摘要
西北地区侏罗纪煤系中主要成烃显微组分是孢子体、角质体、藻类体、沥青质体、碎屑类脂体和基质镜质体等，木栓质体和树脂体等早期成烃组分含量极低。侏罗纪煤系有机质成烃演化特征与一般湖相有机质稍有差异，但基本上仍然遵循一般有机质热降解成熟生油模式，主要生油阶段的Ｒｏ值为０．７％～１．２％，生油高峰Ｒｏ值约为０．９５％。目前西北地区侏罗纪煤系烃源岩Ｒｏ值一般为０．４％～１．３％，多数地区成熟度较低，在山前深坳陷地区成熟度较高，烃源岩Ｒｏ值大于０．７％，进入大量生油阶段，西北地区主要煤系含油气盆地油气田均分布于这些地区，烃源岩成熟度对油气田形成有明显的控制作用。西北地区侏罗系有利的生烃区域基本分布在侏罗纪是沉降、沉积中心而后续埋藏又较深的山前坳陷。图４表１参４５（王孝陵摘）
In the Jurassic coal measure source rocks, main macerals of hydrocarbon generation are sporinite, cutinite, alginite, bituminite, liptodetrinite and desmocollinite. Suberinite and resinite are extremely low concentration, which are generally regarded as the macerals generating hydrocarbon in immature and low mature. The characteristics of thermal evolution of organic matter have some small differences between source rocks from Jurassic measures strata of Northwest China and from non coal forming lacustrine basins, but their models of oil generation are essentially similar. Main oil window of coal bearing organic matter is from 0.7% to 1.2% of vitrinite reflectance, but the peak of oil generation is around 0.95%, and a little earlier than the lacustrine organic matter. In Jurassic basins of Northwest China, the current maturity of organic matter is generally from R o 0.4% to 1.3%, but majority of them has lower maturity. In some piedmont basins or depressions of the area, the organic matter in source rocks has higher maturity, and the vitrinite reflectance ( R o) is great than 0.7%, beginning to generate large amount of crude oil. In the Jurassic coal bearing basins of Northwest China, oil fields generally distribute in these areas having higher mature source rocks. This indicates that maturity of source rocks prominently controls petroleum generation and occurrence of oil fields. The prospective areas of hydrocarbon generation usually locate in the piedmont regions that had been the centers of subsidence and deposition during Jurassic period, and then consequently were deeply buried after Jurassic.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
1998年第5期3-7,共5页
Petroleum Exploration and Development
关键词
侏罗纪
煤系
油气形式
Xibei area, Jurassic period, Coal measures, Organic matter, Oil generation model, Maturation, Reservoir distribution, Piedmont depression
