Dynamic Behavior of Asphaltene Deposition and Distribution Pattern in Fractured Porous Media during Hydrocarbon Solvent Injection: Pore-Level Observations
Bibliographic record
Abstract
Precipitation and deposition of asphaltene in reservoir rock can cause formation damage and reduce the fluid mobility, resulting in significant loss of hydrocarbon production. A detailed study on asphaltene deposition behavior in porous media improves the understanding of asphaltene-induced formation damage and provides the possible solutions for preventing and/or controlling formation damage. For advancements in understanding asphaltene deposition in fractured porous media, asphaltene deposition behavior was analyzed with the help of pore level observations during hydrocarbon solvent injection. Three types of hydrocarbon solvents (nC5, nC7, and nC12) were used for solvent injection for extra-heavy oil recovery (30 000 cP at 22 °C). A uniquely designed heterogeneous-fractured micromodel imitating the fractured porous media was used for pore level observation. A high-quality camera along with a microscope was utilized to capture images. SEM analysis was also performed on precipitated asphaltene to visualize the difference in the structure of the asphaltenes precipitated with different solvents. Observation through this study revealed that besides the amount of asphaltene deposition, the distribution pattern of asphaltene deposition could also be different when using various types of solvent. Besides decreasing the amount of asphaltene precipitation, the deposited asphaltene distributed more widely in the studied porous medium as carbon number of solvent increased (C5–C12). Moreover, it was noted that asphaltene could be deposited in different shapes that may or may not block the pore throat. The dominant flow mechanism (either diffusion dominant or viscous dominant) will affect the shape of deposited asphaltene. Asphaltene can be deposited perpendicular or parallel to the flow direction, which is in the form of parallel rope-shaped deposits. The perpendicular deposits (usually in dominant diffusion flow), mainly observed in small pore throat, can block the diffusion path. However, the parallel deposits (typically in viscous dominant flow) will not significantly impede the flow path. The results of this study improve our understanding of different aspects of asphaltene-induced formation damage in the fractured reservoirs such as susceptible locations of asphaltene deposition, different shapes of deposition which may or may not result in pore blocking, and the effect of flow behavior and heterogeneity on asphaltene deposition and formation damage.
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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 | 0.001 | 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".