Effects of Salinity and Individual Water Ions on Crude Oil-Water Interface Physicochemical Interactions at Elevated Temperature
Bibliographic record
Abstract
Abstract SmartWater flooding processes through injection of optimized chemistry waters are lately becoming popular for enhanced oil recovery (EOR) in carbonate reservoirs. In this study, we describe the results from a series of experiments, including interfacial tension, interfacial shear rheology, and droplet coalescence times, at elevated temperature to determine the effects of both salinity and individual water ions on different microscopic scale interactions occurring at the crude oil-water interface. In addition the results from microscopy imaging of the interface and zeta potential/oil droplet size distributions in crude oil-water/brine emulsions were also reported at the ambient temperature. We measured various crude oil-brine physicochemical changes and effects using a variety of experimental techniques including attention tensiometer, double wall ring shear rheometer, Brewster angle microscope, ZetaPhoremeter, Zetasizer Nano and integrated thin film drainage apparatus (ITFDA). The reservoir crude oil was used and ionic strengths of different brines were varied from high salinity seawater (56,000 ppm TDS) to pure deionized water. The dynamic and equilibrium interfacial tension (IFT) of crude oil-brine interfaces were found to be lower than that of the crude oil-DI water interface. Both the 10-times reduced salinity seawater and 10-times reduced salinity seawater enriched with sulfates showed relatively higher IFT, while the initial rate of IFT change with time was observed to be the lowest with sulfate-rich brine. The interfacial rheology results showed that the transition times - for the interface to become elastic-dominant from a viscous-dominant regime - were found to be the lowest for low salinity sulfate-rich brine and the greatest were with high salinity multivalent brines. The coalescence times determined for crude oil droplets in different brines showed delayed coalescence with DI water and sulfate-rich brine, whereas the fastest coalescence was observed with the high salinity multivalent brine containing calcium and magnesium ions. All these results on IFT, interfacial shear rheology and crude oil droplet coalescence times obtained at elevated temperature agreed well with previously reported ambient temperature data to indicate similar trends for different water ion interactions occurring at the crude oil-water interface. The microscopy imaging results at ambient temperature showed formation of aggregates with DI water, and two low ionic strength brines to demonstrate the better activity of interfacially active molecules to result in stable interfaces. The highest negative zeta potentials were observed in DI water and sulfate-rich brine at ambient temperature. The oil droplet diameters measured in crude oil/brine emulsions showed the lowest droplet sizes with DI water and sulfate-rich brine, respectively. The measured data from different experimental techniques at both elevated and ambient temperature therefore showed good consistency with each other to demonstrate the adverse impact of sulfate ions and importance of having certain salinity and specific key ions, such as calcium and magnesium, in the aqueous phase to result in favorable interactions at crude oil-water interface. Such tailored water recipes can promote oil phase connectivity in SmartWater flood by enhancing the coalescence between released oil droplets.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".