Multilateral Expandable Metal Anchoring Packer Design, Development, and Application in the North Sea

Abstract

Multilateral technology can provide a higher recovery factor of hydrocarbons by achieving a longer field life supported by the cumulative production of the multiple laterals, turning otherwise unviable reservoirs into economically sound targets while keeping construction costs down and minimizing risk. Application of expandable liner hanger technology to junction creation in multilateral wells can improve completion efficiency and flexibility by offering increased tensile and torque ratings along with larger IDs over previous solutions. This paper highlights the development, testing, and a successful case study of a new expandable anchor packer designed for a multilateral TAML Level 5 application in the North Sea. Well construction has changed in recent years with more operators turning to multilateral technology due to slot-constrained pads and a desire to increase reserves by combining targets that are separately uneconomical or improving the efficiency by extending the life of mature fields. The foundation to constructing a multilateral well is a reliable main-bore anchor point, which provides a service tool landing point from which a casing exit window is milled, and a lateral leg drilled and completed. Using an expandable anchor packer, based on an existing expandable liner hanger design widely accepted in the industry, provides a broader scope to position and orient the packer at the desired depth to begin lateral construction while providing increased completion flexibility through increases in tensile, torque, and ID capabilities. These improvements provide the capability to deploy screens directly below the anchor packer, eliminating the need for a separate trip with a liner deployment system (LDS). The larger packer ID makes the system compatible with a field-proven multibranch inflow control (MIC) junction. This new approach to an anchor packer for a multilateral TAML Level 5 junction provides not only increased load, torque, and ID capability, but improved sealing reliability as well. Validation testing has confirmed that the high-performance, advanced metal-to-metal sealing technology of this new expandable anchor packer provides a compliant metal-to-metal seal with a fully bonded resilient elastomeric seal, which can compensate for imperfections in the parent casing and provide isolation to a potential gas cap in the main bore below the lateral window. By employing field-proven expandable liner hanger technology with its superior load, geometry, and sealing capabilities to multilateral TAML Level 5 junction creation for a North Sea application, improved efficiency and flexibility in the completion can be achieved.