A new prediction model of horizontal well productivity for heavy oil reservoir

Laboratory experiments of heavy oil with different viscosities have proved that there exists threshold pressure gradient in heavy oil flow,which increases with oil viscosity.A new mathematical model of horizontal well productivity prediction is established for heavy oil reservoir by using the principle of velocity potential with consideration of three-dimensional seepage flow and threshold pressure gradient.The new model has been applied to prediction of horizontal well productivity in offshore heavy oil reservoir and analysis of the effect of threshold pressure gradient on horizontal well production and producing range.It shows that the higher the threshold pressure,the lower the horizontal well productivity;threshold pressure gradient has led to the increasing of seepage resistance and the decreasing of producing range of reserves.