Breaking Up Is Hard To Do: Creating Hydraulic-Fracture Complexity in the Bakken
Bibliographic record
Abstract
This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 163827, ’Breaking Up Is Hard To Do: Creating Hydraulic-Fracture Complexity in the Bakken Central Basin,’ by C. Mark Pearson, SPE, Larry Griffin, SPE, and Chris Wright, Liberty Resources, and Leen Weijers, SPE, Liberty Oilfield Services, prepared for the 2013 SPE Hydraulic Fracturing Technology Conference, The Woodlands, Texas, 4-6 February. The paper has not been peer reviewed. Drilling the Bakken in North Dakota has increased dramatically over the past several years as operators sought to hold acreage and create value with the drill bit. Much of this activity has been in the central-basin portion of the Williston basin where wells drilled before 2008 were uneconomic. Advances in completion technology caused a fundamental shift in economics, and the whole central-basin area, greater than 2,500 sq miles, has approximately 100 rigs drilling. The greatest change in completion design was incorporating high-intensity multistage fracturing. The Bakken completion design is different from other shale-gas developments, with the widespread use of uncemented liners with external packers in the openhole lateral to create the multistage zonal isolation. Introduction The Bakken formation (highlighted in red in Fig. 1) is part of the Williston basin, which spans southern Saskatchewan and Manitoba in Canada into North Dakota and Montana in the United States. The basin was formed as a subtle down- warping between the Superior craton to the northeast and the Wyoming craton to the southwest. The Williston basin is a gently dipping basin with very little structural deformation, except for a few structural features including the Nesson anticline and the Cedar Creek anticline, shown in Fig. 1. The Upper and Lower Bakken shales are prolific source rocks for the petroleum system. The middle member consists of five to seven distinct lithofacies that range from silty sandstone on the east flank of the basin to silty dolomite on the west flank. Porosities in the middle member range from 4 to 10%, and permeabilities generally are less than 0.1 md. Development History The first Bakken-formation well came on production in 1953, 2 years after first oil production in North Dakota. Over the next 15 years, a total of 42 vertical wells were completed in the Middle Bakken or Three Forks formations. Commercial production required the existence of natural fractures associated with the uplift and could be correlated to the second- derivative curvature in the formation.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".