Assessment of Three Phase Relative Permeability Models for Simulation of Tertiary Water and Gas Injection in Water-wet and Mixed-wet Rocks

Providing reliable estimation of three-phase relative permeability is one of the most important concerns for prediction of recovery factor. However obtaining three-phase relative permeability by means of laboratory experiments is a tedious process; therefore, there is a great tendency toward predicting this property empirically. In most of the commercial softwares, merely few methods for estimation of three-phase relative permeability, such as Stone, SWI and Baker are provided. The drawback is that these models are developed for water-wet systems and high gas/oil IFTs, while reservoir rocks are most likely non water-wet and oil/gas system are usually miscible or near-miscible in which gas/oil IFT are whitin extra-low range. In this paper we try to assess the validity of the recently developed three phase relative permeability for gas-water and water-gas injection scenarios. The study covers both water-wet and mixed-wet systems under extra-low gas/oil IFT condition. Required two-phase relative permeabilities as well as three-phase experimental data are obtained from previously published data. A Matlab code is developed and coupled with Eclipse to assess the performance of other three-phase models. Evaluation of recently developed empirical models elucidated that these methods may have more decent predictions. For mixed-wet core in gas-water and water-gas injection processes Corey and Land have the best predictions among different methods. In water-gas injection process for water-wet core, Land and Aziz equations provide the best predictions.

Keywords:

Three-phase Relative Permeability , Tertiary Gas and Water Injection , Mixed-wet