Injection of Nanofluids with Fluorosurfactant-Modified Nanoparticles Dispersed in a Flue Gas Stream at Very Low Concentration for Enhanced Oil Recovery (EOR) in Tight Gas-Condensate Reservoirs

摘要

The main objective of this work is to evaluate the effect of nanofluids formed by surface-modified nanoparticles with a fluorosurfactant dispersed in a flue gas stream at low concentrations as an enhanced oil recovery (EOR) process applied to a tight gas-condensate reservoirs (TGCR). This research is a continuation of our previous study (doi.org/10.1021/acsami.9b22383) in which nanoparticles of gamma-Al2O3 and MgO modified with a short-chain fluorinated anionic surfactant (SY) at 30% by weight were developed. Here, the nanomaterials were used for preparing nanofluids (NF) at different concentrations to improve the mobility of the liquids in TGCR. Contact angle tests under high-pressure and high-temperature (HPHT) conditions were performed from 5 to 276 bar and at a constant temperature of 80 degrees C through the sessile drop technique to select the best nanofluid that generates a gas-wettability for EOR operations. Interfacial tension (IFT) measurements at high pressure (276 bar) and high temperature (80 degrees C) were also conducted to determine the selectivity of nanofluids to locate at the rock-fluid interface. The nanoparticles with superior performance were further evaluated through coreflooding tests at reservoir conditions of overburden pressure of 448 bar, pore pressure of 276 bar, and a temperature of 80 degrees C in a tight sandstone outcrop. The best results found for the contact angle and IFT at HPHT were obtained for the nanofluid of gamma-alumina nanoparticles functionalized with fluorosurfactant at 30% by weight (AlSY30) dispersed in water at a concentration of 300 mg.L-1 (AlSY30-NF). The contact angle results obtained at reservoir conditions at 276 bar and 80 degrees C were 122 +/- 2 degrees and 119 +/- 1 degrees for water and oil, respectively. Also, IFT tests showed the preference of these nanofluids to be located at the rock-fluid interface and thus generate greater performance from the injected treatments to modify the rock wettability. These results are supported by a more than 95% increase in the energy binding to the oil/brine (Delta E) interface of AlSY30 nanoparticles than MgSY30 nanoparticles. A novel coreflooding test was performed by dispersing the nanofluid at different concentrations (from 0 to 300 mg.L-1) in a flue gas stream. A low concentration of 10 mg.L-1 resulted in a residual oil saturation (Sor) reduction of 57% and an increase in oil recovery of approximately 23% relative to the flue gas in the absence of nanofluid. A synergistic effect between a wettability alteration and a decrease in IFT occurred due to nanofluid dispersal in the flue gas stream. The results obtained in this study are expected to promote innovative and efficient technology for dispersed nanofluid injection as a recovery method in tightly condensed gas fields with excellent performance at low concentrations.