摘要
新疆和田地区晚石炭一早二叠世沉积时期被面积广阔、水体较浅的陆表海所覆盖.根据陆源物质供应的不同, 可以识别出2种不同的陆表海环境,即:碳酸盐岩台地和滨岸-碳酸盐岩台地.通过对分布在和田地区不同位置的5条代表露头剖面和1口钻井中层序界面的识别、地层的追踪对比以及沉积环境的研究分析,可以建立起和田地区上石炭-下二叠统形成于陆表海环境中的层序地层格架,进而探讨格架内实际地层的石油地质特征,分析其中有利储集层、烃源岩的分布规律及其特征.研究认为:海平面变化、构造沉降、碳酸盐岩生长速率以及陆源物质供应等共同控制着陆表海基准面的变化,控制着格架内沉积物的石油地质特征.其中,碳酸盐岩台地环境古地形坡度极缓,基准面上升初期以及下降末期形成的富含粒屑的并进型碳酸盐岩沉积具有良好的储集性能,且其顶部常常暴露水面,有利于储集性能的改善.滨岸-碳酸盐岩台地环境古地形坡度略陡,受到陆源碎屑物质的影响较强,基准面上升期形成的贫粒屑富含有机质的追补型碳酸盐岩沉积,可以形成比较好的烃源岩,也拥有比较好的封盖能力.
The upper Carboniferous and lower Permian of Hetian in the south of Tarim Basin are deposited in the epeiric sea. There are two kinds of depositonal environments. One is the carbonate platform without terrigenous supply. The other is the shore-carbonate platform with terrigenous supply. After identifying the sequence boundaries, studying the depositional environments in 5 typical crops and 1 well in Hetian, we established the sequence framework of the upper Carboniferous and lower Permian which is essential for the study of the reservoir rocks and source rocks. The base-level changes associated with subsidence, eustacy and sediment supply control the geometrical framework of the sequences, the properties of the sediments, and the petroleum geologic features. In the carbonate platform, the carbonate generation can keep up with the sea rise during the time of the slow rise of the base-level and at the the late time of the fall of the base-level. And thus the keep-up clastic carbonate deposited there which is the potential reservoir rock in the studied area. In the shore-carbonate platform, the carbonate generation can not keep up with the sea rise. The catch-up carbonate, that contains less detrital fragments but abundant organic matters, can only deposited during the time of the rapid rise of the base level, which may be the good source rock and caprock in this area.
出处
《新疆地质》
CAS
CSCD
2005年第2期117-122,共6页
Xinjiang Geology
