Physico-Chemical Characterizationof Aphron Based Drilling Fluids
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Abstract The colloidal gas aphron (CGA) based drilling fluids are designed to minimize formation damage by blocking pores of the rock with microbubbles, which can later be removed easily when the well is open for production. Sizing CGA bubbles in accordance with the rock pore size distribution is essential for effective sealing of the pores during drilling. The physical properties (i.e. viscosity, density, fluid loss, etc.) of the CGA based drilling fluids also need to be understood in order to drill with these fluids more effectively. In this study, the physical properties of colloidal gas aphron based drilling fluids are investigated. The results of rheology, API filtration loss and density measurement testsusing various CGA based drilling fluid formulations are presented. The effects of polymer and surfactant concentration, surfactant type, shear rate, mixing time and water quality onthe CGA bubble size have been studied. Results of CGA bubble size characterization experiments are also reported. Introduction The colloidal gas aphron (CGA) based drilling fluids have recently been used for drilling at-balance in order to eliminate the problems associated with overbalanced and underbalanced drilling. In order to achieve an at-balance drilling situation, the fluid pressure must be maintained at a level greater than the formation pressure, but the difference should be kept at a minimum level to avoid invasion of the fluid into the formation1. Colloidal gas aphron drilling fluid simulates such asituation by building a bridge in front of the pores of the rock. This bridge is believed to be stabilizing the rock while allowing minimal damage to the formation. This system has been successfully implemented in high-angle and horizontal well drilling in highly depleted reservoirs2 as well as with vertical wells. Simply put, aphrons are bubbles, approximately 10 – 100 microns in diameter. The term colloidal gas aphrons was first used by Sebba3. Like regular foams, aphrons are typically composed of a gaseous (Colloidal Gas Aphrons) or liquid spherical (Polyaphron) core. Unlike foams, however, aphrons have a thin aqueous protective shell. Aphron stability is determined by the rate of mass transfer between the viscous water shell and the bulk phase. This transfer is known as the Marangoni effect3–5. If the mass transfer rate is high, aphrons will be unstable. Therefore, the shell fluid is designed to have certain viscosity to minimize the Marangoni effect. The shell is composed of an inner layer and an outer layer. Figure 1 illustrates a typical aphron. The inner layer consists of surfactant molecules which supports and separates the air core from the viscous layer. The outer layer which also supports the viscous layer is hydrophobic outwards and hydrophilic inwards. Since this bubble is in contact with the bulk water, itis believed that there is another layer in which the surfactant molecules are hydrophobic inwards and hydrophilic outwards. This indicates that there is a region in between the aphronouter shell and the bulk phase layer where a hydrophobic globule will be comfortable and, therefore, oil will adhere to the gas aphron3.
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.
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) | 0.001 | 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 it