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Record W2185359536

LIMESTONE FACIES AND STRATIGRAPHIC TRAPS

2006· article· en· W2185359536 on OpenAlexaboutno aff
Ralph W. Edie

Bibliographic record

Venuenot available
Typearticle
Languageen
FieldEngineering
TopicHydrocarbon exploration and reservoir analysis
Canadian institutionsnot available
Fundersnot available
KeywordsGeologyAnhydriteFaciesShoalLithologyDrillingPetroleum reservoirGeochemistryStructural basinPetroleumUnconformityPaleontologyDolomitizationGeomorphology
DOInot available

Abstract

fetched live from OpenAlex

The texture and faunal content of bedded limestones may be used to outline various environments of deposition including those of shelf (shoal, inter-shoal and lagoon) and basin areas. Shoal deposits, represented in general by well sorted calcarenites of both bioclastic and precipitated origin, are commonly the most porous and permeable limestone types. Thus, where petroleum accumulation in bedded limestone units is limited at least in part by primary up-dip or lateral permeability variations, facies maps showing the probable distribution of permeable shoal areas are extremely valuable in outlining petroleum prospects. Such prospects include both field extensions (most critical during early development drilling) and prospects in strictly wildcat areas. In most cases, drilling locations to test the stratigraphic anomaly may be given without further geological or geophysical work. This method of exploration is extremely cheap and its -effectiveness is limited only by the quality of the lithologic data available and the environmental interpretation. An example of the application of lithofacies and biofacies techniques1 to petroleum exploration is shown by recent studies along the Mississippian Midale trend is southeastern Saskatchewan. Fields along this trend form part of a huge regional stratigraphic trap formed largely by truncation and sealing of the Midale members* of the Charles formation. The seal is formed by secondary anhydrite infilling pores at the truncated erosion surface and overlying impermeable red beds. Also important to entrapment is the presence of a locally, developed primary anhydrite bed beneath the pay zone. This anhydrite unit forms a floor to the reservoir and prevents oil from migrating updip along the unconformity. Regionally, oil accumulations along the Middle trend are limited by erosional truncation of the Midale member in an up-dip direction and occurrence of water down-dip. In detail, however, productive fields along the trend are limited by lateral and locally by up-dip decrease in permeability. The permeability variations are directly related to primary sedimentation patterns. Thus, detailed facies maps of the Midale member show the close relationship between productive areas and permeable limestone (shoal) facies. These maps are presently being used to outline drillable petroleum prospects.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.001
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.023
Threshold uncertainty score0.076

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.001
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0040.003
Science and technology studies0.0000.000
Scholarly communication0.0010.000
Open science0.0010.001
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0230.006

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.

Opus teacher head0.005
GPT teacher head0.175
Teacher spread0.170 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

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".

Quick stats

Citations0
Published2006
Admission routes1
Has abstractyes

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