30 Years of Successful High-Pressure Air Injection: Performance Evaluation of Buffalo Field, South Dakota
Bibliographic record
Abstract
Abstract The Buffalo Field enhanced oil recovery project is the oldest, still active, air injection project in the United States. The combination of depth (8,500 ft), high pressure (4,200 psi), light oil (32 °API), high reservoir temperature (215 °F) and low permeability (1 to 20 md) carbonate formation makes this a unique air injection project, covering a large area (33,160 acres). The project's longevity attests to both its technical & economic success. Laboratory studies (combustion tube, miscibility pressure and swelling tests for various CO2-N2 mixtures) and feasibility studies including air injectivity testing were completed in mid-1977. The result of the pilot test was promising and the 2,240-acre Buffalo Red River Unit (BRRU) was formed in November 1978. As production response continued to be encouraging, the BRRU was expanded to 7,680 acres in May 1981. Two other EOR units, South Buffalo Red River Unit (20,800 acres) and West Buffalo Red River Unit (4,680 acres) were formed adjacent to BRRU, in 1983 and 1987 respectively. The three units currently have a total of 59 producers and 20 injectors. Oil production in all units has shown significant increase over its historical decline under continued primary. Peak production reached 3,030 BOPD in June 1991. Current production is 1,500 BOPD and injection is 30,500 Mcfd. Cumulative air injection through December 2009 is 262 Bcf and the incremental production due to air injection is about 18.1 Million barrels resulting in cumulative air utility of 14.5 Mcf/incremental barrel. This paper focuses on the technical aspects of the Buffalo EOR project, reviewing laboratory studies, production performance (1978 to 2009) and the impact of short radius horizontal drilling. It also includes estimates of the EOR barrels produced, how air utility and air retention have changed over time, and estimates of the burned volume in each of the units.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".