Utilization of Microfluidics Technology for an Efficient Polymer Screening Process in Enhanced Oil Recovery (EOR) Applications

Abstract

This work introduces an efficient approach in addition to the traditional scheme of polymer screening for the application of enhanced oil recovery. Microfluidics technology which requires less sample volumes, and less time consumption, is applied to the polymer screening procedure. This approach delivers an efficient screening process and enables the upscaling of polymer flow behavior in porous media. This work investigates three commercial polymer products, A, B, and C, which vary in average molecular weight at shear rate (0.1 – 1000 s−1) and temperature (20°C– 60°C). Fifteen polymer solutions with different concentrations are made from the three products and screened through three evaluation stages. The first stage is measuring the bulk shear viscosity of the polymer solutions in the rheometer. The second stage is conducting single-phase polymer flooding through a novel micromodel. The stage of this approach applies the results from the earlier stages by running two-phase flooding experiments that implement polymer flooding for reservoir conditions of an oil field in Oman. The micromodel structure used in this work is generated based on X-ray micro-computed tomography (μCT) images of a Bentheimer core plug. Thus, the micromodel's porosity, permeability, pore, and grain size distribution are similar to the core plug. This characteristic gives an upscaling potential to a larger scale, such as core plug or even a field implementation. A database with bulk shear viscosity and model fits (Power law & Carreau) is generated from the rheometer measurements for polymers A, B, and C. A novel 3D surface model that relates the shear rate, temperature, bulk viscosity, and concentration is developed from the data in the first stage. The single-phase flooding experiments allow the investigation of the behavior of polymer in porous media under shear and extensional flow. Furthermore, the comparison of bulk shear viscosity and in-situ viscosity shows the potential to support the analysis of an empirical constant (C-factor). In addition, polymer injectivity and retention are investigated by analyzing the pressure drop and residual resistance factor after each single-phase polymer flooding experiment. The last stage of this work provides the improvement of displacement efficiency and the recovery factor, which measures the success of the approach. The novelty of this approach is the utilization of the linear Bentheimer micromodel for delivering an efficient polymer screening process. This micromodel reflects similar rock properties as Bentheimer rocks, which provide the potential to upscale the results from microfluidics to reservoir rocks. In addition, the novel 3D surface model developed in this work allows comprehensive screening, which is accomplished through combining the parameters required in polymer evaluation at one domain.