Integrated Lithostratigraphic, Formation and Structural Evaluation of the Migrant Structure, Sable Subbasin, Offshore Nova Scotia.

Abstract

Well data and 3D seismic are integrated to investigate the impact of sand-on-sand juxtaposition across a crestal fault in the Migrant Structure previously missed in 2D seismic. Pressure and petrophysical analysis of well data with seismic mapping of siliciclastic reservoirs and 3D geocellular modelling demonstrate the failure mechanism in the Migrant Structure. Depth conversion of seismic TWT surfaces at Migrant was done to ensure that the structure is enclosed in depth.

Results show that structural closure and reservoir quality diminish with depth in the structure. Also, there is increased displacement along the crestal fault in the shallow and intermediate sections where shale units are relatively thin with the termination of the crestal fault in areas of reduced net sand. Residual gas at different levels of the structure in well logs suggests that hydrocarbon migrated through the system with gas trapped below the crestal fault representing a different trapping mechanism.