Technical Library

  • Lebanon – The Next Frontier in the Eastern Mediterranean

    Author: Matthew Pyett
    EAGE - 3 June 2019

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    Located in the easternmost part of the Mediterranean Sea, offshore Lebanon remains a frontier, untested basin surrounded by many discoveries and proven working petroleum systems. Large gas fields have been discovered in clastic reservoirs within the southern portion of the Levantine Basin, these sediments are derived from the Nile Delta cone to the south, proving the existence of good quality pre-salt clastic reservoirs. These Nile Delta derived sediments are predicted to extend into the northern sector of the Levantine Basin, thus depositing offshore Lebanon. The 10,000 sqkm 3D dataset helps to reduce the geological uncertainty and helps identify the presence of channels and fan systems across the Levantine Basin. Biogenic gas is now proven in many clastic and carbonate discoveries in close proximity to this region. In addition, the narrow margin and deeper sections of the basin are believed to have the potential for additional thermogenic oil prone source rocks charging both deeper basin clastics and rifted Mesozoic carbonates units along the Levant Margin. With the opening of the 2nd Licensing Round imminent and the first wells offshore Lebanon scheduled for 2019 the industries attention remains focused offshore Lebanon and the general Eastern Mediterranean province.

  • Mode conversion noise attenuation, modelling and removal: case studies from Cyprus and Egypt

    Author: Jyoti Kumar, Marcus Bell, Mamdouh Salem, Tony Martin, Stuart Fairhead
    First Break - 3 December 2018

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    The authors propose a method to attenuate converted mode energy to improve the imaging for prospective sub-salt targets.

  • Velocity model building in the major basins of the eastern Mediterranean Sea for imaging regional prospectivity

    Author: Ahmed El-Bassiony, Jyoti Kumar, Tony Martin
    The Leading Edge - 1 July 2018

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    Hydrocarbon prospectivity in the eastern Mediterranean is challenged by the presence of the Messinian salt layer, which varies in complexity across the area. The macro salt layer geometry itself varies from the deep abyssal planes in the middle of two major basins (the Herodotus and Levant basins), where it shows simple top and base relief to more complicated geometries near the continental salt-free shelf. Building depth velocity models for imaging the eastern Mediterranean basins requires accurate determination of the complex salt top and base, as well as accurate estimation of their velocities. Since 2006, many 2D and 3D megasurveys using conventional and dual-sensor acquisitions have been carried out across the area. Regional and relatively simple velocity models are used to image the Messinian salt layer extensions from offshore West Egypt to offshore Lebanon, passing by the Cypriot waters and the Eratosthenes Seamount. The data acquired include shallow and deepwater surveys, and technologies such as full-waveform inversion are applied to produce high-resolution images for the shallow post-Messinian section. Shallow-water imaging challenges such as acquisition footprint issues and low-angle illumination are solved by imaging with multiples using dual-sensor acquisition data. The Messinian salt layer is modeled with a simple constant regional velocity, while the pre-Messinian section is modeled with a simple combination of velocity gradient models. The regional model-building scheme introduces a good correction for the pre-Messinian structure and provides reliable multiclient data ready for outlining new prospects.

  • New Opportunities Offshore West Egypt

    Author: Simon Baer, Øystein Lie, Ayman Almorshedy
    GEO ExPro - 1 February 2016

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    Hydrocarbon exploration success offshore Egypt to date is mainly associated with the prolific Pliocene sequence in the Nile Delta Basin, but as the recent Zohr discovery shows, there are other potential plays to follow. Here, we look at the relatively unexplored area of offshore West Egypt.

  • Challenges and Opportunities in 3D Imaging of Sea Surface Related Multiples

    Author: Shaoping Lu, Dan Whitmore, Alejandro Valenciano
    SEG - 23 September 2013

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    Conventional shot domain migration constructs a subsurface image using the forward extrapolated (downgoing) wavefield from a source and reverse extrapolated (up-going) wavefield originating at the surface receiver positions. Similarly, sea surface related multiples can also be used to construct an image of the subsurface where the boundary data for the down-going and up-going wavefields are generated at the receiver locations via wavefield separation. After up-down separation the down-going and up-going wavefields act as the source and receiver surface wavefields and exist only at the receiver positions. To properly image the subsurface with the multiples, the down-going and up-going wavefields must be both recorded. Therefore, the streamer coverage, receiver density, source-receiver distribution geometry and acquisition shooting direction as well as target depth and subsurface dip are controlling factors in the effectiveness of imaging with multiples. For example, wide azimuth (WAZ) acquisition generates large streamer coverage and enhances the use of both the down-going (source) and up-going (receiver) wavefields. Anti-parallel shooting is typically required to reduce the source (down-going) wavefield directional bias and image both updip and downdip targets. Split-spread shooting geometry uses rays including downgoing and up-going wavefields recorded from different sides of the shot location and further enhances the subsurface illumination. In this paper, both synthetic and field data examples are used to demonstrate the challenges from acquisition geometry. A shallow water field data example shows the successful application of the technology to mitigate the acquisition footprint. The technology has the potential of reducing drilling hazard risks.

  • MegaSurvey Key to Understanding Prospectivity

    Author: Øystein Lie, Jörn Fürstenau, John Comstock
    GEO ExPro - 1 June 2013

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    The Ministry of Energy and Water of the Republic of Lebanon opened their first bid round on 2 May 2013 with a closing date of 4 November 2013. Twelve companies qualified as operators and 34 as non-operators and bids with consortiums of a minimum of 3 companies are invited.