white rose oilfield development application - Husky Energy

This system was evaluated as fourth preference on project cost and third on time to First Oil (Figure 1.3-1).1.3.2.4 Concrete Gravity Base StructureThe GBS concept evaluated is conceptually similar to that used on the Hibernia field. However, it hasan innovative design with the potential for much lower costs. The structure rests on the seabed and isdesigned to resist the forces imposed by iceberg and other environmental loads. The topside facilitiesinclude drilling equipment, as well as the process plant, with all wells drilled and maintained from theplatform. Oil is stored within the base structure and offloaded via a subsea pipeline to a loading buoylocated a short distance from the GBS.It is ranked second with the steel FPSO option based on feasibility. However, the proposed designrequires significant issues to be resolved before there is sufficient confidence in material quantities.These relate to risk assumptions with respect to the foundation design, where the soil strength isunknown, and local ice pressure loads.A significant challenge for the concrete GBS is considered to be deliverability, where the concept isranked lowest of the top five options.This system was evaluated as last preference on project cost and last on time to First Oil (Figure 1.3-1).It also showed a negative return on investment.The concrete GBS was ultimately eliminated as an option on the following grounds:• It is not economically viable for a field the size of White Rose as there are insufficient petroleumreserves established or likely to be established in the field to recover the cost of the GBS.• Its forecast construction cost is $507 million more than the steel FPSO option.• It has a forecast negative return on investment.• Of all options considered, it ranks the most unfavourably with the steel FPSO option based on costand deliverability.• Its construction is complex.• It requires a long lead time.• It presents substantial problems for decommissioning and abandonment, which would likely becomemuch greater liabilities over time. It is not practical for relocation for further service at another site.While the final decision on a production facility for gas will require a full review when the gasdevelopment conditions have been met, Husky Oil believes that the steel FPSO design developed for theWhite Rose oilfield will be capable of producing gas resources at White Rose should they be proven tobe economically viable.White Rose DA Project Summary • January 2001 Page 24