Oil-Water Two Phase Flow Model Considering Threshold Pressure Gradient

Base on the non-Darcy flow problem in low permeability reservoirs, the oil-water two phase radial fluid flow model considering threshold pressure gradient is established, the output and formation pressure distribution formulas are obtained，the production variation rule and the influence threshold pressure gradient on formation pressure distribution of different permeability and different well spacing are discussed, the reasonable well spacing of different threshold pressure gradient is calculated. Research shows that, the smaller the permeability, the bigger the corresponding threshold pressure gradient, the faster the production shortfall; in the same permeability, the greater the well spacing, the less the output; the fluid flow requires energy expenditure to overcome threshold pressure gradient, the smaller the permeability, the greater the resistance, the faster the formation pressure descent near wellbore. The reasonable well spacing for effective production is obtained by output formula, which provides the scientific foundation for improving the development effects.