摘要
麻江古油藏是中国南方最大的海相古油藏之一,但目前关于其成藏的时间尚没有统一的认识。在本次研究中,详细分析了储层沥青的地球化学特征及其成因,以此为基础,对麻江古油藏的成藏期次进行了探讨。研究表明,储层沥青的饱和烃色谱图正构烷烃分布完整,但基线明显上凸且存在25-降藿烷,这揭示出麻江古油藏至少存在两期原油充注;奥陶系-泥盆系储层沥青来自相同的烃源岩,表明该区最大规模的原油充注发生在泥盆系沉积之后。应用储层流体包裹体测温与自生伊利石钾氩法定年,结合烃源岩的热演化史进行了成藏期次研究。结果表明,麻江古油藏经历了加里东晚期的小规模成藏及破坏、海西期大规模油气成藏、印支期油气转化及燕山期大规模破坏的演化过程,其中海西期是其主要成藏期。
Majiang paleo-oil reservoir is one of the largest marine paleo-oil reservoirs in South China. There is debate about its forming time. This paper investigates the hydrocarbon accumulation period by analyzing the geo- chemical characteristics and genesis of reservoir-bitumen. The study shows that the distribution of n-alkanes of saturated hydrocarbon chromatogram from the reservoir-bitumen is complete, but the base line is up convex, and 25-norhopane exists. It indicates that crude oil charging occurred at least in two stages in this paleo-oil reservoir. The reservoir-bitumen in Ordovician and Devonian originated from the same source rocks, indicating that the massive crude oil charging occurred after deposition of the Devonian. Reservoir-fluid inclusion thermometry and K-Ar dating of autogenous illite, in combination with thermal history of source rocks, were used to investigate the hydrocarbon accumulation phases. The results shows that Majiang paleo-oil reservoir experienced small-scale hy- drocarbon accumulation and damage during the Late Caledonian time,large-scale hydrocarbon accumulation dur- ing the Hercynian time, oil-gas conversion in the IndoChinese time, and large scale damage during the Yanshan time, and the Hercynian time is suggested as the main accumulation stage of Majiang paleo-oil reservoir.
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2012年第3期417-423,共7页
Oil & Gas Geology
基金
石油化工联合基金项目(40739904)
中国石化科技部项目(YPH08073)
关键词
储层沥青
地球化学
成藏期次
麻江古油藏
贵州
中国南方
reservoir-bitumen, geochemistry, hydrocarbon accumulation phase, Majiang paleo-oil reservoir, Guizhou, South China
