Effect of Foaminess on the Performance of Solution Gas Drive in Heavy Oil Reservoirs
Bibliographic record
Abstract
Abstract Some of heavy oil reservoirs under solution gas drive show abnormally high final recoveries. One of the mechanisms to explain these phenomena is the foamy oil flow effect which occurs under a certain combination of capillary, viscous and gravity forces. It has been studied extensively, yet remains poorly understood and difficult to model. The objective of this work was to investigate the effect of oil foaminess on the performance of solution gas drive in heavy oil reservoirs. In this research, the first step was to find a foaming agent that will have a measurable effect on foam stability of a viscous mineral oil. An experimental procedure was developed to quantify the oil foaminess in the presence of added foaming agent. Several depletion tests were conducted with the added foaming agent at different depletion rates using a 2 meters long sand-pack. The experimental results showed that the foam stability had a positive effect on the solution gas drive performance. Such positive effects of enhanced oil foaminess were mainly observed at low depletion rates. It appears that foam stability plays an active role in the gas-phase build up during solution gas drive and the resulting production behavior. Introduction With high oil prices and continuous decline of conventional resources, the attention is shifting into heavy oil in many parts of the world. Six to nine trillion barrels, or more than two-thirds of the world's oil resources, are heavy viscous crudes that are challenging to produce.1 Heavy oil promises to play a major role in the future of oil industry. Therefore, understanding heavy oil behavior and improving the recoveries in heavy oil reservoirs is crucial to meeting the future energy demand. With higher viscosity, ranging from 500 to 50,000 cp and less than 20 ° API gravity, heavy oils are more difficult to produce than the conventional oils. The high viscosity results in lower recovery factors in primary production. However, some Canadian heavy oil reservoirs produce more than what is expected by the conventional equations. Primary recovery from these reservoirs could be as high as 20%.2 Two main effects are involved in heavy oil – solution gas drive reservoirs: geomechanical effects and fluid flow effects. In conventional solution gas drive the gas evolves in the pore space and connects with the gas in the other pores forming a free continuous gas resulting in higher gas rates. In heavy oil reservoirs, the gas bubbles tend to remain dispersed within the viscous oil because of the high viscosity, low diffusion rates and higher pressure gradients. This behavior results in higher oil reservoir. The production from this kind of reservoirs is usually accompanied with sand and is referred to as Cold Heavy Oil Production (CHOP). The two-phase flow of oil and dispersed gas bubbles is usually referred to as foamy oil flow. Smit3 appears to be the first researcher who provided an analysis to the anomalous behavior of the heavy oil reservoirs under solution gas drive using field data. The most common techniques used to produce the heavy oil from the underground formations are by using the thermal recovery 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 | 0.001 | 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".