盐城凹陷烃源岩分析及成藏期次研究

Hydroxide source rock analysis and digenetic stage study of petroleum reservoir in Yancheng depression

应用碳同位素及天然气成熟度经验公式分析气源,确定了天然气成因类型以油型气为主,主力烃源岩层位为上古生界栖霞组。分析该区烃源岩埋藏史类型发现存在晚期深埋型、两期深埋型和早期深埋型三种类型,晚期深埋型最有利于油气二次成藏。对该区流体包裹体有机质丰度及均一化温度分析发现盐城凹陷有过两期油气充注,时间为晚始新世—新第三纪期间的5Ma～11Ma和32Ma～34Ma,以晚期充注成藏为主要特征。

Using carbon isotope and gas maturity to analyze the gas source in Yancheng depression. The authors state that the gas genetic type is petroliferous gas and the predominant hydroxide source rock is from Xixia group of upper Neopaleozoic Erathem. Three types of burial history existed in Yancheng depression： the deep type in late burial history, the deep type in two-step burial history and the deep type in earlier burial history. The late deep burial type is of most advantage to the secondary reservoir formation of oil and gas. Through the study of organic matter abundance and the homogenization temperature of fluid inclusion, the authors find that there are at least two filling processes have occurred and the latter one is more significant. The filling periods are 5 Ma - 11Ma and 32 Ma - 34Ma, respectively.