藏北羌塘盆地上三叠统肖茶卡组沉积相与含油性

羌塘盆地是发育在青藏高原北部的一个中生代海相沉积盆地,面积达16×104km².晚三叠世时期,羌塘盆地总体呈现出一隆两坳的古地理格局,并发育了一套陆源碎屑和碳酸盐岩混积型沉积.该区沉积类型多样,主要发育有三角洲、滨岸、碳酸盐台地、深水沉积等4种沉积体系.在此基础上,分析了该区油气地质条件.认为研究区北部坳陷带成油物质基础较好,中央隆起带两侧的三角洲砂体是油气运移的主要指向.

SEDIMENTARY FACIES AND HYDROCARBON OCCURRENCE OF UPPER TRIASSIC XIAOCHAKA FORMATION IN QIANGTANG BASIN

Qiangtang Basin is Mesozoic marine sedimentary basin located on Qingzhang Plateau,with one hundred and sixty thousand square kilometers.The lithofacies paleogeographic environment of Upper Triassic is characterized by one uplift and two depression:the North Qiangtang Depression、the Central Uplift and the South Qiangtang Depression,and developed a set of mixed carbonate-terrigenous clastic sediments.There are four mainly kinds of depositional systems in the Xiaochaka Formation,such as delta depositional system、littoral depositional system、carbonate platform depositional system、deep-water depositional system.Among of them,the carbonate platform system is most widely distributed in the area.The laws of hydrocarbon distribution and the major reservoir sandbodies of Upper Triassic are concluded that the North Qiangtang Depression poesses good hydrocarbon generating condition,and delta sandbodies in both side of the central uplift is the direction of hydrocarbon Migration.In the meantime,this paper pointed out the direction of future oil and gas exploration in Qiangtang Basin.