新构造运动对塔里木盆地油气成藏模式的影响

The Influence of Neotectonic Movement on Hydrocarbon Accumulation Patterns in Tarim Basin

印度次大陆与欧亚大陆碰撞的远距离构造效应,打破了塔里木盆地古近纪末的构造平衡。经古构造恢复,推断出塔里木盆地古近纪以来各区域的变化特征:塔西南麦盖提斜坡向北迁移且南北宽度增加;巴楚隆起南部变为斜坡区且宽度缩小;塔北隆起整体向南迁移;塔东满加尔凹陷北部萎缩,南部和东南边界向外扩展;塔中隆起范围明显缩小;塔东南隆起构造规模逐渐缩小但幅度增加。受新构造运动的影响,不同区域的油气表现为不同的晚期成藏模式,塔西南巴什托普油田以群5井区为支点地层翘倾,同一构造单元内不同圈闭此消彼长,形成"消长式汇合型"成藏模式;塔北哈得逊油田石炭系整体反转,构造高点向南迁移,正常温压下油水界面倾斜,形成"驿站式输送型"成藏模式;塔中4油田表现为老断层阶段式复活,多个油气水界面共存,形成"渗漏式残存型"成藏模式。油气聚集表现为阶段式平衡或阶段式调整的非稳态特征。研究油气在新构造运动期调整特点,对塔里木盆地油气勘探具有重要意义。

The remote tectonic effect resulted from collision between the Indian subcontinent and the Eurasian continent broke the structural equilibrium state at the end of the Paleogene in Tarim basin. With the method of paleo-structural restoration, this paper estimated the regional changing characteristics of Tarim basin since Paleogene as follows： The Maigaiti slope in southwestern Tarim basin migrated northward, increasing the width of the north and south; the south part of Bachu uplift became slope area and width narrowed; Tabei uplift migrated southward on the whole; the Manjiaer sag in eastern Tarim basin shrank northward, while the south and southeast boundaries extended outward; the range of Tazhong uplift became obviously narrowed; Tadongnan uplift＇ s structural size became gradually smaller but its amplitude increased. Having influenced by the neotectonic movement, the hydrocarbons in different regions showed different oil and gas accumu- lation patterns. The Bashituopu oilfield in southwestern Tarim basin tilted with a fulcrum of Qun-5 well area. Different traps in the same tec- tonic unit were shifted, forming the hydrocarbon accumulation pattern of ＂the ebb and flow type of convergence＂; the Carboniferous strata in Hudson oilfield in northern Tarim were reversed on the whole, with structural highs migrating southward, which made oil-water interface tilt under normal temperature and pressure, forming ＂post conveyor type＂ oil-gas accumulation pattern; the old faults in Tazhong-4 oilfield revived episodically, with multiple oil-gas-water interfaces, forming ＂residual leakage type＂ accumulation pattern. The oil and gas accumulation kept in unsteady state characteristics of episodic balance and adjustment. Research on hydrocarbon＇ s adjustment characteristics in the neotectonic period has a guiding significance on the petroleum exploration and development in Tarim basin in the future.