塔里木盆地寒武系超深层含油气系统盆地模拟

针对塔里木盆地寒武系超深层含油气系统复杂的成藏特征,采用动力学模拟技术探讨了寒武系"源-圈-藏"的演化过程,揭示了超深层含油气系统油气"生成-运移-聚集-调整"的演化历史。塔里木盆地台盆区烃源岩的生烃史模拟显示:下寒武统烃源岩的热演化存在4个关键时刻,分别为加里东中期、加里东晚期—海西早期、海西晚期、喜马拉雅晚期;发育3种热演化模式,即盆地坳陷区持续热演化模式、盆地斜坡区接力热演化模式和盆地周缘山前带快速热演化模式。烃源岩的成熟度恢复显示:塔北斜坡带、顺托果勒低隆起和麦盖提斜坡带烃源岩的整体成熟度低于2%,处于高成熟阶段,目前仍然具有较好的生烃潜力。超深层含油气系统的混合流模拟表明:加里东期和海西期断裂对塔里木盆地原生油气藏的运聚较为重要,而喜马拉雅期断裂对次生油气藏的运聚影响较大。塔里木盆地台盆区寒武系上、下两套含油气系统流体的流线变化和运聚趋势具有明显的继承性,隆起带和斜坡区的优势运移通道是油气运聚的有利区,其中,卡塔克隆起和巴楚隆起西侧具有多源充注汇聚的特征,巴楚隆起东侧和塔北隆起受单一含油气系统持续充注,是较有利的油气富集区。盆地模拟对塔里木盆地超深层含油气系统的研究具有一定的参考价值,值得进一步探讨完善。

Basin modeling of Cambrian ultra-deep petroleum system in Tarim Basin

To make clear the complex accumulation and evolution process of the Cambrian ultra-deep petroleum system in Tarim Basin, this paper explores the evolution process of Cambrian "source-trap-reservoir" by using dynamic simulation technique, and reveals the evolutionary history of "generation-migration-accumulation-adjustment" of the ultra-deep petroleum system. The simulation of the hydrocarbon generation history of source rocks in the platform-basin transitional area of Tarim Basin shows that there are four key periods in the thermal evolution of Lower Cambrian source rocks, i.e., Middle Caledonian, Late Caledonian to Early Hercynian, Late Hercynian and Late Himalayan. Three thermal evolution patterns were developed, i.e., continuous thermal evolution pattern in depression belt, continuous thermal evolution pattern in slope belt, and rapid thermal evolution pattern in piedmont belt. The maturity recovery of source rocks shows that the source rocks in Tabei slope belt, Shuntuoguole low uplift, and Maigaiti slope belt have an overall maturity of less than 2%, indicating a high maturity stage, and now still has good hydrocarbon generation potential. The simulation of mixed flow in the ultra-deep petroleum system shows that the Caledonian and Hercynian faults play an important role in the hydrocarbon accumulation and migration in primary oil-gas reservoirs in Tarim Basin, and the Himalayan faults has a great impact on the hydrocarbon migration and accumulation in secondary reservoirs. The streamline variation and accumulation trend of fluid flow in Upper and Lower Cambrian petroleum systems in platform-basin area of Tarim Basin show obvious inherited characteristics. The dominant migration pathways in uplift belts and slope belts are favorable areas for hydrocarbon migration and accumulation. Among them, the Katake uplift and the west of Bachu uplift have the characteristics of multi-source charging and accumulation; the east of Bachu uplift and the Tabei uplift were continuously charged by single petroleum system, thus being a favorable hydrocarbon accumulation area. Basin modeling has a certain reference value for the study of the ultra-deep petroleum system in Tarim Basin, which is worthy of further exploration and improvement.