STEAM AND MICRO/NANOEMULSION SYSTEMS INJECTION AS AN ENHANCED HEAVY OIL RECOVERY METHOD
Enhanced Oil Recovery, Microemulsion, Nanoemulsion, Steam, Heavy Oi
Oil production in onshore fields in Northeast Brazil is in sharp decline, requiring the application of advanced recovery methods to reverse this tendency. For these fields, steam injection is widely used, however, in advanced stages of injection, it can have a high cost and low efficiency. In this case, the use of chemical methods associated with steam can lead to an increase in oil recovery. In this study, micro (MS) and nanoemulsion (NS) systems, consisting of Ultranex NP 100 (surfactant), n-butanol (cosurfactant), synthetic produced water (aqueous phase), and kerosene (oil phase ), were injected associated with steam as a heavy oil recovery method for siliciclastic reservoirs. The systems were characterized in terms of droplet diameter, surface and interfacial tension, rheological behavior and viscosity, besides the effect on the wettability of the sandstone rocks used, Berea sandstone and sandstone from the Brazilian Northeast. In the coreflooding tests, the parameters of surfactant concentration, injection order of the steam and solution banks, injection method (co-injection or alternating injection), injection flow rate and volumetric proportion of the injected fluids were evaluated. All developed solutions showed a reduction in surface and interfacial tension and changed the wettability of the sandstones to water-wet, favorable characteristics for use as an advanced recovery method. The use of a microemulsion solution with 8.66% surfactant in its composition co-injected with steam in the same proportion at a flow rate of 0.125 mL/min showed the best result for oil recovery factor (70.10%) in the Berea sandstone and in the reservoir sandstone (54.34%). The results of this study validated the proposed technique of using an advanced hybrid recovery method (thermal method associated with the chemical) for heavy oil, which can boost the revitalization of mature fields, ensuring the extension of production and the stimulation of regional development.