准噶尔盆地乌尔禾地区风城组云质致密油储层特征

摘要

The Permian Fengcheng Formation reservoir in the Urho area of Junggar Basin is a typical tight oil reservoir.Based on the core description,thin section identification,comprehensive data of sedimentology and physical property,this paper discusses the reservoir characteristics and controlling factors of the Fengcheng Formation in detail.It determines that dolomitized rocks are the main rock types of the reservoir.The reservoir development is multiply controlled by sedimentary facies,diagenesis,tectonism and overpressure.The reservoir type is controlled by two small blocks with different tectonic settings in the fault zone and the slope area.The fracture reservoir and pore-fracture reservoir are mainly developed in the fault zone,and the fracture-pore reservoir is mainly developed in the slope area.The semi-deep to deep lacustrine facies is the background condition,the argillaceous dolomite and dolomitized mudstone are the material foundation,the fracturing and dissolution is necessary to improve the reservoir quality and generate superior reservoir,and the overpressure is usually the "sweet spot" in a tight oil reservoir.%准噶尔盆地乌尔禾地区二叠系风城组油藏产层具有典型的致密油储层性质.在岩心观察描述和薄片鉴定基础上,结合沉积学和物性分析等资料,探讨了风城组致密油储层特征和储层发育控制因素,确定云化岩类是储层的主要岩石类型.储层发育同时受沉积相、成岩作用、构造和异常高压复合控制,储层类型受断裂带和斜坡区2个不同构造背景性质的小区块控制.其中断裂带主要发育裂缝型和孔隙-裂缝型储层,斜坡区以裂缝-孔隙型储层为主.半深湖—深湖相沉积环境是储层发育的背景条件,云泥岩、泥云岩是储层发育的物质基础,经历破裂和溶蚀作用是提高储层级别和形成好储层的必要过程,而异常高压区往往是致密油储层中“甜点”的产出位置.