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Seismic Characterization of the First 3D Surveys Offshore Cyprus and Lebanon*
Øystein Lie1 and Mark Trayfoot1
Search and Discovery Article #10194 (2009)
Posted May 22, 2009
*Adapted from oral presentation at AAPG International Conference and Exhibition, Cape Town, South Africa, October 26-29, 2008
1Petroleum Geo-Services, Oslo, Norway (mailto:[email protected] )
The
first 3D seismic data in the deep water offshore Cyprus and Lebanon have been
acquired, processed and interpreted. Pre-stack time migration was applied and
the 3D data sets have high signal to noise-ratio and very high reflectivity at
both shallow and deep levels. Despite the lack of exploration well
data, a
consistent chronostratigraphic framework has been built across Cyprus and
Lebanon and implications for prospectivity assessed. Several petroleum systems
were identified, and potential prospect
types
include four-way dip closure
structures and stratigraphic traps. Direct hydrocarbon indicators, including
amplitude and frequency anomalies, are associated with many of the identified
prospects. Amplitude maps have been extracted on offset stacks, and a good
correlation between amplitude anomalies and the closures was found. The recent
3D seismic is considered to reduce the exploration risk in this unexplored
frontier area.
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The offshore areas of Cyprus and Lebanon in the eastern Mediterranean Sea are currently unexplored with respect to hydrocarbon resources. The first 3D seismic surveys were acquired to obtain an improved understanding of the geological structures and the petroleum potential in these frontier deep water areas. The regional tectono-stratigraphic framework of the area is influenced by the relative movements of three adjacent continental tectonic plates; the African plate to the south, the Arabian plate to the east, and the Anatolian sub-plate to the north. The Levantine Basin, containing up to 10km of Mesozoic-Cenozoic sediments, is situated on the northeast edge of the African plate. The basin is bounded to the north by the Latakia Ridge (LR), part of the Cyprus deformation zone (Hall et al., 2005), to the west by the Eratosthenes Seamount (ES) and to the south by the Nile Delta Cone (NDC) (Figure 1).
Two areas considered highly prospective were selected for acquisition of the 3D seismic data. The surveys were acquired late 2006/early 2007 and cover approximately 1550km² (Phase 1 to the south) and 1350km² (Phase 2 to the north) (Figure 1). Phase 1 covers the central part of the Levantine Basin. Phase 2 covers the northern part of the basin, the Latakia Ridge, and several other large Syrian- and Cyprus-Arc deformation folds. The pre-stack time migrated 3D seismic data sets have a high signal to noise-ratio and a very high reflectivity at both shallow and deeper levels. Although no exploration wells have yet been drilled offshore Cyprus and Lebanon, valuable information can be extracted from some excellent geological exposures and data from seven Lebanese onshore exploration wells (Walley, 1998). Analogues can also be drawn from the proven hydrocarbon producing provinces of the Nile Delta, North Sinai, Gaza and Israel.
Seismic Interpretation and Hydrocarbon Plays
Nine key regional horizons have been interpreted to evaluate the prospectivity of the area. By tying the key reflectors from Cyprus in the west to Lebanon in the east a consistent chronostratigraphy was established. The following horizons were interpreted; Seabed, Intra Pliocene, Base Pliocene, Base Messinian Evaporite, Upper Miocene, Mid Miocene, Base Miocene, Eocene Unconformity and Senonian Unconformity (Figure 2).
The area contains a number
of potential hydrocarbon plays and a variety of structural and stratigraphic
trapping styles exist. The Upper Miocene Messinian Evaporite Formation which
forms a regional cap rock in the eastern Mediterranean Sea is
Prospect
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