CAPILLARY DESATURATION TENDENCY OF HYBRID ENGINEERED WATER BASED CHEMICAL ENHANCED OIL RECOVERY METHODS
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Date
2021
Authors
Shakeel, Mariam
Samanova, Aida
Pourafshary, Peyman
Hashmet, Muhammad Rehan
Journal Title
Journal ISSN
Volume Title
Publisher
Energies
Abstract
Several studies have shown the synergetic benefits of combining various chemical enhanced
oil recovery (CEOR) methods with engineered waterflooding (EWF) in both sandstones and carbonate
formations. This paper compares the capillary desaturation tendency of various hybrid combinations
of engineered water (EW) and CEOR methods with their conventional counterparts. Several coreflood
experiments were conducted, including EW-surfactant flooding (EWSF), EW-polymer flooding
(EWPF), EW-alkali-surfactant flooding (EWASF), EW-surfactant-polymer flooding (EWSPF), and EW alkali-surfactant-polymer flooding (EWASP). Capillary numbers (Nc) and corresponding residual
oil saturation (Sor) for each scenario are compared with capillary desaturation curves (CDC) of
conventional CEOR methods from the literature. The results indicate that hybrid EW–CEOR methods
have higher capillary desaturation tendency compared to conventional methods. The capillary
numbers obtained by standalone polymer flooding (PF) are usually in the range from 10−6
to 10−5
,
which are not sufficient to cause a significant reduction in Sor. However, the hybrid EW-polymer
flooding approach considerably reduced the Sor for the same Nc values, proving the effectiveness
of the investigated method. The hybrid EWASP flooding caused the highest reduction in Sor (23%)
against Nc values of 8 × 10−2
, while conventional ASP flooding reduced the Sor for relatively higher
Nc values (3 × 10−3
to 8 × 10−1
). Overall, the hybrid methods are 30–70% more efficient in terms of
recovering residual oil, compared to standalone EWF and CEOR methods. This can be attributed to
the combination of different mechanisms such as wettability modification by EW, ultralow interfacial
tension by alkali and surfactant, reduced surfactant adsorption by alkali addition, and favorable
mobility ratio by polymer. Based on the promising results, these hybrid techniques can be effectively
implemented to carbonate formations with harsh reservoir conditions such as high salinity and
high temperature.
Description
Keywords
Type of access: Open Access, capillary desaturation, chemical flooding, engineered waterflooding, hybrid enhanced oil recovery
Citation
Shakeel, M., Samanova, A., Pourafshary, P., & Hashmet, M. R. (2021). Capillary Desaturation Tendency of Hybrid Engineered Water-Based Chemical Enhanced Oil Recovery Methods. Energies, 14(14), 4368. https://doi.org/10.3390/en14144368