Foam Flooding of Cores Under North Sea Reservoir Conditions

Abstract

ABSTRACT Laboratory corefloods were run to explore the feasibility of foam to provide mobility and injection profile control in a stratified, heterogeneous North Sea reservoir. The objectives were to identify suitable surfactants, from over 100 commercial surfactants initially screened, which were capable of producing stable foam at North Sea reservoir conditions and, to quantify the influence of several reservoir and injection parameters upon foaming performance. The experimental apparatus essential for the laboratory simulation of foam generation and injection into porous media at reservoir conditions is described. The test results showed that, compared with brine injection alone, three surfactants were each capable of substantially increasing core pressure gradients in synthetic porous media, when injected with nitrogen gas at conditions of 4300 psig (29.6 MPa) and 230°F (110°C). Effective, resilient foams can also be generated within natural sandstone cores at injection velocities of 10 ft/d (3.05 m/d). Based on the surfactants evaluated in this study, the dramatic reduction in foam pressure drop (by up to 80 times) in the presence of the North Sea crude used, effectively precludes the use of foam to restrict water or gas channelling at North Sea pressure and temperature.