ABSTRACT
Different lobe models imply significantly different reservoir geometries; thus, one must apply the proper lobe model to ancient fan sequences. Braided suprafan lobes are characterized by stacked channel sand bodies with good lateral and vertical communication, and they constitute excellent reservoir facies. Depositional lobes, composed of sheet-like sand bodies with good lateral and moderate vertical communication, exhibit properties of good reservoir facies. Fanlobes, which refer to meandering channels and associated levee facies of large mud-rich submarine fans such as the Mississippi fan, are characterized by offset stacked sand bodies with poor lateral and vertical communication. These lenticular sands have the potential to be moderately good reservoir facies. Ponded lobes, which represent mud-rich slump facies of slope environments, comprise poor reservoir facies because of low sand content and poor sand-body connectivity. Furthermore, the presence of contorted mud layers in ponded lobes is expected to hinder fluid flow. External mounded reflections in seismic profiles often are interpreted as lobes; however, there are no definite seismic criteria to delineate mud-rich lobes from sand-rich lobes.
