Karst and mixing-zone porosity in the Amposta Marino field, offshore Spain

Conference · Mon Aug 01 04:00:00 EDT 1988 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:5720045

Wigley, P L; Bouvier, J D; Dawans, J M ^[1]

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1. Koninklijke/Shell Exploratie and Produktie Laboratorium, Rijswijk (Netherlands)

The offshore Amposta Marino field, located southeast of the Ebro delta, produces from the karstified Lower Cretaceous Montsia Limestone. The field is a buried-hill structure overlain by marine clastic sediments. During drowning, the buried hill was surrounded by sea water and thus represents the typical setting in which mixing-zone corrosion is a major porosity-creating process in modern carbonates (e.g., Yucatan Peninsula, Bahamas). Mixing-zone corrosion in a clastal setting differs from freshwater karstification in that it creates an essentially horizontal zone of well-connected matrix and cave porosity. This high-porosity zone is best developed on the flanks of a structure and, ideally, has a rim-like distribution. On 3-D seismic, the authors recognize a subhorizontal reflector that cuts across the gently dipping Amposta structure. This reflector was proven by seismic-to-well matching to represent a highly porous interval. Mapping of this reflector showed that it occurs somewhat discontinuously around the western margin of the structure and fairly continuously around the eastern margin, forming a clear rim feature around the flanks of the buried hill.

• OSTI ID: 5720045
• Report Number(s): CONF-8809346--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 72:8
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
DEVELOPING COUNTRIES
EUROPE
GEOLOGIC DEPOSITS
GEOPHYSICAL SURVEYS
MINERAL RESOURCES
OIL FIELDS
PETROLEUM DEPOSITS
POROSITY
RESERVOIR ROCK
RESOURCES
SEISMIC SURVEYS
SPAIN
SURVEYS
WESTERN EUROPE