柴达木盆地茫崖坳陷含油气系统及勘探方向

PETROLEUM SYSTEMS AND EXPLORATDN D IRECTDN OF THE MANGYA DEPRESSDN IN THE QA DAM BASIN

范连顺 王明儒

Fan Lianshun Wang Mingru

青海石油管理局, 敦煌市 736202

Qing hai Bureau of Petroleum Admin istration, Dunhuang 736202

柴达木盆地西部茫崖坳陷是该盆地第三系主要产油气区.分布着当今世界上海拔最高的油气田.是一个由中生代弧后准前陆盆地向新生代山间盆地发展演化的一个大型坳陷.充填了内陆湖泊半干旱气候下咸化环境-半咸化环境的大套泥质岩,含钙质泥岩及碳酸盐岩和碎屑岩.形成一套巨厚的具两期排烃高峰的烃源岩,两种类型的储集岩系、特殊的盖层条件及运移条件.各成油要素在时空上不同配置关系构成茫崖坳陷至少由5个二级含油气系统组成的一个一级大型含油气系统.各二级含油气系统在空间上多重重叠、相互交叉,在时期上连续接替、逐层发展.通过对该区含油气系统的分析,提出下一步勘探方向应以深层目标为主,主攻三带一坡及岩性地层类油气藏.

The Mangya Depression in the western part of the Qaidam Basin is the major Tertiary hydrocarbon-producing area of the basin. There distributes the highest gas and oil fields above sea level in the world It is a megadepression evolving from a Mesozoic back-arc paraforeland basin to a Cenozoic intermountain basin, and filledwith large sets of argillaceous rock,calcareousmudstone,carbonate rock and clastic rock of saliniferous-semisaliniferousenvironmentunder the semidry clinateof inland lakeswhich foam a set of giant-thick hydrocarbon source rock w ith two periods of hydrocarbon expulsion peaks, two types of reservoir series aswell as special capping and migration conditions The different allocation of variousoil-generating elements in tine and space constructs the Mangya Depression a large scale of first-order petroleum system constituted by at least five secondrorder petroleum system s Each second-rder petroleum system show smultip1e superposition and intersection in space, and connects continuously and develops layer by layer in tine,By analyzing on thepetroleum system sof the area, it is suggested that the exploration direction of the next step should be mainly deep targets, especially the three zones, the one slope and lithos-tratigraphic gas and oilpools

https://doi.org/10.11781/sysydz199901041