摘要
通过对焉耆盆地烃源岩的生烃史、油气成熟度、流体包裹体均一温度和储集层自生伊利石同位素年代学的研究 ,综合分析盆地的成藏期次。焉耆盆地八道湾组烃源岩的两次主要生、排烃作用发生在侏罗纪末期和早第三纪 ,白垩纪为生烃停止期 ;三工河组砂岩溶蚀孔隙中的流体包裹体形成温度主要为 10 1～ 13 0℃ ,与侏罗纪晚期三工河组储集层温度相当 ,表明这些包裹体主要是侏罗纪晚期以压溶和溶蚀作用为主的晚成岩作用阶段形成的。储集层自生伊利石的K/Ar同位素年龄分布主要为 170～ 14 0Ma和 12 0～ 10 0Ma ,第一期反映侏罗纪晚期的成藏作用 ,第二期与白垩纪油气藏的破坏作用有关。三工河组原油、八道湾组原油的αααC2 9甾烷 2 0S/ (2 0S + 2 0R)比值平均为 0 .49和 0 .45 ,C2 9甾烷 ββ/ (αα + ββ)比值平均为 0 .46和 0 .40 ,表明原油生成和成藏时烃源岩的Ro 值约为 0 .7%～ 1.0 % ,与生烃凹陷八道湾组烃源岩在侏罗纪末的成熟度相当 ;天然气甲烷碳同位素值为 -5 1.80‰～ -4 1.5 3‰ ,成熟度比原油更低 ,形成时间更早。综合分析认为 ,焉耆盆地曾发生两期成藏作用 ,第一期是侏罗系埋深最大的侏罗纪晚期 ,为主要成藏期 ;第二期是侏罗系二次埋藏的第三纪。图 4参
The time of petroleum accumulation in Yanqi basin, Northwest China is determined according to the studies of hydrocarbon generation history of source rock, oil and gas maturity, homogenization temperature of fluid inclusion and K/Ar dating of illite in reservoir. The source rock of Badaowan Formation of Lower Jurassic has two main generation periods in geologic time, with one in the late Jurassic and the other in late Tertiary. The fluid inclusions mainly occurred in the dissolution or pressure solution pores of sandstone reservoir, the homogenization temperature of which is 101-130℃, suggesting that the fluid inclusions were mostly formed in late diagenesis stage in late Jurassic. K/Ar dating shows that the ages of the very fine grained illite fall in two time intervals, 170-140Ma and 120-100Ma, indicating the time of petroleum entrapment in late Jurassic and the time of destruction of petroleum accumulation in the tectonic event in Cretaceous respectively. The maturity indices of biomakers from oil also show that the maturity of source rock when the oil was generated is equivalent to the vitrinite reflectance value of 0.70%-1.0%, the maturity of Badaowan source rock in the end of Jurrassic. In summury, there are two peroids of oil and gas entrapment in Yanqi basin, with the main peroid in late Jurassic and the other in late Tertiary.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2002年第1期69-71,共3页
Petroleum Exploration and Development
关键词
焉耆盆地
八道湾组
烃源岩
生烃史
油气成藏期次
Yanqi basin
Badaowan Formation
source rock
hydrocarbon generation history
period and times of oil and gas accumulation
