Front Self-Correction for In-Situ Combustion
Bibliographic record
Abstract
Summary Since it was discovered in the early 1920s, several improvements have been suggested for in-situ combustion (ISC) technology. Top-down combustion displacement is a process proposed for application with horizontal well technologies. In this configuration, air is injected near the top of the reservoir, close to the overburden, through a horizontal well or a number of vertical wells. Fluids are produced from the reservoir through horizontal wells placed near the bottom of the reservoir. In this configuration, the combustion front moves downward with gravity and displaces fluids to the production well. Combustion front formation and its stability are major concerns in this arrangement. While the short distance between injector and producer addresses the cold oil blocking problem in the reservoir, it has the potential to create air fingers, which could prevent stable advance of the combustion zone in a horizontal plane. Front self-correction must occur to prevent oxygen from fingering to the production wells. To prove this idea, experiments at reservoir pressure were carried in a 2D SAGD model with Athabasca bitumen. Air was injected into the SAGD steam chamber from the top, and fluids were produced from the bottom. Front advancing directions were monitored by a series of thermocouples located inside the model. It was found that the combustion zone starts spreading horizontally in the model until it reaches a limiting point, then it starts moving downward as a horizontal front. Despite heterogeneity of the oil saturation and relative permeability in the steam chamber and unswept zones, the combustion front moved almost as a horizontal plane and no sharp fingers were recorded in the experiments. These experiments show that stable top-down combustion is feasible.
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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) | 0.001 | 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 | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".