鄂尔多斯盆地延长组长6油层组储集层是受沉积作用和成岩作用共同控制的典型低孔低渗储集层.长6油层组储集层主要为长石砂岩、岩屑长石砂岩和长石岩屑砂岩.盆地北部砂体具有长石含量高和石英含量低的特点,西南地区具有长石含量低、石英含量高和杂基含量高的特点.储集空间以剩余粒间孔和次生溶蚀孔为主.主要成岩作用类型有压实作用、胶结作用以及溶蚀作用,其中绿泥石胶结和长石、浊沸石溶蚀是有利的成岩作用,压实作用和碳酸盐胶结作用是使原生孔隙减小和储集层致密的重要因素.成岩相平面分布有安塞地区与华池地区两种不同的模式.影响成岩作用的因素有物源成分、沉积环境、构造活动、生烃作用以及大气水淋滤作用等,其中沉积环境控制了砂体的分布,并进一步影响到储集层成岩作用类型及物性特征.%The reservoir of the Chang 6 interval of Upper Triassic Yanchang Formation in the Ordos Basin, controlled by deposition and diagenesis, is characterized by low porosity and extraordinary low permeability. Its rock types mainly include feldspathic sandstone, lithic arkose and feldspathic litharenite. The sandbodies are rich in feldspar and low in quartz in the southern basin, but low in feldspar and rich in quartz and argillaceous matrix in the southwestern basin. The reservoir spaces are mainly residual interg-ranular pore and dissolution pore. The diagenetic types controlling the reservoir include compaction, cementation and dissolution, in which the chlorite cementation, feldspar dissolution and laumontite dissolu- tion are favorable to form high quality reservoirs, while the compaction and carbonate cementation are the main contributors to decreasing the intergranular pore and reservoir compaction. There are two kinds of di-agenetic facies models which are the Ansai and Huachi. The controlling factors on diagenesis are provenance , sedimentary environment, tectonic activity, hydrocarbon generation, meteoric water etc,, and the sedimentary environment controlled the sandbody development firstly, then influence the type of diagenesis and physical property of the reservoir.
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