摘要
三塘湖盆地目前所发现的原油的C2 9甾烷 2 0S/ (2 0S +2 0R)值大部分小于 0 .42 ,属于低 (未 )熟油的范畴。与国内外报道的低熟油相比 ,三塘湖盆地物性特征也具有高密度、高粘度及高含蜡量等特征 ,但其物性偏好。经油源分析 ,这些低熟油主要来源于上二叠统芦草沟组。该组烃源岩演化程度较低 ,有机质丰度较高 ,属较好生油岩。通过有机显微组分分析 ,发现芦草沟组烃源岩以富含腐泥无定形富氢显微组分而有别于三塘湖盆地其它低熟源岩。经热解分析 ,腐泥无定形是芦草沟组烃源岩主要生烃贡献者 ,并且其主生烃期Ro 在 0 .35 %～ 0 .6 %之间。因此 ,腐泥无定形低熟生烃是三塘湖盆地低熟油的主要生烃机制。另外 ,在三塘湖盆地原油以及芦草沟组源岩中都检测到 17α(H) 2 5 降霍烷系列化合物 ,说明三塘湖盆地的低熟油可能与陆源有机质细菌降解改造作用有关。
Most of the oils found in Santanghu basin were regards as immature, mainly because the values of 20 S /(20 S +20 R ) of C 29 sterane are lower than 0.42. Compared with other immature oils reported in china, they have some special characteristics. Through analyzes to oil source, these immature oils mainly come from Lucaogou Formation of upper Permian which is better source rocks with low maturity and much abundance of organic matter. Different from other immature source rocks in Santang lake basin, Lucaogou formation abounds with sapropelic amorphous that content abundant hydrogen. It can be learned through pyrolysis that the sapropelic amorphous is the main contributor of hydrocarbon in Lucaogou formation and the R o of its main hydrocarbon generating interval is from 0.35% to 0.6%, which is the main hydrocarbon generating mechanism of the immature oils in Santang lake basin. Furthermore, The series of 17α(H)-25-norhopane compound was found not only in oil, but also in Lucaogou formation, which hints that the immature oils in Santang lake basin may have relations with the bacteria degradation of terrigenous organic matter.
出处
《沉积学报》
CAS
CSCD
北大核心
2001年第4期598-604,共7页
Acta Sedimentologica Sinica
