松辽盆地北部泉三、四段储层物性影响因素分析

Controls of reservoir physical properties of the Quan 3 and Quan 4 members in northern Songliao Basin

发育于泉头组三、四段的扶余油层和杨大城子油层是松辽盆地的主力油层之一,该油层低孔特低渗的物性特征制约了扶杨油层的勘探开发。为了研究松辽盆地北部泉三、四段储层物性的影响因素和低渗透储层的成因,本文以12 062组实测孔隙度和渗透率数据为基础,讨论了泉三、四段的物性影响因素。结果表明,总体上影响泉三、四段储层物性的主要因素是成岩作用,其次是沉积作用。泉三、四段储层成分成熟度低、粒度细、泥质含量高、成岩作用强是渗透率低的根本原因。但在不同成岩阶段,沉积相和成岩作用对储层物性的影响不同,在早成岩阶段储层物性主要受沉积相的影响,在中成岩阶段A,亚期以后储层物性主要受成岩作用影响,在中成岩阶段A_1亚期储层物性受二者的影响程度相近。处于不同成岩阶段、发育于不同沉积相的砂体,可形成各种类型的储层。

Fuyu oil layer and Yangdachengzi oil layer,developed in the third and fourth members of Quantou Formation,are two of the major reservoirs of Songliao Basin.However,their lowporosity and extra lowpermeability restrict the exploration and exploitation of the basin.To study the controls of reservoir physical properties and the causes of low permeability reservoirs of the third and fourth members of Quantou Formation in northern Songliao Basin,the influence factors were studied by using 12 062 data of the measured core porosity and permeability.As the results show,the dominant influence factors on reservoir physical properties are diagenesis,following by sedimentary facies.The fundamental causes of lowpermeability are its low compositional maturity,fine particlesize,mini pore throat,high clay matrix content,and strong diagenesis.Nevertheless,the effects of sedimentary facies and diagenesis on reservoir physical properties vary in different diagenetic stages.Particularly,sedimentary facies is the dominant factor in early diagenesis,while diagenesis is a main factor after subperiod A2 of middle diagenetic stage,these two factors influence weighs the same in subperiod A1 of middle diagenetic stage.The sand bodies which development in different sedimentary facies and different diagenesis stages can form different types of reservoirs.