An Investigation of the Extensional Viscosity of Polymer Based Fluids as a Possible Mechanism of Internal Cake Formation
Bibliographic record
Abstract
Abstract Formation of internal cake due to the invasion of reservoir rock by drilling, completion, and fracturing fluids is known to be one of the major causes of productivity reduction. Although the causes of internal cake formation are relatively well identified, the actual physical mechanisms involved in internal cake formation are yet to be understood. In particular, a quantitative means of relating physical properties of fluids to the degree of productivity reduction are not well established. A detailed investigation on the role of the rheology of viscoelastic fluids on the formation of "internal filter cakes" is, therefore, needed. The extensional viscosity for pure liquids without any structure is 3 times the shear viscosity. For these liquids, contribution of the extensional viscosity to the pressure loss is, therefore, constant and often neglected. However, for viscoelastic fluids, such as polymer based drilling and completion fluids, the extensional viscosity may be several orders of magnitude larger than the shear viscosity. This will lead to a significant increase in pressure loss, which is very often attributed to the development of internal cake. A series of core flow experiments have been conducted to investigate the possible relationship among the polymer concentration, fluid extensional viscosity, shear viscosity, filtration loss characteristics, and pressure drop across the core samples and hence, any change in the original rock permeability. Results of extensional and shear viscosity measurements, API filtration loss tests, and formation damage tests conducted by using two different Partially Hydrolized Polyacrylamide (PHPA) solutions (1.5 and 3.0 lb/bbl) are shown in this paper. Comparison of the PHPA test results with the previously published Xanthan Gum (XG) test results are also provided.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".