Phase Behaviour of Solvents/Heavy Oil Systems at High Pressures and Elevated Temperatures
Bibliographic record
Abstract
Abstract In this paper, techniques have been developed to determine multiphase boundaries of solvent(s)/heavy oil mixtures at high pressures and elevated temperatures in pressure-temperature (P-T), enthalpy-temperature (H-T), and pressure-enthalpy (P-H) phase diagrams, respectively. Theoretically, the Peng-Robinson equation of state (PR EOS) incorporated with a new alpha function as well as the previously developed enthalpy calculation algorithm are used to predict the multiphase boundaries of the solvent(s)/heavy oil systems by characterizing the heavy oil as a single pseudocomponent. The PR EOS associated with the newly developed alpha function is found to be accurate in reproducing the experimentally measured VL1L2 (V represents the vapour phase, L1 denotes the high density hydrocarbon-rich liquid phase, and L2 refers to the low density CO2 liquid phase) three-phase boundary pressures with an overall absolute average relative deviation (AARD) of 2.01% and maximum average relative deviation (MARD) of 3.54%, respectively. In addition, the VL1L2 three-phase boundaries are expanded and tended to move toward the region with higher temperatures and lower pressures in the P-T phase diagram with the addition of either C3H8 or n-C4H10 to CO2/heavy oil systems compared to those of only CO2 exists in heavy oil systems. The enthalpy changes rapidly with variation of temperature in both H-T and P-H phase diagrams within the three-phase region. Either two-phase (VL1) or three-phase (VL1L2) isenthalpic flash calculations can be performed straightly to determine phase fractions and compositions together with system temperature without conducting the stability analysis for a provided solvent(s)/heavy oil mixture at a constant enthalpy and pressure with the constructed H-T phase diagram.
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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 | 0.000 |
| 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) | 0.001 | 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".