Determining sand-body geometries for waterflood reservoirs: Examples from Oklahoma
- Mobil Research and Development Corp., Dallas, TX (USA)
Waterflood projects require an accurate knowledge of reservoir geometry and well-to-well continuity. However, sandstones with thin, multiple-pay zones can be extremely difficult to correlate with confidence. Two case studies of Pennsylvanian sandstones in Oklahoma illustrate how a model for the depositional history of such reservoirs can be an effective tool for determining reservoir continuity. In contrast, correlation criteria such as similar wireline log signatures and relative sand-body thicknesses are not reliable in many situations. In Southwest Logan field (Beaver County), 5 to 15-ft thick reservoir sands formed as shallow marine sand ridges. Their dimensions were approximated from height-to-width ratios of modern sand ridges. Then the reservoir sands were mapped using wireline logs and core data. Individual reservoir sands were approximately 1-2 km wide and stacked en echelon vertically. Thus, a line-drive waterflood pattern oriented parallel to the axes of the ridges is recommended. Tatums field (Carter County) consists of 5 to 50-ft thick sandstones deposited in various deltaic environments. Distributary channel sands have good continuity downdip, but are narrow and lenticular across depositional strike. Crevasse splay and other bay-fill sands were deposited marginal to the channels and are extremely discontinuous. This depositional model can be used to improve flood patterns for these sands, leading to improved sweep efficiency. In both examples, for effective mapping, the depositional facies models have been used to register reservoir quality and wireline log signatures.
- OSTI ID:
- 5337919
- Report Number(s):
- CONF-8703189--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (USA), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Vol. 71:2; ISSN 0149-1423; ISSN AABUD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020300* -- Petroleum-- Drilling & Production
DEPOSITION
ENERGY SOURCES
ENHANCED RECOVERY
FEDERAL REGION VI
FLUID INJECTION
FOSSIL FUELS
FUELS
GEOLOGIC DEPOSITS
GEOLOGIC MODELS
MINERAL RESOURCES
NORTH AMERICA
OIL WELLS
OKLAHOMA
PETROLEUM
PETROLEUM DEPOSITS
RECOVERY
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SWEEP EFFICIENCY
USA
WATERFLOODING
WELL LOGGING
WELLS