Abstract The Great White and Silvertip Fields are located in the southern Alaminos Canyon area of the far western Gulf of Mexico. Shell is the operator of the Great White and Silvertip Fields. Along with Shell, Chevron and BP are the Great White JV partners. Chevron and Shell are JV partners in the Silvertip Field. This paper will provide an overview of the current Great White Field WM12 reservoir development plan, will compare the results of the recent six development wells with the pre-drill predictive model, and the impact of the well results on our understanding of this frontier area, Paleogene age reservoir. In addition, excellent results in two horizontal wells drilled in the Silvertip Field shallow M. Frio reservoir are also highlighted along with the well construction challenges in drilling and completing them. Oil in the Great White Field WM12 Sand reservoir is trapped in a large, highly faulted anticlinal structure. A high-resolution 3D seismic survey shot over the field has enabled us to map this structurally complex field reservoir in detail, identify hundreds of faults, and estimate reservoir thickness and quality away from sparse exploration and appraisal well control. The Great White JV partnership plans a staged development of the WM12 Sand reservoir. Staged development of this frontier area, ultra-deepwater field mitigates the downside production risk associated with Great White's structural uncertainty, the scarcity of well data, the lack of reservoir production data, and the potential for reservoir compartmentalization due to sub-seismic faulting and / or stratigraphic barriers to flow. Development drilling at Great White began in 2007 and to-date six pre-drill wells have been drilled and completed prior to first oil. Well results drilled prior to first oil at the Perdido Spar and at the subsea Southwest Cluster locations are in-line with our pre-drill expectations and so far, have confirmed our large estimated oil-in-place volume in the WM12 Sand reservoir in the field. The M. Frio oil reservoirs at Silvertip Field are located in shallow M. Frio canyon-fill sands. The M. Frio is relatively unconsolidated and contains high viscosity, heavy oil. Because the M. Frio reservoirs are relatively shallow, drilling margins are very low and the wells push the boundaries of extended reach drilling. With detailed planning, we have been successful in drilling and completing these long horizontal wells and had better than expected well results.