A detailed reservoir simulation model to aid BG (operator) and coventurers in Fleming Field management was created using a petrophysically based, seismic inversion scheme. The process incorporated all a priori geological and petrophysical data from 16 existing wells providing realistic predict of geology away from the wellbore with 4-6 times more vertical resolution than conventional impedance inversions. The study utilized proprietary Incremental Pay Thickness forward modeling (IPT) and Non-Unique Inversion (NUI) software.

Paleocene Maureen Sands constitute the reservoir of the Fleming Field. These sands comprise a submarine fan complex that onlaps the Jaeren High on the southeast margin of the South Viking Graben creating a classic stratigraphic trap. The inversion allowed more accurate prediction of the critical sand pinchout, sand thicks in paleo lows and fluid contacts.

The inversion process utilized the Maureen Sand reservoir isochron and petrophysically derived water saturation data as discriminators in waveform matching. This process required accurate interpretation of the hydrocarbon transition zone from depth-converted 3D seismic and well data. By using known field parameters as discriminators, the non-uniqueness of the inversion process was reduced and resulting predictions were more geologically reasonable. Results of the inversion show detailed stratigraphic layering with respect to effective porosity of Maureen Sands. The enhanced resolution is possible because the inversion process utilizes actual petrophysical data to create a suite of over 200,000 pseudo-wells which encompass all reasonable geological scenarios. These models are compared to the seismic waveform to select the best geological fit. Using this process, geological and petrophysical data were extrapolated away from existing wells to the remainder of the field thereby providing a predictive tool for future development.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah