浊积岩低渗透储层成因机制及有效性评价——以东营凹陷胜坨地区沙四上亚段为例

Genetic Mechanism and Effectiveness Evaluation of Low-permeability Turbidite Reservoirs——By Taking the Upper Member of Es_4 in Shengtuo Area of Dongying Sag for Example

在对浊积岩储层的岩相特征、孔隙类型、孔喉结构及成岩相类型分析的基础上,研究了东营凹陷胜坨地区沙四上亚段浊积岩低渗透储层的成因机制、主控因素及储层类型,建立了一套浊积岩低渗透储层综合分类评价方法。研究结果表明,胜坨地区沙四上亚段浊积岩低渗透储层的成因机制可分为压实作用低渗型、胶结作用低渗型、压实-胶结综合作用低渗型及溶解改善物性、压实-胶结综合作用低渗型4类。其中,低渗透储层形成的先决条件是沉积作用,而主导因素是压实、胶结作用。溶解作用在一定程度上可以改善储层的储集性能,但无法从根本上改善低渗透储层的物性。结合储层物性下限及其分布情况,将研究区浊积岩低渗透储层划分为优质储层、中等储层、差等储层及非储层4类。

A set of turbidite low permeability reservoir classification and evaluation methods were established by studying the genetic mechanism,main controlling factors and types of the upper member of Es4 low-permeability turbidite reservoirs of Shengtuo Area in Dongying Sag based on characteristics of lithofacies,pore types,pore structures and types of diagenetic facies.The results indicate that low-permeability reservoirs can be divided into four genetic types,such as compacted low-permeability reservoir,cemented low-permeability reservoir,compacted and cemented low-permeability reservoir and dissolution improved and compacted-cemented low-permeability reservoir.Among them,sedimentation is prerequisite condition of forming the low-permeability reservoir,and the compaction and cementation are the dominant factors,while dissolution can not fundamentally improve the physical properties of low permeability reservoir.In combination with the low limit of physical properties and its distribution,low-permeability turbidite reservoirs can be divided into four major categories,such as high-quality reservoir,middle level reservoir,poor reservoir and non-reservoir.