台北凹陷侏罗系油气运聚成藏历史分析

从影响吐哈盆地台台北凹陷油气运聚成藏的古流体动力的分布及其演化特征入手，阐述了流体动力背景下的排烃时期、排烃范围，二次运移方向和有利汇聚区分布，并对该凹陷的成藏历史进行了分析，台北凹陷中，下侏罗统煤系烃源岩的主排烃期分别为早白垩世和上新世至今，且在不同地区二者的发育程度各异，早白垩世中东部排烃率较高，而在上新世以后中西部排烃率较高，该地区流体势分布具一定继承性，分布于高势区之间和外围的相对低势区是油气二次运移的指向区，依据油气汇聚条件，将其划分为最有利，有利与较有利3类。根据生烃与排烃史，流体压力与流体势演化史的发育特点，台北凹陷内大体可划分出两个侏罗系油气成藏期，其一为早白垩世，其二为第四纪，第一成藏期的成藏活动主要发生于凹陷中东部，小草湖，丘东及其周围地区应是当时油气运移的指向及最有利的聚集地区；第二成藏期内活跃的成藏作用主要发生在中西部地区，东部的古油气藏将受到一定程度的改造与补充。图5参11（王震亮摘）。

An analysis for oil and gas migration and accumulation history in Jurassic system, Taibei sag, Turpan-Hami basin

On the basis of distribution and evolution of paleo-hydrodynamic influencing hydrocarbon migration and accumulation, it is set forth about periods, scopes of expulsion from source rocks, directions of secondary migration and the distribution of profitable convergence areas in reservoir rocks, and the history of accumulation and pooling in Taibei depression is analyzed and summarized. It is discovered, the main periods of expulsion in coal-measure source rocks of lower and middle Jurassic series is early Cretaceous epoch and Pliocene up to now respectively, and the high efficiency of expulsion in middle and eastern areas is developed during early Cretaceous epoch, in contrast, in middle and western areas is Pliocene up to now. The distribution and evolution of fluid potential is of succession. By the way, the relatively low potential areas among high potential areas and those parts located in periphery of high potential areas are directions of secondary migration, and the former is divided into three types-most profitable, profitable and fairly profitable, based on the conditions of migration and accumulation. According to the history of hydrocarbon generation and expulsion, evolution of fluid pressure and fluid potential, the behavior of hydrocarbon in Jurassic system is divided into two major phases of accumulation and pooling in Taibei depression, i.e. phase of early Cretaceaous epoch and Quaternary Period respectively. During the first accumulation stage, the behavior of hydrocarbon is mainly occurred in middle and eastern part of the depression, and the directions of secondary migration and most profitable accumulation areas are Xiaocaohu, Qiudong and their adjacent areas, where at second accumulation stage, active accumulation is mainly developed on middle and western part, and the former existed oil and gas pool is to be remold and complement to some extent.