Selective Fracturing of a Series of Perforations in a Horizontal Well Using a Resettable Straddle System
Bibliographic record
Abstract
Abstract In the Viking formation in the Redwater Operations area of Alberta, Canada, horizontal wells are typically completed using slotted liners. Earlier wells were usually completed in the vertical and subsequent fracturing of the perforated interval would generally lead to productivity improvements. In a new horizontal well drilled early in 2009 it was decided to cement casing through the productive zone and then perforate several intervals and fracture them in an attempt to improve productivity. Fracturing of horizontal sections in the past has proved problematic with the use of diverters being ineffective and cup packers being unreliable, so a new approach to allow for selective treatment of each set of perforations was researched. As a result a selective “jet pack” straddle system was chosen which allows for setting it across the zone, fracturing, unsetting the straddle, circulating the well clean and providing for the possibility of moving it further uphole to treat the next set of perforations. The well was drilled to a total vertical depth (TVD) of 650 meters (2133 ft.) and a measured depth (MD) of 1481 meters (4859ft.), with a maximum inclination of 91°. A 4-1/2” 11.6lbs/ft casing string was then cemented in place and the well perforated with six sets of perforations each one meter in length with depths ranging from 817-1467 meters (2681- 4813 ft.). A straddle system was then deployed on 2-7/8” coiled tubing with the objective of selectively fracturing each interval with some 45 metric tones (99,180 lbs) of sand at pump rates of 12-16 Bbls/min with breakdown pressures ranging from 20-30 MpA (2900-4350 psi). In this paper the authors will briefly discuss the history of the field and the evolution of the completion methods employed. They will go on to review the features of the straddle assembly and to describe in detail the selective fracturing operation which was performed in which the straddle was set and unset twelve times in six runs into the well. Productivity over the first 4 months was 50Bbls/Day, which is the longest & highest initial production rate in the field to date.
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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".