吐哈盆地台北与台南凹陷三叠系成藏差异性

分析了台北凹陷鄯深构造和台南凹陷鲁克沁构造带之间三叠系储集层特征及其控制因素以及成藏机理的差异性,认为造成这种差异的最根本原因是它们在晚印支运动期到晚燕山运动期乃至晚喜马拉雅运动期所处的构造环境不同。尽管台北凹陷的古隆起构造带(如鄯善弧形带)紧邻烃源岩,但由于受成岩作用和构造变化两方面的影响,存在储集物性较差、圈闭形成相对滞后于烃源岩生排烃高峰期的风险;而台南凹陷在侏罗纪早期埋藏较浅,成岩压实作用较弱，具有较好的储集物性,同时从晚印支运动期开始，台南凹陷东南方向构造开始稳定持续抬升，为油气运移的长期指向区。因此,台南凹陷相对于台北凹陷具有更好的成藏条件,吐哈盆地三叠系的勘探应该关注构造相对稳定，并有油气供给的盆地南带。

Differential Hydrocarbon Accumulation of Triassic in Taibei and Tainan Sags, Tuha Basin

The reservoir characteristics of Triassic between Shanshen structure belt in Taibei sag and Lukeqin structural belt in Tainan sag as well as their controlling factors are analyzed. The differential mechanism in hydrocarbon accumulation is due to their different structural settings in Late Indosinian movement, Late Yanshan movement till Late Himalayan movement. The paleo-uplift structural belt (i.e. Shanshan arcuate zone) in Taibei sag is adjacent to the source rocks, but for diagenesis and tectonic variation, the differential reservoir quality and trap shape timing behind hydrocarbon generation and expulsion periods occur; while the relatively shallow deposits of Early Jurassic in Tainan sag have better reservoir quality for its weak diagenesis and compaction. Also, since Late Indosinian movement, the structures in the southeastern Tainan sag commence stable and continuous tilting, thus being the long-term directional domain. Therefore, the petroleum exploration of Triassic in Tuha basin should pay more attention to the southern area with relatively stable structures, hydrocarbon supply and better reservoir quality.