Novel Controlled Pressure Coring and Laboratory Methodologies Enable Quantitative Determination of Resource-in-Place and PVT Behavior of the Duvernay Shale
Bibliographic record
Abstract
Abstract The North American hydrocarbon supply market has been transformed by recent discoveries in regionally continuous reservoir units consisting of shale and tight sands. Effective porosity values in these reservoirs average as low as 2% to 6% with nanoDarcy permeability in situ. Classical means of determining resource-in-place values in these unconventional formations involves integrating core and log analysis methodologies, where numerous levels of uncertainty exist. Controlled pressure coring operations were conducted on a sequence of wells drilled into various maturity windows in the rapidly emerging liquids-rich Duvernay Shale through the course of 2011 and 2012. Capturing critical resource-in-place parameters and conducting quantitative analysis of volatile hydrocarbons contained within the cored interval required the development of new field and laboratory methodologies. These procedures represent the only currently available workflow capable of directly capturing and analyzing reservoir hydrocarbons from core material. Field operations and core preservation steps were developed to maintain the integrity of the hydrocarbon system during shipping and core processing. Additionally, a laboratory methodology was developed for preserving and extracting liquid hydrocarbons from core material. By quantitatively recombining these extracted fluids with volatile hydrocarbons captured from the controlled pressure coring operation, in situ PVT behavior of this single-phase volatile oil/condensate reservoir can be determined. As a result, recombined fluids can be compared to production samples for the purpose of studing pore scale mechanisms affecting production. Key breakthroughs were made during all stages of the workflow, and it was determined that core capture and surface handling operations are just as important as developing the new laboratory techniques required to understand resource uncertainty, effective fluid mobility, and PVT behavior. This paper describes and documents the key advancements made in coring operations and specialized core analysis, as well as their role in accurate quantification of hydrocarbons in place and the determination of in situ PVT behavior of the Duvernay Shale.
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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 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".