The Optimization of Well Pattern in Ultralow-Permeability Reservoir

Abstract The reasonable well pattern arrangement is a key factor that ultra-low permeability oilfield are developed successfully because it is usually relative to fracture. By using numerical modeling, driving replacement etc reservoir engineering methods after reviewing the evolution of well pattern for Changqing ultra-low permeability reservoir, the paper presents rhombus inverted nine-spot and rectangle well pattern matching best the fracture and injection-production pressure system. In the development practice, we adopt square inverted nine-spot, rhombus inverted nine-spot, rectangle well pattern according to little, relative, good of fracture growth, and have achieved better development effects. Introduction It is well known that ultra-low permeability reservoir has some features such as low permeability, natural fracture and low pressure as well as low natural productivity. Fracturing is often used to get industrial oil stream, water injection is to lengthen stable production period and enhance ultimate recovery efficiency. So the key for development well pattern arrangement is to enhance individual-well production sweep efficiency and ultimate recovery efficiency. The paper presents rhombus inverted nine-spot pattern and rectangle pattern on the base of optimum matching of fracture system, displacement pressure system and pattern system. In development practice of oilfield, square inverted nine-spot, rhombus inverted nine-spot and rectangular pattern are adopted according to little, relative, good of fracture growth. This has made great progress in Ansai, Jingan and Xifeng oilfield, which is regarded as a guide to develop the same kind of oilfield.