Bibliographic record
Abstract
Abstract The CHOPS process involves the growth of high permeability channels (wormholes) into the reservoir. The wormholes provide improved access to the reservoir, thereby substantially increasing oil production rates. Field evidence and laboratory experiments indicate that wormholes tend to persist as stable high-permeability flow channels throughout the duration of the CHOPS process. The existence of wormholes in the reservoir needs to be taken into consideration in the design of post CHOPS recovery processes. One of the key issues is the stability of wormholes during the re-pressurization phase of any follow up process to CHOPS. For example, wormholes could remain as stable high permeability flow channels to deliver injected fluids into a reservoir or they could collapse to improve conformance for fluid injection. This paper presents the results of experiments testing the stability of wormholes under conditions that could be destabilizing such as cold and hot water circulation, heating, and pressurization with hydrocarbon gases (e.g., methane, ethane). The experiments were performed in a triaxial cell, approximately 19 cm in diameter and 18 cm long, packed with water-wet sand and saturated with heavy oil. Wormholes were generated in the pack by injecting heavy (dead) oil into the cell at a sufficiently high rate to produce sand from the pack. Then, conditions that could be destabilizing to wormholes were applied to test their outcome. Cold water flowing through the wormhole eroded its walls, eventually causing the pack to collapse after more than a week. The injection of hot water accelerated the process of erosion considerably. Heating the pack did not cause it to collapse, but the wall of the wormhole was destabilized to a limited extent in that the diameter of the wormhole increased by more than a factor of two. The heating reduced the viscosity of the heavy oil in the pack, causing the apparent strength of the sand to decrease. Pressurizing the sand pack with methane and then slowly depressurizing it did not destabilize the wormhole. However, pressurizing the pack with ethane caused the sand matrix surrounding the wormhole to collapse over a period of two weeks. As in the case of heating, dissolution of ethane into the heavy oil caused the apparent strength of the sand to decrease by reducing the viscosity of the heavy oil in the pack. Although the confining pressure in these experiments was relatively low, the experimental cell did not allow for stress redistribution due to the deformation of the sand matrix, as would occur in the field. For this reason, the wormholes generated in the experiments were less stable than ones in the field. Consequently, the laboratory conditions that resulted in wormhole collapse should be regarded as a guide to the behaviour that would be expected in the field.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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) | 0.002 | 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 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".