Source Distributed Fracture Model for the Numerical Modelling of Oil Sands Steam Stimulation

Abstract

This paper describes a source distributed dynamic fracture model. The model, coupled with the thermal simulator ISCOM, was used to investigate oil sand reservoir performance during steam stimulation.The source distributed fracture model developed is based on the following assumptions: The fracture can propagate through a given path of adjacent reservoir blocks, creating a fracture channel within a reservoir. The number of fracture channels and reservoir geometry are not restricted. The position of a fracture or microfracture system inside a given reservoir block is not defined -the fracture is represented as an effective source of fluid and heat transferred to the block. Fracture volume is disregarded. The mass and heat balances are solved exactly for each fracture channel. Fractures can be operational only during the injection period. Fracture opening and closure are governed by calculated values of opening, propagation and closure pressures. Effective absolute permeability ~nd conductivity inside a drainage area are treated as adjustable parameters.Results of this investigation show that reservoir performance is strongly affected by the variation of effective fracture parameters, References and illustrations at end of paDer. 249 especially changes in effective fracture conductivity in the vicinity of a wellbore and the mobile and connate water saturations.