关键词: 特低渗透油藏, 储层结构, 显裂缝系统, 岩块系统, 微缝特征, 开发效果

Abstract: This paper described lowest fracture reservoir structure, especially the microfractures in rock mass starting from study of characteristics of reservoir, it has very important significance for enhancing the result of developing the lowest permeability reservoir. There are four microfracture groups in the microfracture system, with a length of more than 2 cm and percolation ability of 1100 times as large as rock mass system. A rock mass system is consisting of matrix and microfracture. The length of microfracture is less than 2 cm. It has the small scale in the rock mass. There is a big difference in the percolation ability between the microfracture and the matrix with that of former is 83 times as large as the latter. In terms of the microfractures characteristics of the lowest reservoir, it distributed like zone and is in parallel or "wild goose" array with constant direction. Microfracture zones vary as the property of rocks. The microfractures are divided into effective and ineffective ones. The effective microfracture may play an important role in liquid percolation while the ineffective microfracture may not because of filling calcite in them. The paper also described the effects for the development of the lowest permeability reservoir at injecting water mode. The reservoirs with more microfractures would be suitable to linear injection under 210 m of row distance. With the small injecting pressure, a high oil production would be maintained. In conclusion, this study has very important meaning for the evaluation and economic development of lowest permeability reservoir, and creates a new study area.

Key words: lowest permeability reservoir, reservoir structure, macrofracture systems, rock mass, microfracture characteristics, effects of reservoir development