Harrier Development: Successful Implementation of the World's FirstOffshore Multilateral Installation with Staged Acid Fracturing Performed onBoth Laterals

摘要

With a suppressed hydrocarbon sector over the past few years,operators,service providers and ancillarycompanies alike have been strongly challenged to collaborate,where feasible,on field developmentsolutions which offer greater economies of scale and efficiency by reducing operational time and cost.Thispaper details the evolution of the Harrier field development plan(FDP)in the context of innovation withincompletion and stimulation treatment design which has successfully created value for this North Sea gasoperator.Originally,the project plan comprised of two development wells,each accessing separate chalk gasreservoirs-Ekofisk and Tor which were approved by the UK Oil and Gas Authority in 2012 under theStella and Harrier FDP,with an estimated development cost of USD 250 million.During the conceptualphase,the project economics were not attractive even in a high oil price environment.Services providerswere then invited to provide alternative solutions to significantly enhance the investment appeal of thisopportunity with the aim of reducing capital and operating expenditure while enhancing both field recoveryand accelerated production.One such provider was successful with the proposition of a revolutionarycontraction of the FDP with a unique design concept of a single well development terminating in a duallateral with each leg targeting a separate reservoir in which fourteen acid stimulation stages per leg wereplanned to greatly enhance productivity.After several months of intensive collaboration,the optimized welldesign was completed and the project was sanctioned with field development cost reduced by a full 50%.The paper provides an overview of the stimulation design,based on the reservoir challenges encounteredand the progression of the completion design explored,into its final fit for purpose realisation.Results inrelation to achievement of well objectives,service delivery,change management during the execution phaseand most significantly overall well performance are also provided.The objective of this paper is not only to demonstrate the value created to the field operator,butalso to illustrate how planning and developing a unique solution was strongly influenced by a costsensitive environment for efficiencies gained,with regards to risk management and mitigation,along withcontingency planning.Furthermore,through a multi-segment integrated approach experience,numerous lessons learnt and best practices were harnessed for use when venturing on similar projects championingtechnical innovation under economic and resource constraints.