Surfactant Formulation for Foam Mobility Control and Gas Shut-Off in Harsh Operational and Reservoir Conditions

Abstract

Surfactants in literature have been reviewed and evaluated as foaming agents, but few of them fit our harsh operational and reservoir conditions. Therefore, surfactant formulations were tuned with guide of micelle electrostatic model and Winsor type phase behavior. The novel formulations are compatible with high temperature (94 ℃) and wide salinity (50 - 290 g/L). Moreover, one of the formulations can generate relatively weak foam at high residual oil saturation (Sor), but strong foam at low Sor. This auto-selection of foam by Sor allows to block the swept and clean zone, but not lockdown the virgin oil reserve and flooding front. At the end of foam flooding, almost 100% residual oil was recovered. Additionally, the operational conditions, such as injecting brines, anti-corrosions, demulsifiers, etc., are often subjected to be changed. Therefore, a rapid bulk-foam test is proposed to re-verify the compatibility of the formulation with the new operational condition.