Steady-State Multi-Phase Relative Permeability Under Simultaneous Water and Gas Injection: Application on Different Rock Types

Abstract

Quantification of multi-phase flow processes taking place in natural porous and fractured rocks has a remarkable relevance to economically sustainable management and viable development of oil- and gas-bearing geologic formations. Simultaneous flow of two- and three- fluid phases in porous media is typically based on a continuum scale description which imbues relative permeabilities as key system parameters to be estimated and linked to fluid saturations. Estimates of relative permeabilities are then employed to support better the quantification of productivity, injectivity, and ultimate recovery from reservoirs. In this work, we report the results of laboratory-scale three-phase relative permeabilities on diverse core samples. We also investigate the saturation history dependency (i.e. hysteresis) of three-phase relative permeability during under simultaneous water and gas injection. Three-phase relative permeability data are obtained at different condition by the way of a Steady-State (SS) technique. We use direct X-Ray technique to assess the spatial and temporal dynamics of in-situ saturations. Dual X-Ray energies are employed to assess the SS three-phase saturations. The use of in-situ X-Ray scanning technology enables us to accurately measure fluid displacement during the core-flooding test. The SS three-phase experiments are condcuted by following various saturation paths including CDI, DDI and IDI. The C, D and I letters represent as Constant, Increasing and Decreasing (i.e., CDI saturation variation abbreviates Constant water, Decreasing oil and Increasing Gas). We observe in all the of the tests, water relative permeabilities display an approximately linear dependence on the logarithm of its own saturation and show no dependency upon saturation history. Three-phase oil relative permeability appears to be varied with all saturations and be dependent on all saturations phases. Gas three-phase relative permeability was affected more by saturation history than other phases. However in the test where the gas fractional flow was increased, the dependency of gas relative permeability on gas saturation was observed. As only a limited quantity of complete three-phase data are available, this study stands as a reliable reference for further model development and testing.