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根据岩心观察描述、铸体薄片、扫描电镜、岩心分析化验等资料,对柴达木盆地油泉子油田油砂山组储层特征及低渗透成因进行的研究结果表明,储层物性总体较差,储集空间以剩余原生粒间孔隙和溶蚀孔隙组合为主,孔隙结构类型属小孔-微细喉道型。沉积因素对低渗透储层的形成起决定性作用,储层粒度细,碳酸盐和泥质含量高,原生孔隙不发育,储层极易被压实,地下酸性流体难以进入,影响了溶蚀作用的进程。成岩作用是储层低渗透成因的最主要的影响因素,压实和胶结作用使原生孔隙空间不断缩小,储层孔隙渗透性降低,岩石致密。溶蚀作用和微裂缝发育不充分,对储层没有明显的改造作用,也是低渗透储层形成的一个重要原因。
According to the description of core observation, thin cast film, scanning electron microscopy, core analysis and other data, the study on the reservoir characteristics and the causes of low permeability in the oil sand area of the Oil Spring Oilfield in the Qaidam Basin shows that the reservoir properties are generally poor, Set space to residual primary intergranular pores and dissolved pore combination, the pore structure type is a small hole - fine throat type. Sedimentary factors play a decisive role in the formation of low-permeability reservoirs. The reservoirs have fine grain size, high carbonate and shale content, low primary porosity, easily compacted reservoirs and difficult access of subterranean acid fluids, affecting the dissolution The process. Diagenesis is the most important factor that causes the low permeability of reservoirs. Compaction and cementation keep the original pore space shrinking, the porosity of reservoir decreases and the rock is dense. The dissolution and microcracks are underdeveloped and have no significant alteration effect on the reservoir, which is also an important reason for the formation of low-permeability reservoirs.