Unconventional Approach to Re-Entry of Abandoned Well: Case Study of Saro-1 well

Abstract

There-entry of an abandoned well with a reclaimed top surface involves complex procedures and innovative technologies. A traditional approach is to prepare the location in such a way that the surface is at the depth where the casing was cut off before burial. Another conventional option involves welding the casing back to the surface. However, this approach could cause leaks in the future, hence there is need to utilize casing patch. This paper describes the experience gained in successfully re-entering and reviving a 43-year-old abandoned exploratory well, Saro-1. The wellhead consisted of a 20" conductor pipe capped with a cement plug. The challenges were in finding the buried well and safely bringing it to surface level. The re-entry operation involved constructing a cellar pit, installing casing patch, extending the severed casing to the surface, and performing wellhead installation. The paper further highlights the work programme designed and implemented to successfully re-enter and revive the well. Challenges encountered, best practices adopted and lessons learned from the operation are also described. The project's success underscores the importance of local knowledge, stakeholder collaboration, continuous risk analysis, and the use of bespoke solutions tailored to specific formation characteristics. Documented operations and constant technical engagement ensured clear communication and understanding among all personnel. This case study not only revived the Saro-1 well as a dual string multiple oil producer but also provided valuable insights and best practices for future re-entry projects, contributing to the industry's efforts to enhance production and address environmental concerns associated with abandoned wells.