塔里木盆地成藏系统分析

塔里木盆地为一多成藏系统盆地,同一含油气系统往往存在多个成藏系统。在克拉通区,轮南成藏系统实际上包括了3个成藏子系统,即奥陶系常压开放型原生—次生油气藏成藏系统、石炭系超压半封闭型成藏系统以及三叠—侏罗系常压开放型次生油藏成藏系统。塔中成藏系统可分为中央断垒带原生—次生油气藏成藏系统和塔中北斜坡原生油气藏成藏系统,后者又包括奥陶系垂向运移成藏系统与石炭系侧向运移成藏系统。库车前陆油气系统可划分为北单斜带近源常压开放型成藏系统、中部前陆逆冲带近源—自源超压—常压封闭—开放型成藏系统以及轮台凸起近源—远源常压开放型成藏系统3个成藏系统。

STUDY ON THE RESERVOIR-FORMING SYSTEMS OF THE TARIM BASIN

The reservoir forming system (or named the hydrocarbon migration accumulation system) is defined as a relatively independent system of hydrocarbon migration and accumulation within a petroleum system. The reservoir for ming system is also a natural unit of petroleum exploration and assessment, and its place in a petroliferous basin is just between a petroleum system and a play. The Tarim is a basin with multiple reservoir forming systems within a petroleum system. In the Manjiaer petroleum system of the craton area, there exists at least three large reservoir forming systems, i.e., the North Tarim, Central Tarim and West Manjiaer systems. And the North Tarim can be further divided into Lunnan and some other reservoir forming systems. The Lunnan reservoir forming system is actually composed of three subsystems, namely, the Ordovicion primary and se condary reservoir forming subsystem, the Carboniferous overpressure semi closed reservoir forming subsystem and the Triassic Jurassic secondary reservoir forming subsystem where most oilfields are the results of oil re migration from the Ordovician and Carboniferous reservoirs along the newly formed normal faults nearby driven by gas intrusion. The Central Tarim includes two reservoir forming systems named the Central Faulted Belt primary and secondary reservoir forming system and the North Slope primary reservoir forming system, and the latter can be subdivided into the Ordovicion and Carboniferous hydrocarbon migration accumulation subsystems, in each of which vertical and lateral migration and accumulation is predominated respectively. In the Kuche foreland petroleum system, three reservoir forming systems are distinguished, i.e., the North Kuche Slope normal pressure open system, the Central Thrust Belt normal and over pressure open closed system, and the Luntai normal pressure open reservoir forming system. And the Central Thrust Belt system can be subdivided into the above Tertiary seal and the under Tertiary seal two subsystems. In the above Tertiary seal subsystem, se condary oil reservoirs are mainly formed; whereas, the under Tertiary seal subsystem is the character of over pressure gas accumulation.