Jonny Hesthammer¹, Francisco Porturas²
(1) Statoil, 5020 Bergen, Norway
(2) FP Geo, 4041 Hafrsfjord, Norway

Abstract: Subsurface Integration - the Fifth Dimension: A Case Study From the Gullfaks Field, Northern North Sea

In order to fully understand the structural reservoir characteristics, it is necessary to integrate results from detailed analysis of core data, dipmeter data, image data, well log correlation data, seismic data and field analogue data. Such an integrated approach will allow for a fuller understanding of variations in fluid flow patterns within the reservoir and optimal placing of wells.

We present an example of integrated analysis carried out on the Gullfaks Field, Northern North Sea. In this case study, dipmeter data (here exemplified by the use of resistivity imaging data)from well 34/10-B-12 and seismic data helped in finding the orientation of a fault associated with 69 m missing section (as observed from well log correlation data). Core data from the well allowed for examination of deformation structures as well as permeability and porosity measurements. From thin section analysis it is possible to observe how phyllosilicates effectively seals the micro-fractures (deformation bands), thus restricting fluid flow across the fractures. Core data demonstrates that all faults in the sandstone reservoir on the Gullfaks Field are associated with numerous deformation bands in a narrow damage zone near the fault. Since each of the deformation bands restrict fluid flow, an understanding of the spatial distribution (from well data, seismic data and field analogue data) and petrophysics (permeability and porosity) associated with faults on the Gullfaks Field is crucial in order to optimize field development and in cases where 'downhole factories' could be the future scenario.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana