Determination of Mass Transfer Coefficient of Methane in Heavy Oil-Saturated Unconsolidated Porous Media Using Constant-Pressure Technique
Bibliographic record
Abstract
Measuring the solubility and diffusivity of methane in porous media saturated with oil is critical for analyzing the process of solvent-based recovery of heavy oil reservoir. In this study, a modified pressure-pulse decay (PPD) method is presented to measure the mass transfer coefficients of methane in porous media saturated with heavy oil as well as the solubility and diffusivity of methane in bulk oil under the same experimental conditions as those used in a comparison. The experiments are conducted under constant boundary pressure in a PVT cell, and the pressure is controlled using an auto pump, which continuously compresses the volume of an intermediate container. The accumulated volume change instead of the pressure change is recorded with time. The nonequilibrium boundary condition (BC) model is used to analyze the experimental process. The general solution of the mathematical model is derived using the Laplace transform and the approximate analytical solution of the accumulated dissolved gas is further presented for post processing of the experimental data. The mass transfer coefficients are estimated through using a multilevel single-linkage (MLSL) method to match the approximate solution with the recorded experimental data. The estimation of the parameters shows that the mass transfer coefficients are pressure dependent and that a high boundary pressure contributes to the mass transfer of methane in heavy oil due to a reduction in viscosity or density. The interface mass transfer coefficient ( k int ) and interface saturated concentration ( c int ) in porous media saturated with oil and bulk oil are almost the same under the same experimental conditions. The sensitivity analysis shows that the increase of the effective diffusion coefficient ( D eff ) and k int contributes to enhancing the rate of mass transfer in the oil phase and that Henry’s law constant ( H ) has no effect on the equilibrium time but only affects the initial saturated concentration at the interface or the total dissolved gas. The modified PPD method is robust, efficient, and easy to use in the laboratory.
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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 | 0.000 | 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 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".