Combining Nanocatalyts with Solvent as a Strategy to Improve Steam-Based Hybrid Technology: Phase Behaviour Modelling and Thermal Simulation Approach

Abstract

Abstract As a strategy to optimize the recovery and energy efficiency in cyclic steam stimulation (CSS) processes, the alternative of combining steam - nanosolvents has been under study in Colombian heavy oil reservoirs. The use of oil-based nanocatalysts (nanosolvents) in combination with steam allows extending the effectiveness of the catalyst, transporting it better within the reservoir due to the solubility of naphtha in the crude oil. The interaction phenomena associate with this hybrid technology must be evaluated under a robust phase behavior study which represent oil - solvent interaction analysis and, the effect on the oil density and oil viscosity at different temperatures. This work shows a methodology to incorporate solvent/oil mixtures phase behavior into the field numerical model. Based on experimental PVT tests (such as compositional analysis and fluids characterization) a fluid model was developed. Using Peng Robinson Modified Equation experimental data were adjusted such as GOR and density. Additionally, the mixture viscosity were fitted with the modified Pedersen equation. Incorporate the effect of nanocatalysts in the numerical modeling required the grouping by pseudo-components of live oil according to the proposed kinetic model, obtaining a good adjustment and a better representation of the live oil. This allowed the inclusion of the component's properties such as asphaltenes and upgrading oil used in the kinetic model of the CSS + solvent enhanced with nanoparticles technology. The experimental results indicate the high solubility of the solvent in crude oil, due that a linear mixture rules for naphtha - oil was developed. Additionally, a representative fluid model is mandatory to represent aquathermolysis catalytic reaction in the CSS. The modelling results show that the highest incremental recovery of the nanofluid was achieved in early stages of CSS with an increase of 23% concerning the baseline. Likewise, a sensitivity analysis was developed based on a fixed cumulative oil production in the presence of nanofluids, obtaining a 61% reduction in the steam injection rate, indicating that the hybrid technology not only generates positive impacts on recovery but also positively impacts on improving energy efficiency and reducing the carbon footprint. A novel methodology to represent the fluid interaction in presence of nanocatalysts in the numerical modeling was developed as a strategy to incorporate oil compositional changes in thermal hybrid process.