Influence of Confining Stress in Petrophysical Properties Changes during Thermal Recovery in Silty Sands Colombia
Bibliographic record
Abstract
Abstract Thermal recovery processes in heavy oil reservoirs have become an efficient technique for the exploitation of the viscous oil that is trapped in the porous space. The heat reduces the oil viscosity and thus allows it to flow from the formation to the well. In recent years, there have been technological advances that have permitted such operations to become safe and profitable. Having a right understanding of what happens to the reservoir and the surrounding formations during thermal recovery has become a topic of interest to reduce the environmental impact of these operations and to generate models that predict production and recovery factor accurately and reliably. Understanding the geomechanical behavior of this type of formations under different scenarios of stress and temperature is essential to model this kind of operations due to possible scenarios during thermal recovery. Confining condiciton is related to the depth of the reservoir and tectonic activity in the area. Heavy oil reservoirs are mainly located at detph less than 3000 feet according to Shafiei et. al (2013) [1]. This usually makes the reservoir formations to be unconsolidated or poorly consolidated, this kind of formations show elastoplastic behavior where stress-strain relationship plays an essential role in the production/injection process. Samples from an outcrop of an oilsand formation located in Eastern Cordillera of Colombia were collected to performe triaxial tests at high temperature conditions. Picacho formation presents a high content of fines as other important heavy oil formations in Colombia, where thermal recovery has been considered. Fines content is crucial in the understanding of the material behavior due to particular silt and clay behavior such as thermal consolidation and mineralogic change caused by the temperature increment. During heating, different parameters were measured in order to understand what occurs to the porous medium while it is subjected to changes of temperature. The measurements include pore volume, total volume and permeability at different stages during the heating process. The experiments were perfomed at different conditions of effective confining stress (mainting pore pressure constant). The results show a significant dependence of the petophysical properties such us permeability and porosity to the confining stress at which the porous medium is subjected.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".