等效裂缝密度在锦州南变质岩潜山裂缝定量表征中的应用

裂缝发育密度是裂缝性储层裂缝特征研究与定量表征的重要参数之一.锦州南太古宇变质岩潜山裂缝异常发育,岩心分析裂缝密度很高,而成像测井计算的裂缝密度却非常低.研究发现,该潜山多数井裂缝异常发育段由于裂缝过于发育造成岩石破碎,从而使成像测井仅能识别出少数裂缝,造成成像测井计算的裂缝密度偏低.为了准确描述该变质岩潜山储层裂缝的发育情况,首次将成像测井直接解释的裂缝密度与储层总孔隙度和电阻率建立关系,提出等效裂缝密度的概念,并将该等效裂缝密度用于裂缝三维定量表征.油藏动态响应表明,基于等效裂缝密度的裂缝分布三维模型可较准确地描述裂缝的发育情况,从而有效地指导油田的开发与生产.

Application of Equivalent Fracture Density in the Process of Quantitative Characterization of Fractures in Jinzhounan Metamorphic Buried-hill

Fracture density is one of the main parameters which are important to fracture characteristics and quanti- tative characterization of fractured reservoir. Jinzhounan Arehaean metamorphic buried -hill develops a large num- ber of fractures. Fracture density of core analysis is very high, but according to image logging calculating, fracture density is very low. The study finds that fractures of most wells in the buried - hill over - develop in some intervals and result in breaking of the rock, so that the image logging can only identify a small number of cracks and result in fracture density which is calculated according to image logging is low. In order to accurately describe the develop- ment of fractures in buried - hill reservoir, for the first time, this paper establishes relationships between image log- ging fracture density and reservoir total porosity or reservoir resistivity, proposes the concept of equivalent fracture density and uses it to quantitatively characterize fractures. Petroleum reservoir performance shows that fracture dis- tribution 3 D model based on the equivalent fracture density can more accurately describe pattern of fracture occur- rence and is able effectively to guide the development and production of the oilfield.