Comprehensive Use of Prestack QC in QI Workflows

We use a field example to illustrate the benefits of comprehensive access to gathers during preconditioning work for AVA inversion. We show that using prestack horizons, and attribute maps extracted from them, helps to de-risk prestack interpretation and inversion. The example comes from the Odin field. Data have various problems including residual multiples and residual moveout. Attribute maps constructed from partial stacks quantify these problems to some degree, but prestack maps give more detail and permit sharper definition. The prestack maps are also interpretation objects in their own right, allowing a very fast insight into the reservoir AVA behaviour. We show that fluid cubes derived from coloured inversion are sharper when associated with the prestack horizons than they are when obtained from conventional methods.