黔中隆起北缘金沙岩孔古油藏特征及成藏期次厘定

Paleo-oil Reservoir Characteristics and Hydrocarbon Accumulation Period Redefinition of Jinsha Yankong in North Margin of the Central Guizhou Uplift

为了了解南方海相古油藏特征及其成藏期次，对金沙岩孔古油藏进行了系统的解剖．运用BasinMod盆地模拟软件和均一法测温及激光拉曼探针等微观技术，模拟烃源岩成熟演化史及生排烃史，确定了流体包裹体类型、古油藏油气充注期及成藏期次．结果表明：金沙岩孔剖面油气显示明显、具有良好的储集性能、存在2套优越的生储盖组合；包裹体烃类成分以CH4为主，具明显干气特征，部分包裹体内含CO2；古油藏存在3期油气充注，构成105～115℃，125～135℃，145～155℃这3个峰簇，分别相当于生油-主生油过渡期、主生油期及湿气主生期。黔中下寒武统烃源岩主要生排烃期有3期，分别对应早泥盆世末期、晚三叠世早期和晚侏罗世末期，为主要的古油藏成藏期，与由流体包裹体均一温度反映的油气充注期相对应．

To identify features of Southern marine paleo-oil reservoirs and their hydrocarbon accumulation period, the Jinsha Yankong paleo-oil reservoir was systematically dissected. Based on the BasinMod analysis software, homogenization temperature measurement and Raman spectrum technologies, the generation and expulsion history of source rock were simulated. The types of fluid inclusions, hydrocarbon charging stages and reservoir-forming periods were identified. The results show that Jinsha Yangkong profile takes on clear sign of oil and gas, good reservoir property, and two sets of favorable source-reservoir-cap assemblage. The hydrocarbon in the fluid inclusions is a dry gas mainly composed of CH4 and some contain CO2. The paleo-oil reservoir has three times of hydrocarbon filling, forming 105-115 ℃, 125-135 ℃ and 145-155 ℃ clusters, which are corresponding to the periods of oil generating-main oil generating, main oil generating and main moisture generating, respectively. The lower Cambrian source rock in central Guizhou has three times of hydrocarbon generation and expulsion, which are main accumulation periods and corresponding to late Early Devonian, early Late Triassic and late Late Jurassic, respectively. The times are keeping the same step to the hydrocarbon charging stages reflected by the homogenization temperature of inclusions.