Abstract
Abstract
Multilateral well design has established itself as being a reliable and well proven means of extending well life and increasing overall reservoir recovery factor. Modern multilateral junctions constructed within the Norwegian North Sea generally tend to be technologically complex, requiring hydraulic and mechanical integrity to allow for monitoring and flow control of up to four independent branches. As the technology has matured and the requirement to reduce well construction costs becomes apparent, novel methods of multilateral junction construction are being considered. One such method, involving creation of an open hole lowside exit in the reservoir, was recognized as a low risk solution in terms of complexity and cost.
This design removes the requirement for a cased hole window exit, however the potential compaction effects common on the field necessitate some means of mechanical support at the junction location to maintain lateral flow. This led to a collaboration between the operator, multilateral technology (MLT) vendor and advanced composite tubular developer resulting in a simple reservoir deployment system. This system allowed placement of a composite tubular within the primary mainbore, thereby enabling a means of lateral flow access and depth referencing for lateral creation. This system was deployed twice within the field with no non-productive time (NPT) associated with the operation, leading to successful drilling and completion of two dual lateral wells.
This paper discusses design considerations around the novel ML construction method including system requirements, configurations and a review of the operations performed.