10.4122/1.1000000474
Van Dijke, Rink
Rink
Van Dijke
rink@pet.hw.ac.uk
Piri, Mohammad
Mohammad
Piri
mpiri@princeton.edu
Sorbie, Ken
Ken
Sorbie
ken.sorbie@pet.hw.ac.uk
Blunt, Martin
Martin
Blunt
m.blunt@imperial.ac.uk
Van Dijke, Rink
Rink
Van Dijke
rink@pet.hw.ac.uk
Criterion for three-fluid configurations including layers in pores with non-uniform wettability
XVI International Conference on Computational Methods in Water Resources
2006
2006
Recently, a considerable effort has been made to determine the precise criteria for
three-fluid configurations in pores of angular cross-sections, based on capillary
entry pressures (van Dijke et al., J. Colloid Interface Sci. (2004) 184; van Dijke
and Sorbie, Proc. CMWR XV, Chapel Hill (2004); Piri and Blunt, Phys. Rev. E, 70
(2004) 061603; Helland and Skjaeveland, Proc. 8th Int. Symposium on Reservoir
Wettability, Houston (2004)). It has been shown that implementation of these
criteria in pore network models may have a large effect on the simulation of three-
phase displacements processes, such as NAPL migration in the unsaturated zone and
gas injection for improved oil recovery. These configurations may contain thick
conducting fluid layers, such as oil layers residing between gas in the centre and
water in the corners of the pore, which significantly affect oil relative
permeability. For pores of uniform, but arbitrary, wettability and in the absence
of contact angle hysteresis a precise, thermodynamic, criterion for the existence
of such layers has been established before. In this paper, we derive a similar
criterion for pores of non-uniform wettability, a condition that commonly occurs
when only parts of the pore walls are exposed to oil. Moreover, we show how this
criterion depends on the different processes by which these layers form or
collapse, such as gas invasion or oil extraction, as in each process different
values of the various contact angles (advancing, receding or stationary) are
involved. This criterion for formation and collapse of layers is consistent with
the capillary entry conditions for the accompanying three-phase bulk phase
displacements, which is essential for the accurate pore-scale modelling of three-
phase flow.