Abstract
For a number of years, the exploration and production industry has sought to prove the feasibility of monobore expandable liner extensions as an advantageous alternative to conventional casing designs. Included as part of the initial casing design, the goal of an expandable monobore liner extension is to enable the operator to drill deeper exploration and production wells with larger hole sizes at the reservoir. As a contingency plan, the goal is to enable the operator to isolate zones that contain reactive shales, sub-salt environments, low fracture gradient formations or other drilling situations without having to reduce the casing and subsequent drilled hole size into the reservoir. A one-trip, top-down expansion system was developed and tested to prove the feasibility of the expandable monobore liner extension concept, including the ability to provide an optimized, cost-effective casing configuration without reducing drilled hole size. During the development process, the need for expandable open-hole packers or optional cementation of the liner was identified and addressed. This paper details the development process for the expandable monobore liner extension system, including testing and the resulting commercial field deployment in an operator well to qualify the technology.
This paper will demonstrate the challenges faced during various planning and execution stages and explain how those challenges were met, specifically in the following areas:
Pre-planning wellbore design options and considerations
Monobore liner extension selection, one-trip system reliability
System qualification
Zonal isolation requirements
Field installation considerations
Expansion process
Safety and environmental impact
Post deployment results
