Bibliographic record
Abstract
Abstract Sand production and foamy oil flow are the two key factors contributing to successes in cold flow production in Alberta and Saskatchewan. However, the two mechanisms have been studied and treated separately as geomechanics and multiphase flow problems, respectively. This paper describes special experiments that were designed to combine these two processes, and conducted to study their interaction. The experiments involved flow of heavy oil with no dissolved gas (dead oil) and heavy oil with dissolved gas (live oil) in natural, intact heavy oil sand cores. It was found that gas nucleation in heavy oil is the major factor in causing the initiation of sand production in oil sand. This finding is consistent with field observations. A mathematical framework for sand production in heavy oil reservoirs was developed based on the experiments' observations. This model includes the effects of geomechanics and gas exsolution phenomena such as strength of oil sand, stress distribution in the reservoir, solution gas diffusion, foamy oil gas, and fluid phase properties. Introduction Sand production and foamy oil flow are interrelated mechanisms in primary production (cold production) of heavy oil reservoirs in Alberta and Saskatchewan. Massive sand production could cause excessive deformation in oil sands and the overburden, resulting in detrimental effects on the wells and production facilities. However, sand control measures tend to reduce the oil production rate. Numerical studies(1–4) have been conducted to predict sand production in heavy oil reservoirs. However, limited experimental work has been performed to study the sand production in oil sand. Tremblay et al.(5, 6) used a computer tomography imaging technique to examine the sand production process in sandpack columns using dead oil injected at a constant rate. They observed that a channel-like cavity was developed and evolved under a critical flow pressure gradient. However, there is no reported experimental study on sand production using natural oil sand cores and live heavy oil. The main objective of this paper is to investigate the effects of bitumen, oil sand interlocked structure, pressure gradient, and gas exsolution on the sand production near a perforation in a heavy oil reservoir. The first part of this paper describes the testing material, testing equipment, test details and results. The second part focuses on the interpretation and analysis of the test results and field observations, followed by conclusions. Details of the mathematical models used in the analysis of the test results are presented in the Appendix. Testing Material and Equipment The oil sand cores (Clearwater formation) for the experimental study presented in this paper were recovered at a depth of 424 m from an observation well (3-66-4-W4M) at a site near Cold Lake, Alberta. Core sampling was carried out using a conventional rotary core barrel of 89 mm inside diameter. Cores recovered were frozen at the site and kept inside PVC tubes in a freezer. Prior to any testing, the frozen cores were X-Rayed for sample selection. A high-pressure (70 MPa capability) stainless steel triaxial cell was used to conduct the sand production tests.
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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 | 0.001 |
| 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".