PROCEEDINGS, INDONESIAN PETROLEUM ASSOCIATION Thirtieth Annual Convention & Exhibition, August 2005 ENHANCING CONSISTENCY BETWEEN GEOLOGICAL MODELING AND SEISMIC PRE-STACK AMPLITUDE INVERSION WITH PSEUDO-WELLS: AN EXAMPLE FROM THE GENDALO FIELD

Integration of a low frequency model during seismic inversion enhances the qualitative and quantitative interpretation level of inversion results. Information required to build a low frequency model primarily comes from well data. In some geological environments it is possible to make simple extrapolations of the well data within a basic geological framework to provide a reasonable low frequency model. Often greater geological constraint is required, which can be incorporated in various ways. In this case study we present a novel approach based on the use of pseudo-wells. The Gendalo field in the Kutei basin comprises a series of laminated gas sands deposited in a deepwater setting. Quantitative models of the distribution of gas sands are difficult to produce because of ambiguities in the seismic response to variations in fluid content, sand thickness, and reservoir quality. We designed a workflow that brings together geological understanding of the depositional environment with the geophysical process of prestack seismic amplitude inversion. An initial geological model was built in terms of reservoir netto-gross (NTG) and fluid flag with information from four wells, seismic attributes, and a conceptual geological model. A transform between NTG and elastic rock properties enabled conversion of the