Laboratory Study of Sand Production in Unconsolidated Reservoir
Bibliographic record
Abstract
Abstract Sand production is a major operational and economical concern in the oil industry due to the potential risk of well failure, limited productivity, erosion of facilities, and increased operating expense. Experimental studies play an important role in understanding the behavior of sand production under different conditions. However, the existing traditional sand production experiments such as thick-walled, cylinder approach or perforation collapse test are only able to predict the onset of sanding and cannot be used to analyze sand production performance over time. In this work, preliminary empirical sanding prediction was performed based on well log data and the formation mechanical properties. The steady-state core flooding tests and core swelling tests were applied to simulate and investigate how the volumetric sand production changes with different flow rates, water saturations and the salinity of injected water. The cores and crude oil samples from an unconsolidated sandstone reservoir in China were used in the tests. The sand flow rate, accumulative sand volume and relative permeability were measured during the sand production process. The experimental results indicated that the sand production rose at the beginning and declined with the increase of flow rate. During the early water-free production stage, the skeleton sand was not destroyed under realistic reservoir/well flow conditions so that the oil production with sanding was preferred. However, as water saturations increased from 20% to 80%, the permeability decreased by 80% accompanied by dramatic increase in sand production. This is due to the high content of Kaolinite, Illite and Montmorillonite with weak cement in the core which swells significantly and blocks the porosity once it is subjected to the water influx. Therefore, sand control should be considered when water saturation is over 20%. The change of sand production rate demonstrated that both the transient and continuous sand production could be involved in this reservoir. In addition, it is expected that the lower salinity of injected water aggravates the sand production.
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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) | 0.000 | 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".