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An experimental multicomponent three‐dimensional (3D) seismic survey has been carried out over the Natih field in Oman. This paper describes the small‐scale two‐dimensional experiment carried out beforehand, and how the results obtained from this pilot were used to assess the feasibility of a nine‐component three‐dimensional (9C3D) operation as well as to determine the field parameters for the field‐scale 3D survey. It also describes the two VSPs and a wireline shear log, acquired in conjunction with the pilot experiment, and the importance of such borehole data for establishing the correct time‐to‐depth relationship for the seismic data and for providing an independent check on the seismic interpretation. The observation of cusps in the offset VSP indicated the strong anisotropy of the Fiqa shales overlying the Natih reservoir.

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Seismic and petrophysical data sets are processed to acoustic impedance. The petrophysical processing is divided into three phases.The first involves the preparation of a depthsampled acoustic-impedance log corrected for environmental effects. Re-sampling in time and band limitation of the acoustic-impedance log yields at the end of second-phase processing a synthetic seismic trace that can be used to identify lithological units on a seismic section.Third-phase processing provides the information necessary for interpreting seismic-amplitude values. As an example, the loop associated with a potential reservoir sand is identified and traced along several seismic sections. Amplitude measurements taken from this loop are interpreted in terms of expected fluid content, and a porefill-distribution map of the reservoir is constructed.

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