Determining the Most Profitable ASP Flood Strategy for Enhanced Oil Recovery
Bibliographic record
Abstract
Abstract While chemical floods have proven technically successful, the high cost of chemicals makes it challenging to develop a costeffective tertiary process. If high interfacial tension (IFT) exists between the oil and water phases, the resulting capillary forces will resist externally applied viscous forces. This could cause the injected water and chemicals to bypass the residual oil and go to waste. The experimental studies presented here include reservoir fluid characterization, IFT measurements, and coreflood tests; all critical elements in designing a cost-effective alkaline/surfactant/ polymer (ASP) injection strategy. Coreflood tests used either sandpacks or composite reservoir cores with a selected medium crude oil. Injected surfactant concentration, slug size, chasing fluid, and residual oil saturation were the varied parameters. The optimal surfactant concentration of 0.15 wt% and slug size of 0.5 pore volume (PV) obtained relatively high oil recovery while maintaining a favourably high displacement efficiency ratio. Incremental recovery was 23 – 41% initial oil-in-place (IOIP) in sandpack tests and about 16% IOIP with reservoir cores. Overall, these coreflood results indicate that ASP flooding is a suitable enhanced oil recovery method for medium oil if the right chemical concentration and slug size are selected. Introduction The use of ASP flooding to recover oil left behind by waterflooding has become more common in recent years. Several significant developments have made ASP flooding a viable option for field enhanced oil recovery (EOR) projects and more attractive than polymer or micellar/polymer flooding. First, because world oil consumption continues to grow while production in many mature fields continues to decline, oil prices are predicted to stabilize above US$20/bbl. Second, newly developed cheaper surfactants have reduced the cost of EOR formulations by 40 to 60%, while maintaining the same high oil recoveries obtained using more expensive surfactants. The incremental cost per barrel of oil produced has been reduced to a reasonable level, between US$1.44 and $5.83(1). Third, chemical flooding can be evaluated in the oil field faster and more economically than in the past using the single-well EOR pilot test and field-scale numerical simulations. Fourth, waterfloods in most mature reservoirs have experienced early water breakthrough and have reached their economic limit. Therefore, oil companies have to consider applying new EOR technologies to increase recovery factors in such fields. The proven medium oil resource in southwest Saskatchewan, estimated at 534.5 × 106 m3, is located in reservoirs characterized by thin pay and shaly sand. Primary and secondary methods have recovered an estimated 25% IOIP from these reservoirs(2) and are nearing their economic limit. There has been little development of this resource by EOR technologies. The Saskatchewan Research Council (SRC) has conducted extensive studies to develop ASP flooding for a selected reservoir- Instow-with reserves of about 22.1 × 106 m3 of medium oil originally in place. Instow field is located in Ranges 18 and 19 of Townships 9 and 10 in southwest Saskatchewan. This moderate- permeability sandstone reservoir (Upper Shaunavon sand at a depth of 1,370 m) was discovered in 1954 and has been waterflooded since 1959.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".