Seismic facies and attribute analyses of a prograding clinoform complex, northeast Sirt Basin, Libya
DOI:
https://doi.org/10.37376/ljst.v14i2.7207Keywords:
Seismic facies, carbonate slope, seismic attributes, clinoforms, Sirt Basin, LibyaAbstract
The internal geometry and depositional system of a prograding clinoform complex are investigated using integrated 3-D seismic and wireline log data from the Assamoud Field in NE Sirt Basin, Libya, through detailed seismic facies and attribute analyses. Seismic attributes have proved to be a highly effective method for the interpretation of carbonate facies. Six major seismic facies (SF) show complex lithology and depositional systems. SF1 consists of high angle, sigmoidal, continuous reflections of high amplitude clinoforms. SF2 has high angle oblique paralleland semi-continuous reflections of moderate to high amplitude clinoforms. The prograding nature of SF1 and SF2 suggest carbonate progradation into the interplatform basin through downslope shedding from the platform top and margin. SF3 consists of subparallel and semi-continuous reflections of moderate amplitude located basinward of the clinoformin SF1 and SF2. SF4 shows undulated or hummocky internal configuration andis discontinuous to semi-continuous of moderate amplitude reflections and was interpreted as a basin floor fan deposited on the lower slope or basin during sea-level lowstand. SF5 displaysan erosive channel-shaped geomtery and wavy to subparallel semi continuous reflections of moderate to high amplitude. It was interpreted as an incised valley developed on top of the clinoforms. SF6 displays broken reflections and circular features along the upper sequence boundary which are interpreted as karst features developed as a result of subaerial exposure and erosion of the upper sequence boundary. The seismic facies and attribute analysis, log facies and their stacking patterns, and the position of the facies along the platform enabled the subdivision of the clinoform complex into two different subsystems: proximal slope that contains SF1 and SF2 and consist predominantly of thick successions of limestone with a minor amount of mud, and a distal slope that contains SF3 and is comprised of thick limestone successions with more shale units compared to the proximal slope. The prograding clinoforms may have formed as a result of sea-level highstands when sediment supply outpaces the rate of creation of accommodation space. The truncational termination patterns on top of the clinoforms suggest major erosion and removal of the upper portion of the clinoforms.
Downloads
References
Abadi, A.M., Van Wees, J.D., Van Dijk, P.M. and Cloetingh, S.A. (2008) ‘Tectonics and subsidence evolution of the Sirt Basin, Libya’, AAPG bulletin, 92(8), pp. 993-1027.
Abdalla, M.A, (2021a) ‘Seismic attributes aided detection of NW-SE trending faults developed on an isolated carbonate platform in the NW Sirte Basin, north central LIBYA’, International Journal of Engineering Applied Sciences and Technology, 5, 53, pp.
Abdalla, M. and Yang, W. (2021) ‘Progradation of a middle Eocene carbonate slope system, Assamoud Field, Sirte Basin, north central Libya–Implications on the dynamics of lateral growth of isolated carbonate platforms’, Marine and Petroleum Geology, 129, p.105119.
Abdalla, M.A, (2021b) ‘Seismic Attributes Aided Characterization of Margin Backstepping and Advance along Isolated Carbonate Sequences, Sirt Basin, Libya’, Al-Mukhtar Journal of Sciences, 36(4), pp. 280-287.
Adams, E. W., Schlager, W., (2000) ‘Basic type of Carbonate Platform to Basin Transitions on Seismic Data and in Outcrops 245 submarine slope curvature’, Journal of Sedimentary Research, 70, pp. 814–828.
Ambrose, G. (2000) ‘The geology and hydrocarbon habitat of the Sarir Sandstone, SE Sirte Basin’, Libya. Journal of Petroleum Geology, 23(2), pp. 165-192.
Baird, W. D., Aburawi R. M., Bailey J. N. (1996) ‘Geohistory and petroleum in the central Sirte Basin, in Salem M. J., Busrewil M. T., Misallati A. A., Sola M. A., eds., The geology of the Sirte Basin: Amsterdam, Elsevier’, 3, pp. 3–56.
Barr, F. T., Weegar, A. A. (1972) Stratigraphic Nomenclature of the Sirte Basin, Libya. Petroleum Exploration Society of Libya, p. 1-179).
Brown, A. R., (2004) Interpretation of 3-D seismic data (6th Ed.) AmericanAssociation of Petroleum Geology Memoir, pp. 42, 54.
Cook, H. E., & Mullins, H. T., (1983) Basin margin environment, in P. A. Scholle, D. G. Bebout, and C. H. Moore, eds., Carbonate depositional environments: AAPG Memoir 33, pp. 540–617.
Eberli, G. P., Anselmetti, F. S., Betzler, C., Van Konijnenburg, J. H., & Bernoulli, D. (2004) Carbonate platform to basin transitions on seismic data and in outcrops: Great Bahama Bank and the Maiella platform margin, Italy.
Emery, D. and Myers, K. J. (1996) Sequence Stratigraphy. Victoria, Australia: Blackwell Science Ltd., p. 291.
Gras, R., Thusu, B. (1998) ‘Trap architecture of the early Cretaceous Sarir Sandstone in the eastern Sirte Basin, Libya’, Geological Society, London, Special Publications, 132(1), pp. 317-334.
Guiraud, R., Bosworth, W. (1997) ‘Senonian basin inversion and rejuvenation of rifting in Africa and Arabia: synthesis and implications to plate-scale tectonics’, Tectonophysics, 282(1-4), pp. 39-82.
Hallett, D., Clark-Lowes, D. (2017) Petroleum geology of Libya. Elsevier, (https://shop.elsevier.com/books/petroleum-geology-of-libya/hallett/978-0-444-63517-4)
Hart, B. S., (2012) Introduction to Seismic Interpretation. American Association of Petroleum Geology Discovery Series No. 16 (electronic book).
Hine, A.C., Locker, S.D., Tedesco, L.P., Mullins, H.T., Hallock, P., Belknap, D.F., Gonzales, J.L., Neumann, A.C. and Snyder, S.W. (1992) ‘Megabreccia shedding from modern, low-relief carbonate platforms, Nicaraguan Rise’, Geological Society of America Bulletin, 104(8), pp. 928-943.
Kenter, J. A. M., (1990) ‘Carbonate platform flanks: Slope angle and sediment fabric’, Sedimentology, 37, pp. 777–794.
Koson, S., Chenrai, P. and Choowong, M. (2013) ‘Seismic attributes and their applications in seismic geomorphology’, Bulletin of Earth Sciences of Thailand, 6(1), pp. 1-9.
Lemnifi, A. A., Liu, K. H., Gao, S. S., Reed, C. A., Elsheikh, A. A., Yu, Y., Elmelade, A. A. (2015) ‘Azimuthal anisotropy beneath north central Africa from shear wave splitting analyses’, Geochemistry, Geophysics, Geosystems, 16, pp. 1105–1114. https://doi.org/10.1002/2014GC005706.
Lemnifi, A., Elshaafi, A., Browning, J., El Ebadi, S., Gudmundsson, A. (2017a) ‘Crustal thickness beneath Libya and the origin of partial melt beneath AS Sawda Volcanic Province from receiver-function constraints’, J. Geophys. Res. Solid Earth. https://doi.org/10.1002/2017JB014291
Macurda Jr, D. B. (1997) ‘Carbonate seismic facies analysis Carbonate seismology’, Society of Exploration Geophysicists Geophysical Developments Series, 6, pp. 95-119.
Mitchum J.r., R.M., Vail, P.R., Thompson III, S., (1977) Seismic stratigraphy and global changes of sea level; Part 2, the depositional sequence as a basic unit for stratigraphic analysis. In: Payton, C.E. (Ed.), Seismic Stratigraphy; Applications to Hydrocarbon Exploration, vol. 26. American Association of Petroleum Geologists Memoir, pp. 53-62.
Mouzughi, A. J. and Taleb, T. M. (1981) Tectonic elements of Libya, 1:2,000,000. National Oil Corporation, Libya.
Roohi, M., (1996) Geological view of source-reservoir relationships in the western Sirte Basin. In: Salem, M.J., El-Hawat, A.S. and Sbeta, A.M., (eds), The Geology of the Sirte Basin, volume II. Elsevier, Amsterdam, p. 323-336.
Sheriff, R. E., (2002) Encyclopedic Dictionary of Applied Geophysics (4th ed.), Society of Exploration Geophysicists, p. 429.
Van der Meer, F. D., CLOETHING, S. (1993) ‘Late Cretaceous and Tertiary subsidence history of the Sirte Basin (Libya); an example of the use of backstripping analysis’, ITC journal, (1), pp. 68-76.
Wenneker, J.H.N., Wallace, K.F., Abugares, I.Y., (1996) The geology and hydrocarbons of the Sirte Basin: a synopsis. In: Salem, M.J., Mouzoughi, A.J., Hammuda, O.S. (Eds.), the Geology of the Sirte Basin, vol. 1. Elsevier, Amsterdam, pp. 3-56.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2025 Libyan Journal of Science &Technology
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
