Factors Affecting SAGD Performance in Dipped Bed Extra Heavy Oil Reservoirs
Bibliographic record
Abstract
Abstract In reservoirs with certain dip, the steam chamber advances different than in conventional SAGD projects. Since the horizontal permeability is normally higher than vertical permeability and because reservoir pressure is lower toward up-dip; an early lateral growth of the steam chamber should be promoted to the uppermost reservoir position. If horizontal permeability controls the gravity drainage instead of vertical permeability, it is thought that a good gravity drainage process in dipped reservoirs could be achieved, even in cases were vertical transmissibility is poor. However, if there is mobile water within the reservoir, then the steam easily flows up-dip and away from the producer well diminishing the hot oil draining to the producer and affecting the SAGD well's performance. The factors affecting SAGD efficiency in a dipped-bed extra heavy oil reservoir (6.5°API) located in southern llanos Colombia have been analyzed. An important extra heavy oil accumulation toward the outcrop of main production sands was encountered. The reservoir temperature is low (100°F) so bitumen viscosity is high (>100.000cp). In addition, oil saturation could be lower than is the standard for commercial projects in some areas. A reservoir characterization was done using data from 18 wells. Information from basic and special logs, routine and special core analyses as well as displacement tests was used to build a robust numerical model. Several numerical simulations were run to address the performance of SAGD under such conditions. Particularly, the amount of mobile water and dip, play a major role in SAGD efficiency since the steam chamber behaves accordingly to both parameters. Numerical simulations done in this work have shown that SAGD thermal efficiency in dipped bed reservoirs is dramatically affected by energy losses toward the uppermost reservoir position since the steam tends to flow up dip far from producer wells. This effect is amplified when mobile water is within the porous medium. Different strategies to improve SAGD efficiency were explored by numerical simulation. Well configuration was changed from parallel to staggered; electromagnetic heating was evaluated as well as hybrid processes. Hybrid processes could certainly open doors for economic development of highly viscous heavy oil reservoirs with mobile water saturation.
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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) | 0.001 | 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".