Cyclic transgressive and regressive sequences, Paleocene Suite, Sirte basin, Libya

Conference · Thu May 01 00:00:00 EDT 1986 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:5301325

Abushagur, S A

The Farrud lithofacies represent the main reservoir rock of the Ghani oil field and Western Concession Eleven of the Sirte basin, Libya. Eight microfacies are recognized in the Farrud lithofacies in the Ghani field area: (1) bryozoan-bioclastic (shallow, warm, normal marine shelf deposits); (2) micrite (suggesting quiet, low-energy conditions such as may have existed in a well-protected lagoon); (3) dasycladacean (very shallow, normal marine environment); (4) bioclastic (very shallow, normal marine environment with moderate to vigorous energy); (5) mgal (very shallow, normal marine environment in a shelf lagoon); (6) pelletal-skeletal (deposition within slightly agitated waters of a sheltered lagoon with restricted circulation); (7) dolomicrite (fenestrate structures indicating a high intertidal environment of deposition); and (8) anhydrite (supratidal environment). The Paleocene suite of the Farrud lithofacies generally shows a prograding, regressive sequence of three facies: (1) supratidal facies, characterized by nonfossiliferous anhydrite, dolomite, and dolomitic pelletal carbonate mudstone; (2) intertidal to very shallow subtidal facies, characterized by fossiliferous, pelletal, carbonate mudstone and skeletal calcarenite; and (3) subtidal facies, characterized by a skeletal, pelletal, carbonate mudstone. Source rocks were primarily organic-rich shales overlying the Farrud reservoir rock. Porosity and permeability were developed in part by such processes as dolomitization, leaching, and fracturing in the two progradational, regressive carbonate facies. Hydrocarbons were trapped by a supratidal, anhydrite cap rock.

• Research Organization: Univ. of Texas, El Paso
• OSTI ID: 5301325
• Report Number(s): CONF-860624-
• Journal Information: Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 70:5; Conference: American Association of Petroleum Geologists annual meeting, Atlanta, GA, USA, 15 Jun 1986
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
LIBYA
OIL FIELDS
SEDIMENTARY BASINS
RESERVOIR ROCK
SOURCE ROCKS
STRATIGRAPHY
DEPOSITION
GEOLOGIC HISTORY
GEOLOGIC TRAPS
PERMEABILITY
POROSITY
SHALES
TERTIARY PERIOD
AFRICA
CENOZOIC ERA
DEVELOPING COUNTRIES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOLOGY
MINERAL RESOURCES
PETROLEUM DEPOSITS
RESOURCES
ROCKS
SEDIMENTARY ROCKS
020200* - Petroleum- Reserves
Geology
& Exploration