Investigation of the Relationship between Rock Mechanical Parameters and Wellbore Stability in Depleted Wells
Bibliographic record
Abstract
The depletion of oil and gas reserves has compelled drilling companies to carry out drilling operations in mature oilfields. However, drilling in brownfield areas can pose various hazards, such as loss circulation and wellbore collapse, due to the decline in reservoir pore pressure. This research focuses on analyzing the stability of wellbores in directional wells within depleted reservoirs, with the aim of enhancing wellbore integrity during drilling operations. Experimental tests were first of all conducted to examine the impact of pore pressure depletion on mechanical parameters of the rock formation, including compression strength, Young's modulus, and Poisson's ratio. Then, analytical equations of matrices transformation were employed to convert the in-situ stress from the in-situ coordinate system to the wellbore coordinate system. Subsequently, the collapse and fracture gradients of the wellbore were evaluated under different pore pressure conditions using the Mohr-Coulomb shear and tensile failure criteria. The results indicated that the strength of the formation after pressure decline is a significant factor contributing to the reduction of the mud density window. With pore pressure depletion, the safe mud window became narrower. For an inclination angle of 90, the initial mud window in the direction of the minimum horizontal stress decreased by 52.80% after reservoir depletion, while it decreased by 85.78% in the direction of the maximal horizontal stress.
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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 | 0.000 | 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) | 0.000 | 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".