Turbidites From Deep Water Campos Basin Visualized On 3D Seismic Attribute Volumes Using Stratigraphic And Structural Concepts

Many oil accumulations in deep water portion of Campos Basin, offshore, Brazil are located in<br>Oligocene/Miocene, sand-rich turbidites that consist of contrasting architectural types.These reservoirs<br>comprise up to 50 m-thick, 1-5 km-wide, and 2-10 km-long lobes displaying compensation stacking patterns.<br>These turbidites have high structural dips and also high variability in spatial distribution and heterogeneities.<br>They show seismic reflections mostly embedded into a single amplitude trough meaning a relative decrease of<br>seismic impedance, which can not be followed or resolved by conventional mapping using either automatic or<br>hand tracking. The geometry and resolution of such reservoirs are fundamental for the positioning of high-cost<br>horizontal and multilateral wells. For these turbidites we need more than conventional concepts of seismic<br>stratal surfaces to visualize their stacking pattern because we can not recognize a single frequencyindependent<br>event that can be used as a stratigraphic datum for attribute slicing. Furthermore the simple but<br>good concepts of stratigraphic volume visualization strategies as time windowed, detection and horizon keyed<br>also need tobe enhanced to isolate them because these technologies are based on the values of physical<br>samples and normally the attribute-strenghts into the stacking pattern have subtle or no differences. This paper<br>shows how to use concepts of seismic stratigraphy and structural geology combined with concepts of seismic<br>attribute transparency to visualize and map such turbidites from deep water Campos Basin. A geoadaptive<br>approach of 3D seismic visualization is introduced by using several relative seismic time-stratigraphic windows<br>in agreement with previous geological models and then mapping and detachment of depositional subystems<br>through variable-shifted surfaces from the attribute volume.