式”序列:正构烷烃>无环类异戊二烯烷烃>藿烷>甾烷>芳香烃。甾烷C29αββ/(ααα+αββ)和芳烃9-MP/ΣMP是良好的细菌微生物作用有机质的敏感参数。同一烃源岩有机质的生物标志物参数出现:OEP2>OEP1(OEP1可能出现偶碳优势);藿烷C31αβ22S/22(S+R)>甾烷C29ααα20S/20(S+R);及甾烷C29αββ/(αββ+ααα)>C29ααα20S/20(S+R)等异常组合特征,可认为该源岩经历过较强烈的微生物作用过程,其降解程度可用每对参数比值的大小来判识,进而可将这些异常生标组合特征作为判识该地区有无微生物成烃(气、油)的依据。研究区源岩被微生物改造后改变了原始有机质的性质,使其生烃活化能大大降低,在低演化阶段即可生烃,从而有利于低熟油、气的生成。
The distribution characteristics of biomarkers of organic matter in low-evolution source rocks in the Turpan-Hami basin after the microbial transformation were studied. The results showed that the degradation sensitivity of different series of biomarkers in the presence of low-level evolutionary organisms was “ladder-like”: n-alkanes> acyclic isoprenoids> hopanes> steranes> Aromatic hydrocarbons. Sterane C29αββ / (ααα + αββ) and aromatics 9-MP / ΣMP are sensitive parameters for good bacterial organism. The biomarker parameters of organic matter in the same source rock are as follows: OEP2> OEP1 (OPOC1 may have the advantage of even carbon); hopane C31αβ22S / 22 (S + R)> sterane C29ααα20S / 20 / (αββ + ααα)> C29ααα20S / 20 (S + R), and so on. It can be considered that the source rock has experienced a more intensive microbial process and the degree of degradation can be judged by the ratio of each pair of parameters, These abnormal biomarker combinations are used as a basis for identifying whether there is any microbial hydrocarbon (gas, oil) in the area. The source rock of the study area was transformed by microorganisms and changed the nature of the original organic matter to greatly reduce the activation energy of hydrocarbon generation. Hydrocarbon generation can be carried out in the low evolution stage, which is beneficial to the formation of low-mature oil and gas.