Core to Pore Scale Visual Analyis of Mixing Process in the Presence of Interface Between Heavy-Oil and Solvent
Bibliographic record
Abstract
Abstract Solvent injection, which is the only alternative to thermal methods to reduce the viscosity of heavy-oil, requires an effective solvent distribution in the reservoir to achieve the maximum oil-solvent contact. The dilution process, however, becomes slower as oil gets heavier. In this case, an initial interface exists between oil and -liquid or gas- solvent (similar to ultralow immiscible fluids cases). In case of heterogeneous reservoirs (fractured carbonates or wormholed oil sands), the diffusive mixing between the solvent in the fractures/wormholes and matrix oil requires longer contact times. Hence, an initial interface between the solvent and oil may exist and, depending on the wettability conditions, the existence of water and oil/solvent type, capillary imbibition (liquid solvent) or drainage (gas solvent) transfer into the matrix may take place. Intrusion of oil by capillary imbibition accelerates oil recovery reducing the time to get the oil and solvent contacted in order for the dilution (mixing) process to start. To investigate this phenomenon and perform a parametric analysis, an experimental design was developed focusing on analyzing the oil-solvent mixing zone mechanisms. A wide range of oil types (50cp to 100,000cp) and solvents (heptane and decane) were used. Experiments were performed on oil saturated 3 × 7 cm 2-D glass (core scale) and glass capillary tubes by soaking them into solvent under static conditions. To identify the mixing process (by color gradient) and distinguish the phases, advanced illumination and photographic techniques were applied using UV light and coloring the solvent. The followed experimental approach employed visual models at core and pore scale levels and successfully displayed the existence of both capillary imbibition and diffusion mechanisms in a solvent heavy-oil system. To what extent capillary imbibition could occur and assist in the recovery by miscible interaction was clarified for different oil, solvent, and wettability conditions. The results revealed that the solvent injection process might be enhanced by other mechanisms (imbibition or drainage) in heterogeneous reservoirs, which is usually neglected in modeling studies. Initial capillary imbibition took place if the glass surface was more solvent-wet than the original oil. Diffusive mixing followed by convective mixing occurred. Time periods corresponding to different recovery mechanisms were identified for different wettabilities and oil viscosities.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.005 | 0.001 |
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".