Explaining production - a review of unexpected production during the initial appraisal of a organic rich shale play by integrating geology and petrophysics with production. Woodford shale, USA.
Bibliographic record
Abstract
This paper presents a review of the integration of geologic and petrophysical interpretation explaining unpredicted production results. It was found that a subzone of the reservoir that had been labeled as a non-significant contributor to production is likely he dominate contributor. The Woodford shale play in the US Anadarko Basin has been a prolific producer yielding mean EUR's of approximately 450 MBO in non-core regions. The core of the Woodford has been well developed with the gas rich 'Cana Field' in Canadian County, Oklahoma. Recently exploration of the oil rich-updip extent of the resource has found highly prospective, oil rich results. Despite having a petrophysical model calibrated to core in the play; production results have not met initial assessments of calculated oil in place after a total of 28 horizontal wells have been brought online. There was no significant trend between OOIP estimates and production. In this study Production results (initial 30 day average) were compared to petrophysical properties, stratigraphic thickness, facies variation, and lateral placement. The Woodford and overlaying Osage Limestone formation were analyzed as isolated and comingled flow unit. The distinctive Woodford 'Chert' interval was also isolated and used for evaluation. Initial geologic work gave a misleading concept that Osage Thickness contributed to stronger production. This was found to be immaterial. The strongest correlation found was the relationship between the Woodford Chert interval's OOIP and production (r =0.81). There was no notable correlation (r = 0.20) between the non-Chert Woodford OOIP volume to production. A general trend between maturities was also identified; slightly immature wells resulted in unpredictable results. This was very significant for the characterization of the Woodford Reservoir. Previous landing targets kept our drilling window away from the Woodford Chert zone. Future appraisal efforts and better understanding of the Woodford should account focus on characterization of the Chert zone. Additionally, more efforts should be made to understand the optimal completion design for the zone.
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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 | 0.003 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.008 | 0.009 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.004 | 0.004 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| 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".