Abstract:

According to the characteristics of nonDarcy flow and threshold pressure gradient in low permeability reservoirs，the deliverability prediction general formula for multilateral well pattern and the analytical model which is inverted fourspots pattern，inverted fivespots pattern，inverted sevenspots pattern and inverted ninespots pattern are established through water and electricity similarity principle and equivalent flow friction method.The data of field verification and numerical simulation experiment indicate that the forecasting precision of the models is very good.The effects of well pattern number and effective thickness and threshold pressure gradient are analyzed with the model.The result indicates that when threshold pressure gradient is increased，different well pattern productivity ratio of multilateral wells is decreased.With the increasing of L/d，productivity ratio of multibranched well is increased；when L/d is the same，with the increasing of well pattern number，productivity ratio of multilateral well is increased；with the increasing of effective thickness，productivity ratio of multilateral well is decreased.

Key words: low permeability, multi lateral well, deliverability forecast, well pattern, analytical model