Proceedings of the Second International Energy 2030 Conference,
November 4-5, 2008, Abu Dhabi, UAE

Investigation of the Mobilization of Residual Oil Using Micromodels

A. S. Ibrahim
The Petroleum Institute, UAE

N. S. Abdelfattah
The Petroleum Institute, UAE

I. Chatzis
The Petroleum Institute, UAE

Abstract
The mobilization of residual oil was investigated in glass micromodels consisting of capillary networks with water-wet wettability as a function of capillary number (ratio of viscous to capillary forces). The micromodels used in this work had variable pore throat and pore body size distribution. Experimental results demonstrated that the entrapped residual oil blobs have a preferable orientation along the macroscopic flow direction of waterflooding. For substantial mobilization of the waterflood residual oil, the corresponding capillary number needs to be 100 times larger than that for the onset of mobilization of the largest blobs in place at the end of waterflooding. The reduced residual oil saturation with increasing capillary number obtained in this study is in qualitative and quantitative agreement with published capillary number curves for water-wet sandstones. A key feature of oil blob mobilization at high capillary number is the break-up of mobilized blobs to sub-pore size droplets as they flow through the pore network, some of which attach to the pore walls and thus making complete mobilization very difficult. It was concluded that glass micromodels offer the potential to screen the best surfactant formulations for EOR application using residual oil mobilization experiments and for displacements of continuous oil in place.