A Success Story:Utilizing Different Variables in Design and Execution ofCoiled Tubing Extended Reach Milling Operations

摘要

The Shell Canada Fox Creek asset is located in West Central Alberta and has development activitiesfocused on the Duvernay reservoir.Efficient,horizontal,plug and perf wells,are key to delivering economicproduction from this unconventional light tight oil play.Unlocking more acreage per well,through theapplication of longer laterals,contribute significantly to CAPEX reduction.Although intervention-lesscompletions are a future aspiration,well intervention is still required for plug removal to assure stimulatedintervals are able to flow unimpeded.A number of initiatives were actioned collaboratively across serviceproviders and well delivery teams,to support well intervention to the limits of Coiled Tubing(CT)millingoperations on the FC734 D well.Considering the length of this well(7349mMD),a new string design was required to achieve themaximum depth as well as to provide the required WOB for milling operations.Horizontal wells withlong laterals,such as in this case,require heavy wall tubing in the vertical section to beyond the heelinto the lateral.Using a special custom-designed transition section in the Coiled Tubing string enabled theCT to reach the maximum depth.Utilizing fluid rheology application provided a means to keep track ofReynold's number in a real-time fashion to ensure turbulent flow regime downhole,and in turn,to optimizesolid transport as well as chemical consumptions.The application of fluid rheology resulted in wiperlessmilling operation in the extended reach applications.The flagship unit in the fleet was utilized in thisoperation.Generation four of the CT unit was designed in such a way that it can carry up to 8,345m of60.3mm(2-3/8in)CT pipe.There were different technological advancements,industry-leading features,andcustom engineering used in the design of this unit.Such features include customized PLC automation,user-friendly remote operation,advanced informative human-machine interface displays,and real-time dataacquisition and data storage from vast arrays of operational sensors.There is a twofold impact on the field development plan when the total measured depth(MD)wasincreased.First,this enables the operator to increase step out/generate drilling optimized trajectories withoutsacrificing lateral length.Second,the 400m/well increase in MD when applied principally to the laterallength netted an average increase of 250m/lateral in the subject area and reduced the well count by 4%(padcount reduction of 10%).The synergy impact of utilizing several variables resulted in successful operations.Those variables arefield development plan(well design),custom string design(CT reach),real-time fluid rheology(solidtransport),and the application of an advanced CT unit(equipment advancement).The successful delivery ofthe FC734 D well demonstrated the value of collaborative design and best practice sharing and has extendedthe technical design limit of well lengths across Shell Unconventional.