Effect of Sodium Citrate and Calcium Ions on the Spontaneous Displacement of Heavy Oil from Quartz Surfaces
Bibliographic record
Abstract
Abstract The dynamic displacement of heavy oil from solid surfaces by water plays a significant role in the oil recovery process. In this work, a bitumen–water–quartz system was applied to study the effect of sodium citrate (Na3Cit) and calcium ions (Ca2+) on the dynamic displacement of bitumen from quartz surfaces. It was found that the addition of Ca2+ slowed down the bitumen displacement rate and generated daughter droplets during the receding process. In contrast, the presence of Na3Cit not only accelerated the displacement of bitumen from quartz surfaces but also led to a smaller water contact angle at the end of the experiments. Moreover, Ca2+ ions were chelated by the added Na3Cit, which counterbalanced the detrimental effect of Ca2+ on the bitumen displacement. The reduced interfacial tension of the bitumen–water interface and the increased negative charges on both bitumen and silica surfaces by Na3Cit were considered as the reasons for the improved bitumen displacement process. To better understand the underlying physics, both the hydrodynamic (HD) model and the molecular kinetic (MK) model were employed to analyze the dewetting dynamics of heavy oil from quartz surfaces under the effect of Ca2+ and Na3Cit.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".