The Shuaiba reservoir of the Al Shaheen Field (Block 5 and Block 5 Extension, offshore Qatar) can be subdivided into a larger carbonate platform area located in the NE of Block 5 and an intra-platform basin (southern part of Block 5) that was filled in by a forced regressive wedge (FRW) system during the Upper Aptian regression. The FRW is characterized by clinoforms with a marly base that act as intraformational baffles or seals. Capturing these 3D geometries in detail, and specifically the exact location and nature of the platform-basin transition, is essential to developing the next generation geomodels for field development. Hence, an integrated study of core and log analysis, seismic forward modelling and seismic interpretation of a reprocessed data cube was conducted. As a start, a field-wide correlation grid of available core and log data allowed for an initial coarse understanding of the depositional geometries and defined an approximate location of the platform-basin transition. As a second step, the expected depositional geometries were forward-modelled in order to better understand possible seismic responses within the bandwidth of the available 3D seismic survey. A complication is the relatively small thickness of the examined reservoir elements that are close to the limit of vertical seismic resolution. Finally, seismic interpretation picked up on this groundwork and it was possible to clearly map the platform margin, as well as the onset of the FRW in 3D. The obtained result was a detailed 3D seismic interpretation of the Shuaiba reservoir geometries, where the interpreted elements are tied with a grid of core and log interpretations. The key elements in the successful Shuaiba interpretation was early adaption of fully integrated and iterative geological and geophysical workflows where forward modelling of seismic responses was important for hypothesis testing.

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