Field Application of Unconventional Foam Technology: Extension of Liquid CO2 Technology
Bibliographic record
Abstract
Abstract Liquid CO2-based systems have been pumped as fracturing fluids in North America since the early 1980s and liquid CO2/N2 system from 1994. The fluids have been used in more than 1000 wells in a variety of formations having permeability values from 0.1mD to 10 Darcies, depths in excess of 3000 m and bottom-hole temperataure (BHT) from 10 to 110 °C. The chemistry and physics of these fluids are intriguing and have been described before. Several attempts to increase the viscosity of liquid CO2 have been tried with little success. Here, a novel fluid is described that retains all the nondamaging aspects of liquid CO2 but with increased viscosity. This fluid is a foam of nitrogen in liquid CO2. It uses a CO2-soluble foamer that does not damage the formation and can be released into atmosphere without damaging the environment. The fluid does not include any other liquids, such as water, alcohol or hydrocarbons. The foam thus formed follows conventional foam physics (with respect to viscosity increase as a function of internal phase volume, etc.). Due to the limited amount of liquid CO2 used (around 20-25 volume% for a foam of internal quality of 75-80%), multiple jobs can be conducted on a single day making the system more cost-effective than the typical liquid CO2 fracturing system. A summary of the field use for shallow gas applications in Canada is described.
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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".