华庆油田长6超低渗透储层岩石学特征

Petrologic Characteristics of Chang 6 Ultra Low Permeability Reservoirin Huaqing Oilfield

华庆油田长6超低渗透储层砂岩类型可划分为长石砂岩、岩屑长石砂岩、长石岩屑砂岩和岩屑砂岩,具有低成分成熟度和中等结构成熟度特点。在研究区范围内,自东北向西南方向岩石类型从长石砂岩、岩屑长石砂岩过渡为长石岩屑砂岩、岩屑砂岩。岩石学特征与储集空间类型及物性分析的结果表明,长石砂岩和岩屑长石砂岩中云母碎屑含量较低,胶结类型以绿泥石薄膜胶结为主,原生粒间孔和溶蚀孔发育,孔隙度和渗透率高,为优质储层;长石岩屑砂岩和岩屑砂岩的长石含量低,云母碎屑含量高,绿泥石薄膜胶结少,原生粒间孔和溶蚀孔均不发育,孔隙度和渗透率低,为差储层。因此,华庆油田的大规模高效开发应主要集中在研究区的北部和中部地区。

Chang 6 ultra low permeability reservoir sandstone in Huaqing Oilfieldcould be divided into arkose,lithic arkose,feldspathic litharenite and lithic sandstone.The reservoir is characterized by low compositional maturity and low textural maturity.From northeast to southwest of the research area the rock types shift from arkose and lithic arkose into feldspathic litharenite and lithic sandstone.According to the analysis of reservoir pore space and physical property,arkose and lithic arkose that have good physical properties are the favorable reservoirs which are inclined into high felspar content,relatively low mica books and grain-coating chlorite preserving many primary intergranular pores and creating lots of dissolution pores,but feldspathic litharenite and lithic sandstone are bad reservoirs which have many mica books and absence grain-coating chlorite leading to the lack of primary intergranular pore and dissolution pore.As a result,the middle part and the northeast part of Huaqing Oilfield area should be the beneficial development block.