A Model for Direct Estimationof Wetting Phase RelativePermeabilities Using a Multistep Drainage Process.

A new analytical model has been developed for determiningthe wettingphase relative permeabilities in a multiple gas–liquid drainageprocess. The multistep drainage process consists of a series of drainageprocesses with a tiered pressure-difference profile. With this model,the wetting phase relative permeabilities can be readily obtainedthrough regression of the wetting phase recovery history. The assumptionsused in deriving the analytical model are examined by numerical simulations.The agreement between the analytical and the numerical results indicatesthat these assumptions are reasonable and valid. Numerical simulationsand laboratory results demonstrate that this model is effective fordirect estimation of the wetting phase relative permeabilities inthe multistep drainage process. [ABSTRACT FROM AUTHOR]