陆相盆地露头储层地质建模研究与概念体系

GEOLOGIC MODELING FOR OUTCROP RESERVOIR OF CONTINENTAL BASIN AND THE CONCEPTUAL SYSTEMS

露头储层地质建模的关键是阐明储层非均质性特征（即储层沉积非均质性、储层成岩非均质性和储层物性非均质性特征）。储层非均质性具有层次性，并可以分为３种尺度（大尺度、中尺度和小尺度）进行研究。在不同尺度的沉积非均质性研究基础上，建立储层内部构成格架模型是储层沉积非均质性研究所要解决的主要问题，因此补充和完善砂体内部构成单位和等级界面分析法的概念等级序列尤为重要。本文提出河道单元在各类河道中具有普遍存在的规律，并指出不同类型河道砂体的内部构成复杂性和层次性具有差异，认为形成这种差异的主原因在于古流能量存在差异和沉积作用方式的不同。建立高渗透网络格架模型的基础是识别和划分流体流动单元。流体流动单元是以隔挡层为边界按水动力条件划分的建造块，其规模和分布空间与砂体内部构成单位关系密切。不同尺度的储层物性非均质性具有不同的研究对象和重点。以中尺度研究为例，储层物性非均质性的焦点在于流体流动单元的差别上以及构成流体流动单元的储层岩性相的差别上。沉积作用对储层物性的影响无疑是重要的，但如果叠加有不均匀的成岩作用的影响，那么整体孔渗值将会大大地降低。

Abstract The geologic modeling for outcrop reservoirs depends on the clarification of the characteristic heterogeneity of reservoirs,including the depositional heterogeneity,diagenetic heterogeneity,and the heterogeneity of porosity and permeability.The heterogeneity of resevoirs can be studied on three scales (macroscopic scale,mesoscopic scale and microscopic scale). From the study of depositional heterogeneity on different scales,the essential procedure is to model the internal architectural frame,for which it is significant to complement and improve the conceptual order for the internal architectural units and bounding surfaces.This paper indicates the common channel units in various channels,explains the differences of the internal architetural complexity and beddings for different channel sand bodies,and takes the different palaeocurrent energy and depositional modes as the major causes for the differences. Modeling the strong permeation net frame is based on recognition and differentiation of fluid flow units which are building blocks differentiated with isolate barrier beds as the bounding hydrodynamic conditions and are closely related with the internal architectural units of sand bodies in scales and spatial distribution. The study on the heterogeneity of reservoir porosity and permeability of different scales depends on different subjects,for instance,the study for mesoscopic scale is focused on the differences between fluid flow units and the differences between the reservoir lithological facies which formed the architectural units. Deposition significantly dominates the porosity and permeability of reservoirs,but in case of heterogeneous diagenesis in superposition,the integral porosity and permeability will greatly decrease.