Anatomy of a parasequence: Quantitative heterogeneity analysis for reservoir modeling, Book Cliffs, Utah
- Univ. of Liverpool (United Kingdom)
The Cretaceous Blackhawk Formation (Mesaverde Group), exposed in the Book Cliffs of southeast Utah, comprises a set of clastic parasequences dominated by shoreface sand bodies. Such sand bodies form important hydrocarbon reservoirs in the Gulf Coast, the North Sea Brent Group, and other oil provinces worldwide. The 45-50 m thick Grassy Member shoreface system comprises three foreward-stepping parasequences. Individual parasequences exhibit a systematic distribution of lithofacies and major changes in vertical log profile relative to depositional dip. Parasequence stacking can result in repetition of certain facies associations in vertical sequence, particularly in the up-dip section. Parasequence bounding surfaces here are often cemented and/or intensely bioturbated and correlate down-dip with a marine flooding surface. Each facies association within a parasequence has a characteristic shale distribution that facilitates correlation of internal heterogeneities on well logs. Three-dimensional mapping of individual parasequences provides guidance for subsurface correlation at common (0.5-1.0 km) well spacings. Shales are divisible into minor flooding surfaces (fieldwide Kv barriers) and several more restricted intraparasequence types, relating to predominantly autocyclic events. Correct identification of the specific shale types in vertical sequence utilizes outcrop dip-log, gamma ray, and core analysis; i.e, data obtainable in the downhole environment. These results allow more accurate prediction of internal heterogeneity geometries and distribution in shoreface reservoir sand bodies and should provide datasets for reservoir modeling and simulation.
- OSTI ID:
- 7079200
- Report Number(s):
- CONF-910403--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 75:3; ISSN AABUD; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
CRETACEOUS PERIOD
DEPOSITION
DEVELOPED COUNTRIES
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC MODELS
GEOLOGY
MESOZOIC ERA
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NORTH AMERICA
PETROLEUM DEPOSITS
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
STRATIGRAPHY
USA
UTAH