塔里木盆地跃满地区超深油藏成藏地质条件与演化过程

塔里木盆地台盆区深层海相碳酸盐岩在7 000 m以深持续发现大型油气聚集，但由于其复杂的地质结构与演化特征，仍需进一步加强油气成藏研究。位于塔北隆起西南部围斜的跃满地区发现了埋深在7 100~7 600 m之间的超深油藏，通过对该油藏的地质—地球化学综合分析，厘定了超深油藏成藏的有利条件：深大断裂一方面控制了岩溶作用的发生，导致一间房组大规模层间岩溶的发育与断溶体圈闭的形成、并与上覆吐木休克组和桑塔木组有效盖层组成了有利的储盖组合；另一方面作为流体运移的优势通道，为来自寒武系—奥陶系烃源的油气运移提供了便利条件；油气成藏后在低地温梯度和晚期快速深埋条件下，由于时间与温度的补偿效应不足，原油未发生裂解，以单一油相保存。跃满地区超深油藏成藏演化过程揭示了深层仍具有巨大的液态石油勘探潜力，勘探目标以具有串珠状强反射的断溶体油气藏为主。

Geological conditions and evolution for the accumulation of the ultra-deep oil pools in the Yueman area,Tarim Basin

Large-scale of petroleum accumulations are continuously discovered in deep marine carbonates with depth over 7000 m in the cratonic area of the Tarim Basin, however, the research on the petroleum accumulation needs further enhancement due to the complex geology and evolution characteristics. Ultra-deep oil pools were discovered within an interval of 7 100-7 600 m in the Yueman area, which is located in the slope area of the southwestern Tabei Uplift. Based on the comprehensive geological-geochemical analysis of these oil pools, the favorable conditions for the accumulation of deep petroleum were unraveled. The major faults on the one hand controlled the karstification of carbonates and led to the development of fault-karst carbonate reservoirs in the Yijianfang Formation, and thus formed favorable reservoir-seal assemblage in combination with the overlaid valid seals from the Tumuxiuke and Sangtamu formations; on the other hand, the major faults served as favorable migration pathways for the deep fluids, especially for the migration of oil and gas from the deep Cambrian-Ordovician source rocks. Under the background of both relatively low geothermal gradient and rapid burial process during the late period after petroleum accumulation, the petroleum did not undergo cracking and remained in the single liquid phase due to the insufficient compensation of temperature with heating time. It can be therefore indicated from the petroleum accumulation process in the Yueman area that, there remains great potential for liquid petroleum exploration in deep strata, and the future exploration targets should be the fault-karst carbonate reservoirs with strong bead-like reflections.