摘要
伊犁盆地是在晚海西期褶皱基底上发育的中、新生代山间盆地，侏罗系是其盆地的主体。侏罗纪时盆地水体整体浅而不稳定，除早侏罗世八道湾组沉积期有局部的稳定水体外，其余多为交织河和冲积扇与扇缘辫状河河沼相，煤系地层烃源岩品质普遍较差，暗色泥岩和碳质泥岩一般为中等烃源岩，局部为较好烃源岩；从中生代至新生代，由于地壳厚度不断增大，该盆地整体处于退热型区域大地热流背景场中，属于典型的“冷盆”，有机质热演化普遍处于不成熟到低成熟状态（Ｒｏ为０．４０％－０．７０％）。由于低成熟暗色泥岩生油对成藏的贡献有限，煤岩因其早期生烃组分含量低，产生的烃类最多仅能饱和其微孔的吸附需求，早期排烃对成藏的贡献甚微。伊宁凹陷侏罗系今后的勘探应紧紧围绕沉降中心区，在环生烃中心的构造带上优选圈闭。并加强泥岩低熟油的成烃条件研究与定量评价。
Yili basin is a Mesozoic and Cenozoic intermontane basin developed in lute Hercynianfolded basement with Jurassic as its host. The whole waters in Jurassic basin is shallow and unstable except for local stable waters in Badaowan formation sedimentary Period of Early Jurassic, which is characterized by anastomosing stream, alluvial fan and fan-marginal braided river-swamp factes; commonly Poorquality of hydrocarbon source rocks in the coal measure strata with most medium hydrocarbon source rocksas dark mudstone and carbonic mudstone. From Mesozoic to Cenozoic, the basin lies in terrestrial heat flowsetting of de--heating area with constant increase in crust thickness, belonging to typical 'cold basin', alongwith organic matter thermal evolution ranging from non-maturity to low maturity (R.=0'4%ro.7%). Becauseof limited oil generated from low maturity dark mudstone, component content during early hydrocarbon generation of coal bed in which generated hydrocarbons are only saturated with its micropores, early hydrocarbon now rate has little contribution to formation of reservoirs. It is pointed out that the future explorationshould focus in central subsiding area, select optimum traps in structural belt around the hydrocarbon generation center with caution. Also, we should make further study of the hydrocarbons generated conditionsand quantitative evaluations of the mudstone with low maturity.
出处
《新疆石油地质》
CAS
CSCD
2000年第1期18-22,共5页
Xinjiang Petroleum Geology
关键词
伊犁盆地
生油层
油气勘探
有机质
低成熟油
Yili basin, Jurassic, Coal measure, Source bed, Oil and gas exploration, Organicmatter, Composition, Low maturation crude oil
