Complex near-surface conditions and subsurface geology pose problems for seismic imaging in Western Desert and require new survey design approaches, sensor technology and processing techniques. In Aghar SW Field in West Razzak Development Lease (Western Desert) the main reservoir is the Bahariya Formation but hydrocarbons were found in some wells also in the Kharita Member.

This paper presents a case study from Aghar SW Field where conventional 3D surface seismic could not resolve the hydrocarbon bearing sandstone layer intercalated within shale in the Kharita Member and the decision on planning an additional development well was very difficult.

Borehole seismic was considered as a viable solution to enhance the seismic resolution and map the extension of a sub-seismic hydrocarbon bearing layer. A cost effective multi-azimuthal VSP survey was designed in Offset VSP configuration placing seismic energy source at different source offsets and azimuths around Aghar SW 5 ST Well.

Data were acquired using 3-component multi-shuttle Versatile Seismic Imager tool as downhole geophone and vibroseis as seismic energy source. Multi-component processing was carried out in Walkaway VSP configuration combining the data optimally. VSP high resolution images resolved successfully the thin lenticular productive sandstone layer and the location for Aghar SW 6 Well was chosen accordingly.

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