Heavy Oil Recovery Mechanisms by Surfactant, Polymer and SP in a Non-Linear System
Bibliographic record
Abstract
Abstract The aim of this work is to evaluate the micro-displacement mechanisms associated with heavy oil recovery by water and chemical flooding in a non-linear system (2D Model). To evaluate the effect of sweep efficiency improvements with no local pore level trapping of fluids, a 2D neutral water wet Hele-Shaw cell is used to visualize the dominant mechanisms of surfactant, polymer and their combinations to enhance heavy oil recovery. Waterfloods were conducted as a base line, and compared to surfactant, polymer and SP floods at different injection stages (secondary and tertiary) and under variable injection rates. Post-breakthrough oil recovery and pressure drop during the water flood and chemical flood were evaluated with the analysis of images which show the distribution of the fluids in the cell. The results demonstrated that in waterflooding, oil pinches off the pre-formed water fingers and allows the formation of snap-off which divert further water to un-swept zones. Oil is produced discontinuously because of snap-off effects, with production of oil related to small pressure spikes in the system. This mechanism was also observed in polymer displacements. This observation can explain viscous flow of oil and discontinuous oil and water production after breakthrough in a heavy oil waterflood. Oil stripping and zones of low IFT, in the form of O/W emulsions were mechanisms observed in surfactant and SP flooding. Such emulsions are present in secondary fingers that then propagate and sweep new areas of the cell. The synergy between polymer and surfactant leads to a slightly better sweep efficiency in the cell by stripping oil and stabilizing the flood front compared to surfactant or polymer alone. Injection rate has also an impact in the flow stability and formation and flow of emulsions. At higher injection rates, flow is more unstable and leads to a less oil recovery. Multiple tests under the same conditions revealed the reproducibility levels of each displacement process. The novelty of this study is that it provides insights into fluid flow behavior in diverging flow paths as observed in 2D systems, as opposed to linear core floods that have limited flow pathways. In particular, these visual observations help to illustrate the role that surfactants can play in heavy oil systems, with and without the addition of polymer.
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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) | 0.001 | 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 | 0.001 |
| 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".