Characterization and Evolution of a Carbonate Basin Floor Fan on a Leeward Side of an Isolated Carbonate Platform, Sirte Basin, Libya

Abstract

The recognition of carbonate basin floor fans and the interpretation of their formation and evolution are extremely crucial to the hydrocarbon exploration since they form important oil and gas reservoirs. There has been little research on the geometries and controlling factors of the carbonate basin floor fans from subsurface three-dimensional (3D) seismic and wireline log data. Most studies have been conducted on siliciclastic basin floor fans. Thus, this study characterizes the internal configuration and processes controlling the deposition of a lower Eocene carbonate basin floor fan system in the Sirte Basin in a sequence stratigraphic context through integrated 3D seismic and wireline log interpretations. The carbonate fan complex shows hummocky to undulated seismic geometries on vertical seismic sections and bounded by an unconformable sequence boundary at the base and a downlap surface at the top. It has an aerial extension of around 9 km from south to north along depositional dip and at least 8 km from east to west along strike. In well data, the fan system predominantly comprises limestone units intercalated with thin shale intervals. Log curves display an overall funnel-shaped trend, suggesting progradational stacking pattern. The vertical thickness of the fan complex varies from 120 to 165 m. The evolution of the carbonate fan was influenced by the interplay of accommodation space and sediment supply. A pre-existing topography, tectonic subsidence, and sea-level rise generated accommodation space for the deposition of the fan system, whereas sediment-gravity flows transported the fan sediments from the platform interior and margin to the basin floor. This study provides sedimentological and stratigraphic criteria to recognize and interpret the evolution of basin floor fans along isolated carbonate platforms from 3D seismic and wireline log data and may serve as an analog for ongoing and future studies on carbonate basin floor fans elsewhere.

Department(s)

Geosciences and Geological and Petroleum Engineering

Comments

This work was supported by National Oceanography Centre.

Keywords and Phrases

3D Seismic; Carbonate Basin Floor Fan; Eocene; Formation and Evolution; Libya; Sirte Basin

International Standard Serial Number (ISSN)

1879-1956; 1464-343X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2022 Elsevier, All rights reserved.

Publication Date

01 Dec 2022

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