Solid Expandable Tubulars Enable Practical Well Re-entry in Mature Fields
The lack of available slots on offshore platforms necessitated consideration of a new approach to well re-entry programs in mature fields. An infilling drilling campaign in the offshore Zatchi and Loango fields in West Africa led an operator to explore a more economical and practical approach that reduces drilling time and maximizes the use of existing assets. Prior to initiating the plan, an analysis was made on the available alternatives to the retrieving and milling operations that often resulted in a long and difficult ordeal. Two alternatives considered included: • New drills with slot recovery • Re-entry with solid expandable tubulars The first alternative required further studies on the platform to use the slot-recovery deflecting tool. This process also appeared more expensive than the solid expandable tubulars and would require additional time to get the wells back on production. This paper will introduce the results of the application of solid expandable tubular technology on the two wells in the Loango and Zatchi fields, the difficulties of the operation and how they were overcome. An actual case history will be used to describe the safe and successful installation of solid expandable tubular systems through windows opened in existing casings. This paper will also explain how solid expandable tubulars facilitate enough hole diameter to install the necessary electric submersible pumps (ESP) without having to mill existing casing or find recovery platform slots.