PERFORMANCE AND IMPACT OF POLYMER NANOCOMPOSITES ON ENHANCED OIL RECOVERY

The increasing human population has given rise to greater energy demand which continues to place a burden on energy production worldwide. This has intensified the need for innovation, both in the petroleum industry and renewable energy sector. The petroleum industry has in recent years experienced the gradual disappearance of “easy oil.” In addition to this, only about 30% of the original oil in place (OOIP) can be extracted using conventional techniques, leaving about 70% of crude oil in the reservoir after primary and secondary oil recoveries have been exhausted. For this reason, new approaches to oil recovery called enhanced oil recovery (EOR) have been developed to recover more oil from existing reservoirs. One of the most common methods is chemical EOR, which involves the injection of chemicals into the reservoir to increase the overall efficiency of the process. In this work, innovative mixtures of polymer nanocomposites (PNC) were explored for viscosity and core flooding experiments as a route for chemical EOR. Three polymers: xanthan gum, guar gum and gum arabic; and two nanoparticles: alumina and silica, were mixed in different proportions and used for core flooding experiments with a reservoir permeability tester (RPT). Cupric nanoparticle was used in addition to the two other nanoparticles and three polymers for viscosity tests using a viscometer. The effects of temperature, salinity, shear rate, polymer concentration and nanocomposites on viscosity were investigated. Spectral analysis of the polymers was done using Fourier-Transform Infrared (FTIR); thermal stability of the polymers was tested using thermogravimetric analyzer (TGA). Scanning Electron Microscope (SEM) was used to obtain micrographs of the nanoparticles and study the morphology of core plugs used in the flooding process. The results showed that the viscosity of the polymers increased with polymer concentration, with xanthan gum having the highest viscosity among the three polymers (1645 cP at 1.0% w/w) and gum arabic having the lowest viscosity (180 cP at 1.0% w/w). For all the nanocomposite combinations considered, the addition of the nanoparticles caused their viscosities to increase. The cupric oxide nanoparticles produced the highest effect on the viscosities of the polymer nanocomposites. As the temperature increased from 30 to 90℃, the viscosities of the polymers were observed to reduce; the polymer viscosities also reduced with salinity. In the core flooding experiments, xanthan gum, guar gum and gum arabic achieved total oil recoveries of 62.8, 54.2 and 52.5%, respectively: Eclipse software provided validation for the observed trend. Across the six PNC used for core flooding, alumina had a greater impact on oil recovery than silica. Also, xanthan gum-alumina PNC recorded the highest recovery of 72.8%. The TGA results showed that gum arabic had the greatest stability above 70℃, while xanthan gum had the lowest. It was deduced from the SEM images that each nanocomposite impaired the permeability of the core plugs to some extent. The results obtained in this work make a strong case for the adoption of polymer nanocomposites for EOR, especially for nanocomposites containing gum arabic, which is locally produced and available in large quantities