柴达木盆地石炭系油气调查最新进展

Progress of Carboniferous oil and gas survey in Qaidam Basin

柴达木盆地石炭系是海相油气勘探的新领域,通过对柴达木盆地石炭系油气地质条件进行调查,评价其资源潜力,为该区寻找油气战略接替区提供科学依据。以柴达木盆地石炭系为主要目标,通过调查和研究,首次获得柴达木盆地石炭系油气流,在柴达木盆地古生界海相新层系油气方面取得重要发现;综合区域调查、平衡剖面反演及镜质体反射率等分析,获取柴达木盆地主要构造运动期次;结合盆地模拟技术,重建了石炭系埋藏史,分析了柴达木盆地德令哈坳陷石炭系烃源岩油气地化指标,研究了烃源岩生烃演化史。研究表明:柴达木盆地德令哈坳陷石炭系烃源岩广泛发育,有机质丰度较高,埋深较大,但未发生变质,处于成熟-高成熟阶段;德令哈坳陷石炭系埋藏史主要表现为快速埋藏期、稳定期与强烈抬升剥蚀期,新生代以来沉降史与抬升剥蚀史存在着差异;石炭系烃源岩热演化史主要表现为“存在二次生烃,晚期生烃为主”的特点,主要受该区构造运动控制;柴达木盆地热演化总体表现为缓慢降低的趋势,主要受控于柴达木盆地岩浆热事件与构造活动。调查分析表明,新层系石炭系油气条件良好,资源前景广阔,是柴达木盆地下一步勘探的接替层系。

Carboniferous in Qaidam Basin is a new field for marine oil and gas exploration.Based on the investigation of Carboniferous oil and gas geological conditions,the resource potential is evaluated to provide a scientific basis for seeking oil and gas strategic succession areas.With Carboniferous system in Qaidam Basin as the main target,based on investigation and research,the first carbonaceous oil flow in Qaidam Basin was obtained,and the important discovery of oil and gas in Paleozoic marine strata in Qaidam Basin was obtained.Through comprehensive regional survey,balanced profile inversion,vitrinite reflectance and other comprehensive analyses,the authors assertained the main tectonic movement periods in Qaidam Basin.Through basin simulation techniques,reconstruction of the burial history of Carboniferous system,and analyses of oil and gas geochemical index of Carboniferous source rocks in Delingha depression of Qaidam Basin,the authors studied the evolution history of hydrocarbon generation from source rocks.The results show that Carboniferous source rocks in Delingha depression of Qaidam Basin are widely developed,with high abundance of organic matter and great burial depth without metamorphism,and these rocks are in mature-high maturity stage.The burial history of Carboniferous in Delingha depression is mainly characterized by rapid burial period,stable period and strong uplifting and erosion period.The history of subsidence and uplift-erosion has been different since Cenozoic.The thermal evolution history of Carboniferous source rocks is mainly charactered by“secondary hydrocarbon generation and late hydrocarbon generation”,which is mainly controlled by the tectonic movements in this area.The overall thermal evolution of Qaidam Basin is slowly decreasing,mainly controlled by the magmatic thermal events and tectonic activities in Qaidam Basin.The investigation results show that the new layer of Carboniferous has good oil and gas conditions and broad resource prospects,which is the successive layer for following exploration in Qaidam Basin.