Developing a Stage Tool for Cemented Back Monobore Completions with Open Hole Multi-Stage Systems in the Montney
Bibliographic record
Abstract
Abstract Challenges associated with cementing horizontal wellbores, as well as the higher operational time and costs associated with the cemented liner, plug and perf method, has resulted in many operators switching to open hole multi-stage system (OHMS) completions. In addition, production increases have been realized with OHMS due to access to the entire open hole lateral. To further optimize economics, cemented back monobore completions with OHMS are becoming the completion method of choice for operators. This is because they save on wellbore costs by eliminating the intermediate casing. Instead, the build section of the wellbore is cemented back to surface using a stage tool once the liner is installed. In addition, the cemented back method allows for OHMS systems to be run in on liner eliminating the need to trip out the running string and trip in the frac string. This paper outlines the operational procedure for cemented back monobore OHMS completions. Due to various issues with conventional plug-type cementing stage tools a new hydraulically activated, mechanically closed cementing stage collar was designed to open/close without the use of a plug/dart. The new stage tool addresses the operational issues encountered with conventional tools and further reduces costs by reducing rig time. With the new stage collar, there is no drill out of plugs and cement after the cementing operation, eliminating debris that could be problematic for the OHMS functioning. The development of the new stage collar through lab testing and field trials is discussed. This technology has been successfully used in various formations in Canada and the United States. This paper presents case study examples of installations in the Montney formation. Introduction Geology of the Montney. The Montney formation covers an area of approximately 246,000 km2 (95,000 sq. mi.) stretching across Alberta and British Columbia (Figure 1). It is a leading example of an unconventional gas play in the Western Canadian Sedimentary Basin containing vast quantities of proven gas reserves. Estimates of gas in place are up to 700 Tcf. The Montney consists of four distinct intervals: the Upper, Middle, Middle Lower and Lower (National Energy Board, Canada). Characterized by its low permeability (0.01 - 0.5 mD) and thick stack, the Montney is a prime candidate for horizontal drilling and hydraulic fracturing techniques. The formation is a blend of sandstone, siltstone and shale intervals with porosity up to 8% and true vertical depth to 3,950 m (13,000 ft).
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".