Evolution of formation water chemistry and geochemical modelling of the CO2CRC Otway Site residual gas saturation test
Bibliographic record
Abstract
The CO 2 CRC Otway Project Stage 2B field test was a residual CO 2 saturation and dissolution experiment carried out on the Paaratte Formation in the Otway Basin of Australia. During the 87 day test a downhole U-tube sampling assembly was used to collect formation water samples at various time intervals. The waters were analysed for chemical composition, dissolved gas content and stable isotopic composition of H and O. Changes in the chemical and isotopic composition of the formation water were observed from the initial baseline samples collected through to the conclusion of the test. Systematic reoccurrences of relatively large linear changes in the alkalinity, Ca 2+ , Fe 2+ , Mg 2+ and SiO2(aq) were observed during different test sequences. Similar behaviour occurred for the δ 18 O and δ 2 H values suggesting a complex system controlled by at least two processes. The chemical evolution was consistent with CO 2 -water-rock interactions, dominated by carbonate dissolution with some silicate dissolution. The mineral dissolution driven changes in water composition are overlain by what was clearly mixing of the injected and in situ formation water. The isotopic composition of the water was used to confirm the role of mixing and the calculated residual gas saturation values were broadly consistent with those derived by other methods. The extent of reaction in the relatively short time frame of the test was used to evaluate the capabilities of kinetics based reaction path models. The models were generated using published reaction rate data with commonly used assumptions regarding upscaling of reactive surface area. These assumptions consist of reducing the calculated geometric surface area that accounts for grain shape and roughness by factors of 100 to 1000 depending on the mineral habit. The numerical models provided a very good fit to the field data indicating that the rate data and the associated assumptions are relatively robust.
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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".