A detailed description and mapping project of the Kuparuk reservoir at Milne Point field culminated in the development of a unique original uncertainty model. The model is unique in that all uncertainty aspects of each variable in the volumetrics equation are reviewed. Over 200 wells penetrate the Kuparuk reservoir at Milne Point field. New full-field maps were needed to update the full-field description with the past five years drilling results and to assist in reservoir management and infill drilling. A new base Kuparuk structure map was generated from geophysical mapping and the well control. Structure, gross isopach, net isopach, porosity, water saturation, and oil pore volume maps were generated for each Kuparuk zone. Gross isopach maps were generated for each Kuparuk zone from correlating the zone penetrations in the field and merging them with the zone correlations in the adjacent Kuparuk field to help preserve regional zone trends. Structure maps for each Kuparuk zone were created by stacking the gross isopach maps onto the new base Kupaurk structure map and ensuring their conformance to the well control. Net sand maps were created from a net sand calculation of the well logs and from trend form gridding to the gross sand maps to properly preserve net sand trends. Porosity maps were created from log analysis. Water Saturation maps were created from log analysis and from a detailed analysis of the multiple oil-water contacts in the field. Together, these maps were used to generate oil pore volume maps and a most likely original-oil-in-place calculation.

An original uncertainty model was developed and implemented to calculate the statistical range of bulk rock volume and oil-in-place by zone and by hydraulic unit. Hydraulic units were defined by studying cross-well communication and likely sealing faults associated with different oil-water contacts. The uncertainty model calculates the statistical ranges of bulk rock volume as functions of variable oil-water contacts and structure, porosity, oil saturation, net sands, and oil-in-place by zone and by hydraulic unit and determines how to best mitigate uncertainty and manage access to the nearly one billion barrels of oil-in-place. The model calculates the statistical importance of these variables in the bulk rock volume and oil-in-place equations and is capable of handling multiple dependent variables. Variable importance can be used to mitigate the larger ranges of uncertainty by focusing further technical study on the most leveraging variable(s). The model allows independent variation of structural and oil-water contact uncertainty by zone and by hydraulic unit. A summary map of the uncertainty results for Kuparuk Zone A1 demonstrates the value of this process for reservoir management and focusing of further technical study. The entire process could be favorably adapted and implemented to assess the bulk rock volume and oil-in-place uncertainty to help improve reservoir management of the giant Kuparuk field to the south.