Physical and Numerical Modeling of Capillarity and Aqueous Phase Saturation Effects on the Rate of Solvent Mass Transfer in Boundary Layer in Heavy Oil Reservoirs
Bibliographic record
Abstract
Abstract Solvent injection has emerged as a recovery technique in low pressure and shallow heavy oil reservoirs in cold systems or in combination with steam in steam-based thermal processes. The performance of solvent-based processes strongly depends on the rate of mass transfer in the boundary layer on the edge of solvent and/or steam chamber. Therefore, understanding of the mass transfer phenomena is required for realistic prediction of the performance of solvent-based or solvent-assisted processes. This study was designed to investigate the capillarity and aqueous phase saturation effects on the rate of mass transfer occurring in the boundary layer on the edge of the solvent chamber. In this study, a new experimental approach was designed and developed to eliminate any disturbance in the boundary layer to experimentally simulate the gravity drainage process in vapor extraction process at two different drainage heights. The porous media and oil-solvent characteristics required for history matching study were determined by measuring the capillary pressure and pore size distribution of sand packs, as well as conducting a complete phase behavior study to determine the properties of the oil-solvent system in a wide range of solvent concentrations. Total number of 12 experiments was conducted in three different sandpacks with different pore size distributions, but similar range of permeabilities (i.e., 5.1-6.5 D) to investigate the effect of capillary forces on the mass transfer phenomena. Conducted analytical and numerical modeling showed that the effective diffusion coefficient was in the range of 4.91×10-8-1.10×10-5 cm2/s. In absence of immobile water saturation, effective diffusion coefficient was in the range of 4.91×10-8-7.89×10-6 cm2/s. In presence of immobile of aqueous phase saturation, the effective diffusion coefficient varied between 2.96×10-6 and 1.10×10-5 cm2/s. The comparison between the calculated effective diffusion coefficients and reported molecular diffusion in literature by different researchers confirmed that the velocity-dependent term in convective dispersion does not play a major role at higher capillarities in heavy oil systems, i.e., lower permeability range compared to other studies (i.e., >100 D). This study highlights the need for selection of a realistic mass transfer coefficient for the simulation of the performance of the solvent injection processes.
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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".