Bibliographic record
Abstract
Abstract In recent years, substantial progress has been made in the theoretical treatment of hydrocarbon dissolution in water, near the critical point of water (374 ° C). At these temperatures, water becomes a solvent for gases including the lower hydrocarbons, and possibly higher hydrocarbons. The SAGD process is currently the only viable method for in-situ recovery of Canada's Athabasca oil sands deposit, a deposit of high viscosity oil in unconsolidated sand. Recent studies have sought to understand modifications at lower steam pressures and gas injection. Most recently, the idea of solvent co-injection has been under discussion. In the present paper, the predictive capabilities that have been developed for gas production in the SAGD process are studied in conjunction with the chemical kinetics and mechanisms of solvolytic reactions. The reactions that produce hydrogen sulphide and carbon dioxide, generally referred to by the name "aquathermolysis", are in fact solvolytic reactions by their nature. The results of this work suggest strongly that the production of the acid gas gases, hydrogen sulphide and carbon dioxide, will be suppressed in SAGD operations if a solvent is coinjected. The work has implications for the need for sulphur recovery plants in SAGD projects that are considered for solvent co-injection. Introduction In 2001, Thimm1 proposed that gas production in SAGD proceeds via a dissolution mechanism. Gases are dissolved in the produced liquids, and break out of solution in the wellbore and facilities. There has been no case reported so far where it is necessary to assume free gas production in SAGD in order to account for observed gas production or composition. The rationale is as follows: The distribution coefficient (K-value) of a solute gas in equilibrium with a solvent is given by Equation (1) (Available in full paper) where yi and xi are the mole fractions of solute i in the gas and liquid phase respectively. Henry's Law may be stated as Equation (2) (Available in full paper) In this form, the unit of the Henry's Law coefficient is that of pressure, as is evident from inspection. For the purpose of this work, all Henry's Law constants are given in units of mPa. The equation shows that the K-values are related to the Henry's Law constant. Determination of Henry's Law Constants Henry's law coefficients for gases in solvents normally follow a power law known as the Valentiner equation T, T(2), T(3), However, at elevated temperatures, this equation begins to fail at about 175 °C, and could only be used for the lowest steam pressure situations. Above this temperature, deviations become progressively larger, because an asymptotic behaviour of the Henry's Law constant near the critical point of water makes an increasingly important contribution. Above °1750C, the specific volume of water begins to fall significantly from the normal 55.56 mole/L, and Harvey and Levelt Sengers2 have shown a linear relationship between Equation (3) (Available in full paper) in the range °1750C and the critical point of water at °3740C.
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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".