塔里木盆地顺托果勒地区志留系油藏形成模式探讨

Physical simulation and discussion of the formation mode of the Silurian oil reservoirs in the Shuntuoguole region, Tarim Basin

  • 摘要: 基于塔里木盆地顺托果勒地区S9油藏形成过程的物理实验模拟,探讨了该区志留系柯坪塔格组下段油气成藏模式:寒武系-奥陶系烃源岩为油气源,断裂带为主要输导体,且活动期主要为志留纪晚期和二叠纪2期,也是2期主要成藏期。物理模型结构与研究区S9油藏目标层段的地质结构相似。设计了下部充注、断层输导、连续稳态与幕式充注的物理模拟实验。其中油气充注以幕式充注为主,设计5,10,15 MPa等3种充注压差;稳态充注为辅。断层设计了2种物性(高渗透率和低渗透率)与变渗透性(相对封闭)2种形式。研究断层物性、充注压差、充注方式变化对油运移路径和聚集量的影响,分析2个主要成藏期地质过程中的必要条件。结果表明,顺托果勒地区志留系柯坪塔格组下段储层具有志留纪-泥盆纪与二叠纪-三叠纪2期叠加成藏富集条件,存在早期大规模成藏聚集的可能性。

     

    Abstract: Physical simulations were carried out with the S9 reservoir in the Shuntuoguole area of the Tarim Basin to study the hydrocarbon accumulation pattern in the lower section of Silurian Kalpintag Formation. Hydrocarbon mainly originated from the Cambrian-Ordovician source rocks. Faults provided pathways for hydrocarbon migration, and were most active during the late Silurian and Permian, which matched with two accumulation stages. A physical model was made according to the geologic structure of target section in S9 reservoir. Hydrocarbon was injected from the bottom of the model by continuous and steady or intermittent way, and then migrated upwards through faults. We mainly used the intermittent injection, and carried out simulations at pressure differences of 5,10,15 MPa. The faults with high, low and flexible permeability were applied in the simulation. The controls of fault property, pressure difference and injection way on hydrocarbon migration and accumulation were discussed, so as to study the necessary geologic conditions during hydrocarbon accumulation stages. The results showed that the lower section of the Silurian Kalpintag Formation was enriched with hydrocarbon during the Silurian-Devonian and Permian-Triassic, indicating for a possibility of early and large-scale reservoir.

     

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