An Experimental Study of Steam-Assisted Gravity Drainage
Bibliographic record
Abstract
Summary In this paper we present a large-scale experimental study of the compositional effect on produced bitumen properties in steam-assisted gravity drainage (SAGD). The SAGD experiment used a sandpack in the cylindrical pressure vessel that was 1.22 m in length and 0.425 m in internal diameter. The pore volume of the sandpack was 58 L, and the porosity and permeability were 0.33 and 5.5 darcy, respectively. The sandpack was initially saturated with 93% bitumen and 7% deionized water. The SAGD experiment after preheating was operated mostly at a steam injection rate of 35 cm3/min (cold-water equivalent) at 3,600 kPa (244°C). The produced fluids (gas, oil, and water) were analyzed; for example, 10 oil samples were analyzed in terms of carbon number distribution (CND), the asphaltene content, density, and viscosity to investigate the compositional change of the produced bitumen. After the experiment, the sandpack was excavated, and samples were taken for analysis of solid, water, oil, asphaltene, and sulfur contents. Experimental data (e.g., propagation of a steam chamber and production of oil and water) were history matched using a numerical reservoir simulator. The produced bitumen was lighter and contained 1- to 5-wt% less asphaltenes than the original bitumen. Also, the remaining oil inside the steam chamber contained 6-wt% more asphaltenes. As a result, the produced bitumen was 1- to 6-kg/m3 less dense than the original bitumen. This is an increase in API gravity from the original 7.9° to 8.6°. In the actual operations, bitumen is diluted with condensate to decrease the oil viscosity for pipeline shipping. This decrease in bitumen density corresponds to a decrease of the diluent cost by 5 to 10%. The produced bitumen became less dense with increasing steam-chamber volume. Results were history matched with a simulation model that considers capillary pressures to properly model the mixed flow regimes of oil/water countercurrent and cocurrent flow with an expanding steam chamber. The history-matched simulation indicated that the progressively decreasing density of the produced bitumen can be attributed to the vaporization of the relatively volatile components in the remaining oil and condensation of those components near the chamber edge.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".