Surfactant Design for EOR Project and Dynamic Surface Tension for Fluid Analysis
Abstract
Surfactant flooding has been shown to increase EOR potential in hydrocarbon reservoirs. Chemical surfactants have been demonstrated to potentially improve EOR in unconventional reservoirs such as shale. Surfactants of different types such as cationic, anionic and nonionic surfactants have been studied extensively for their potential to alter wettability of reservoir rock and improving Estimated Ultimate Recovery (EUR). Nonionic surfactants have been shown to be especially effective in altering Eagle Ford shale wettability.
A methodology for effectively screening surfactants for EOR projects is introduced for a well in the Eagle Ford basin. Practical and chemical effects are considered while formulating an optimal injection fluid for good field scale performance. In the pre-injection phase, laboratory measurements like contact angle and spontaneous imbibition experiments are performed to evaluate wettability alteration performance. The effects of chemical additives are also investigated to ensure no interference from other surface-active chemicals. In the post-injection phase, the oil and water production rates are monitored daily. Produced water samples are analyzed to measure residual surfactant concentration in the produced water through a unique dynamic surface tension methodology. Performance evaluation of the EOR project indicates increased oil and water production rates with low residual surfactant concentrations returning to the surface.
Dynamic surface tension methodology was utilized to develop a method to measure adsorption density on rock samples and characterize the performance based on the surfactant type. Results show that nonionic surfactants have a higher adsorption density on limestone and shale rock compared to sandstone rock.
A systematic methodology for performing dynamic surface tension measurements and estimating the surfactant concentrations by quantitative analysis is proposed.
Citation
Bagareddy, Aashrit (2021). Surfactant Design for EOR Project and Dynamic Surface Tension for Fluid Analysis. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /196466.