柴达木盆地乌南油田N12、N22碎屑岩储层特征及其影响因素分析

利用岩石和铸体薄片、扫描电镜、元素分析、压汞等分析测试手段，特针对N12和N22碎屑岩储层特征、成岩作用以及影响因素，对30余口井的样品和资料进行了分析研究。结果表明，乌南油田N12和N22砂岩储层岩石类型为长石岩屑砂岩和岩屑长石砂岩；经历的主要成岩作用类型有粘土膜（粘土环边）的形成、机械压实作用、胶结作用、交代作用和溶解作用。砂岩储层孔隙类型主要是次生孔隙和原生粒间孔隙，其中次生粒间溶孔占绝对优势，其次是基质内微孔隙和裂缝孔隙。孔隙度多为8%～18%，渗透率多为0.5×10-3～10×10-3 μm2，属中低孔低渗储层。影响研究区储层物性的主要因素有沉积相带、成岩作用和孔隙结构，其中最有利的储集砂体微相为分流河道和河口坝（细砂岩和粉砂岩相），其次为远砂坝粉砂岩相，间湾薄层砂岩储集性能差。胶结作用和溶蚀作用是影响乌南油田N12和N22储层的最主要的成岩作用。

Detrital Reservoir Characteristics and Its Controlling Factors in Clastic Reservoir N12 and N22 of Wunan Oilfield , Qaidam Basin

Wunan Oilfield is one of the most important oil and gas fields in Qaidam basin. Its exploration since the beginning of 1957. The Nancan 2 Well found industrial oil flow after the oil test in 1979. In recent years, in the Lv 6 Well, Lv 2 Well, Wu 3 Well and Wu 4 Well and many much wells were found industrial oil flow in the stratum of N12 and N22. This article aims at clastic reservoir characteristics, diagenesis and the factors influencing on the stratum of N12 and N22. Through analyse the data of at least 30 wells, use the sections, scanning electron microscope , element analysis, mercury porosimetry and many other means studies, the result shows that the sandstone reservoir rock type are feldspar debris sandstone and debris feldspar sandstone in stratum of N12 and N22 Wunan Oilfield. The main diagenesis types include of clay film (Clay Central)，the machine made compaction, cementation，displacement and dissolution. Thereinto cementation and dissolution is the most important diagenesis in the stratum of N12 and N22 in Wunan Oilfield. Porosity mainly distributed in 8% to 18%, the permeability are mainly distributed in the 0.5×10 3μm2 10×10 3μm2, as the low porosity and permeability reservoir. The main effect factors of reservoir porosity and permeability include sedimentary facies, diagenesis and structure of reservoir, thereinto, the favorable sedimentary facies are distributary channel and estuary (sandstone and siltite facies), secondly, siltstone facies of distal bar, at last, the reservoir quality of thin sand of the bay is poor.