ABSTRACT: 3D Structural modeling of the Kutubu oilfields, PNG

Oil production from anticlines in the Papuan Fold Belt is well established, yet their 3D geometry is poorly known due to karst limestone and jungle cover limiting data acquisition. The 40+ wells, surface mapping and aeromagnetic data in the Kutubu production area, together with better seismic data and improved understanding from analogue models allow the construction of 3D models. The interpretations are tested and enhanced by 3D structural restoration.

Within the Kutubu production licence, detailed structural modeling and restoration using the fault parallel flow algorithm within 3Dmove enables detachments and imbricated zones to be restored, using variable heave while independently varying the shear applied to the hangingwall. Models of the Moran and Iagifu-Hedinia structures restored using 3Dmove have led to interpretations of lateral variations in fault geometry, the formation of imbricated forelimb thrusts attributed to decreasing dip of the frontal thrust and to the prediction of structural compartments. Using SAR images to interpret surface structural fabrics to predict compartmentalization is misleading in PNG due to vertical variations in mechanical stratigraphy. 3D modeling of mesoscale analogue outcrops from Cape Liptrap, near Melbourne, suggests that the variation in mechanical properties between the Darai and Ieru Formations require the presence of a detachment and the refraction of fault planes, influencing the location of structural compartments. The test now is to use analogue structures to predict the subsurface 3D geometry prior to drilling.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia