New Multiple-Interval Fracture-Stimulation Technique Without Packers
Bibliographic record
Abstract
Abstract Continuing high prices for oil and gas have increased the opportunity for producers to maximize the value of their assets. Under current market conditions, reservoirs previously considered marginal can yield an acceptable return on investment and are increasingly considered for well completion. Many lower-permeability formations require fracture stimulation during the completion phase to deliver economic rates. In the latter part of 2004, a new stimulation technique was introduced to the industry, providing well operators a method to achieve multiple-zone fracture stimulation while controlling stimulation costs. By the end of 2004, this new process had been evaluated by operators in the USA, Canada, and Australia with very positive results. This new process offers the opportunity to perforate and stimulate multiple pay zones with a single well intervention, often within 1 day. The technique employs a hydraulic jetting assembly on coiled tubing (CT) to erode perforations, after which the treating fluid is injected through the annulus between CT and casing. At the completion of the fracture stage, a small-volume slurry of high proppant concentration is placed in the wellbore to provide isolation of the just-stimulated zone from subsequent targets. This sequence (perforate, stimulate, isolate) is repeated until all desired zones have been treated. Following the final stimulation stage, the well is cleaned out with CT and turned over to production. If needed, N2 gas can be pumped through the CT to kick-off the return flow. This paper describes the operational aspects, advantages, and limitations of using this new multistage perforation and fracturing technique with example field applications. Hydrajet-Assisted Fracturing A number of options exist for completing vertical and horizontal wells that require fracture stimulation of multiple intervals in cased and cemented wellbores. Common methods of stage fracturing include straddle packer assemblies, both on jointed pipe, and, since 1997, on CT; isolating zones using mechanical, sand, and chemical plugs; and more recently, the use of hydrajet-assisted fracturing (HJF).
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".