Chemical EOR in High Salinity-High Temperature Reservoir - Experimental Coreflooding Tests and Numerical Simulation

Recent developments in chemical EOR technologies make now possible to operate in severe environments, characterized by high-temperature conditions and by high salinity and hardness of reservoir brine. A feasibility study was conducted on a field operated by Eni, in order to design a surfactant injection under these challenging conditions. Laboratory studies and simulations were performed to evaluate the potentiality of the technique to increase the oil recovery. Two surfactant formulations presenting good phase behaviour and conferring low interfacial tension between brine and reservoir oil were tested. The dynamic performance of the chemicals was screened with a series of coreflooding tests, carried out using Berea sandstone. Sea water injection was followed by the chemical flooding, so that the additional recovery factor was evaluated. Surfactant adsorption was then measured to select the most suitable formulation. Moreover, core experiments were history matched through numerical simulation to validate the model and obtain scaling parameters of the chemical process for future forecast previsions of surfactant flood benefits at sector scale.