Characterization of Flow Patterns in Turbidite Reservoirs Using 3-D Modeling of an Outcrop Analog, Ainsa Sub-Basin, South Central Pyrenees, Spain

Labourdette, Richard¹, Patrice Imbert¹, Philippe Crumeyrolle¹, Eduard Remacha² (1) Total S.A, Pau, France (2) Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain

Hydrocarbon recovery in clastic reservoirs depends in good part on the quality of our understanding of the precise architecture of the sandbodies and the intervening shaly baf­fles and barriers. The complexity of hydrocarbon reservoirs and the uncertainties linked with the limitations of our investigation methods often make it convenient to develop and test concepts on better imaged equivalent outcrops. In the example shown, the issue was to define the main types of sedimentary heterogeneity that could be expected in a turbidite field from West Africa. Seismic interpretation shows that its overall architecture was that of a Laterally Offset Stacked Channel complex (ref.), but seismic resolution cannot go beyond that stage of interpretation. Analogue outcrops in Northern Spain were studied in detail to better document finer-scale heterogeneity, and modeled so as to provide guidelines for the actual modeling of the field. In particular, the influence of various types of heterogeneity (debris flow drapes at the base of individual channels, high permeability drains in the sandy channel-fill, geometric relationships and reservoir communication between channels and the associated levees, etc.) was tested using petrophysical parameters derived from the oil field so as to focus the final full-field modeling on the most significant ones, thereby simplifying the process. A seismic model of the outcrop was also carried out (once again using petro­acoustic parameters from the oil field) so as to help interpret precisely the stratigraphic rela­tionships on seismic, in particular pick the channel – levee boundary with the highest pos­sible precision.