Isharat-1 Multi-Azimuth VSP

Pieter Van Mastrigt
SRAK, Saudi Arabia
[email protected]

On its first exploration well SRAK successfully acquired a multi-azimuth vertical seismic profile (VSP). In addition to zero-offset data, four azimuths were acquired at large offsets from the wellhead (greater than 3 km). Acquisition of this VSP data involved the manufacture and mobilization of dedicated equipment and was hampered by considerable logistical challenges. These resulted from the remoteness of the well location, multitude of suppliers, tool failures and timing, all of which provided invaluable knowledge and experience on VSP operations. After processing of the data and an integrated evaluation, we improved our understanding of the seismic-to-well match, and in particular, we developed a better appreciation of the presence of multiple systems in the surface seismic data. This is of significant importance as these multiple systems mask part of the targeted sequence, and a better understanding yields an improved outlook on their removal. The imaging results within a very large VSP aperture remain challenging; however, after careful review, we found hints as to how the source-rock sequence may have been deposited. In this presentation we will discuss the design, acquisition, processing, and evaluation of the data, and the experience that was gained for future VSP programs in this environment.

AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain