In Situ Combustion as a Followup Process to CHOPS
Bibliographic record
Abstract
Abstract There are a large and growing number of Western Canadian heavy oil deposits that have been depleted using primary cold production (CHOPS) methods. At their economic limit these methods leave behind 85 % to 90 % of the OOIP while significantly altering the reservoir conditions from their initial state. The oil remaining is a significant target for a follow up process; however, presently there is no demonstrated EOR process that can economically recover additional oil from these deposits in their current condition. The application of in situ combustion in a reservoir that has under gone CHOPS has several attractive features. The wormhole network created during primary production provides the injectivity required to initiate and sustain high temperature combustion. The interconnected wormhole channels between adjacent wells supplies a conduit for mobilized oil to flow to production well thus minimizing liquid blockage and ineffective conformance. To assess the potential of in situ combustion as a post CHOPS process a laboratory study was carried out examining the behavior of in situ combustion under conditions representative of the reservoir at the end of CHOPS. A total of seven physical simulation experiments were carried out in the Heavy Oil and Oil Sands laboratory of the Alberta Research Council (now part of Alberta Innovates – Technology Future). Test conditions of these experiments included high permeability channel vs. no high permeability zone, partially filled high permeability channel vs. completely open channel, dead oil vs. live oil dry combustion vs. wet combustion, and normal air vs. enriched air injection,. Results of the experiments are encouraging for the application of in situ combustion in CHOPS reservoirs. The high permeability wormhole channels provided injectivity to initiate and sustain combustion and the presence of the channel lead to improved conformance with no gravity overriding of the combustion front. Localized coke plugging of the channel prevented the combustion front from prematurely breaking through to the production well, even with a completely open wormhole channel.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.003 | 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".