Pembina Cardium CO2 Monitoring Project, Alberta, Canada—Geochemical interpretation of produced fluid compositions
Bibliographic record
Abstract
A CO 2 monitoring pilot was initiated at the Penn West Energy Trust CO 2 EOR operations within the Cardium formation of the Pembina Field. The Penn West Pembina-Cardium CO 2 EOR Monitoring research program focused on well integrity, local/ regional geology and hydrology, extensive monitoring of CO 2 and short and long predictive modeling. The geochemical modelling program of the Penn West Monitoring Project quantified the chemical reactions that occur between the gas -oil-water-rock within the reservoir prior to, during, and following CO 2 injection. An equilibrium speciation geochemical model was used to examine the field produced water compositions. Many of the produced waters are undersaturated with respect to calcite. This is most easily explained when mixtures of waters of quite different chemical compositions are produced from a single producing well. This observation has important implications for the interpretation of produced water compositions and demonstrates that flow within the reservoir must be understood to fully interpret the chemistry signatures. A reaction mass transfer model was used to evaluate the chemical processes in the reservoir (short and long term) and to evaluate the thermodyn amic data base. It established that the dominant reaction controlling the short term water composition was ion exchange reactions, coupled with calcite dissolution and CO 2 transfer from the oil phase. It was also used as a predictive tool to estimate them ineralogical reactions which will ultimately be responsible for the long term trapping of the injected CO 2 . GEM-GHG was used to calculate the chemical processes occurring during the various phases of hydrocarbon recovery, including the predicted evolution of produced water compositions, and th e results compared to field measurements. Discrepancies between the modeled and the measured field data can be used to refine the model, improving our understanding of chemical processes in the reservoir. The geochemic al models allow an assessment of the amount of CO 2 trapping in each of the major units in the reservoir. There are large uncertainties in the absolute value of the amounts, but they allow a direct comparison between trapping mechanisms and a direct comparison between the trapping in each reservoir unit. This work represents a first study to demonstrate the potential of using geochemical sampling and measurements and integrating them with reservoir models for secondary and tertiary oil recovery.
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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 | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".