Bibliographic record
Abstract
Abstract Unlike steam injection for heavy oil recovery, in situ combustion (ISC) process requires an extra-step, namely initiation of the process, the so called ignition operation. During ignition, an ISC front is generated near the air injection well and, thereafter, this front is propagated towards production wells. Air injection interruptions can be un-intentional or intentional, including one-day-per-month scheduled interruptions for cleaning oil from air lines exiting the compressors. Regarding air injection interruptions a question arises: can the process be resumed without initiating a new ignition operation? The paper attempts to provide clear answers to this question. The paper reviews information on more than 6 cases of air injection stoppage in the field, involving well instrumented dry ISC projects, conducted either in patterns or in a line drive system. Most of the cases are from Suplacu de Barcau (Romania) project, which is the world’s biggest ISC commercial project. The duration of air injection interruptions ranged from a few hours to 36 days. Performance before and after interruptions are analyzed in terms of changes in air injectivity, effluent gas composition and oil production. To support various field observations, essential results from simulation of the dry ISC process are also included; Temperature distributions during air injection stoppage were determined analytically for a linear system and numerically, for a radial system. In both cases a specific characteristic of the temperature re-distribution was noted, namely the move/shift of the peak temperature inside the former burned out zone. Some additional conclusions regarding the stability of the process as function of elapsed time since the initiation of the process were also formulated. Stability of the process was investigated for air injection interruptions of up to 90 days. Finally, a case is presented involving a pressure cycling ISC process; stability performance of the Morgan ISC project (Alberta, Canada) during its 6-year field piloting is discussed. In this project, interruptions of air injection of up to 21 months occurred. Inherent limitations in evaluating the stability performance are reviewed given the very complicated nature of this dry ISC process in which reservoir pressure was cyclically increased and oil was allowed to flow through the burned out zones during the air injection
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".