Application of [sup 87]Sr/[sup 86]Sr, [delta][sup 18]O and [delta][sup 13]C isotopes to diagenesis correlation and connectivity of a fractured chalk reservoir, the Sidi El Kilani field, Tunisia

Conference · Mon Jan 01 00:00:00 EST 1996 · AAPG Bulletin

OSTI ID:6862394

Mearns, E W; McBride, J J ^[1]; Bramwell, M

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1. Isotopic Analytical Services Limited., Aberdeen (United Kingdom)

Oil is produced primarily from open fracture porosity in Upper Cretaceous chalk in the Sidi El Kilani oil field. Strontium Stratigraphy analyses of primary, unaltered matrix chalk has confirmed a Campanian to Maastrichtian age and has allowed dating of the reservoir with a resolution of [+-]1 Ma. This has facilitated reservoir correlation and has indicated where section is missing in certain wells due to faulting. [sup 87]Sr/[sup 86]Sr, [delta][sup 18]O and [delta][sup 13]C analyses suggest an early generation of fracture fill calcite cement may have formed by redistribution of CaCO[sub 3] from underlying carbonate sequences at temperatures in the region 35-55[degrees]C. Calcite cemented fractures tend to be healed and are not productive. Strontium Isotope Residual Salt Analyses (SrRSA) conducted on core, provide information on the formation water chemistry and reservoir connectivity at the time of oil filling. These data suggest that the NW-SE trending fault system that bisects the field is sealed across much of the fault plane. The main oil pool lies SW of the fault. A later generation of dolomite and barite cements, associated with productive open fractures, have Sr-O-C composition consistent with precipitation from fluids circulating at the time of hydrocarbon charge at temperatures close to current reservoir conditions of 70-75[degrees]C. Predicting the distribution of dolomite cemented open fractures has thus helped guide the development strategy of the field.

• OSTI ID: 6862394
• Report Number(s): CONF-960527-; CODEN: AABUD2
• Journal Information: AAPG Bulletin, Vol. 5; Conference: Annual convention of the American Association of Petroleum Geologists, Inc. and the Society for Sedimentary Geology: global exploration and geotechnology, San Diego, CA (United States), 19-22 May 1996; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
PETROLEUM
PRODUCTION
RESERVOIR ROCK
DIAGENESIS
RESOURCE POTENTIAL
TUNISIA
OIL FIELDS
STRATIGRAPHY
AFRICA
DEVELOPING COUNTRIES
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOLOGIC DEPOSITS
GEOLOGY
MINERAL RESOURCES
PETROLEUM DEPOSITS
RESOURCES
020200* - Petroleum- Reserves
Geology
& Exploration