Abstract
The recent decline in crude oil production has needed more subsurface explorations to sustain and increase oil production in Azerbaijan. Consequently, this necessitated the developing and implementing a new strategy to drill slim hole side tracks from existing wells on a platform facing challenges with declining production and limited new slots. Nowadays, the drilling of slim hole sidetrack wells as a slot recovery technique is one of the most relevant and focused drilling technique. This type of drilling operation differs from conventional drilling methods due to many different operational challenges and limitations.
This case study aims to highlight the successful delivery practices of the dual casing exit slim hole sidetrack projects from the Gunashli field in the Caspian Sea. The paper focuses on sidetracking operation within the smaller casing sizes such as 6-5/8" and 9-5/8" by using design-specific technologies and executing a comprehensive planning strategy to eliminate different operational complexities. The study was aimed to share the experience of how slim hole sidetracking was planned and drilled successfully by managing various operational challenges such as high differential sticking risks, smooth passage of RSS UWD BHA through the window interval due to its stiffness, high loss possibility while drilling through depleted reservoir interval, trajectory control and high dogleg, casing held up due to trajectory complexity, tubular failure, vibration issues and others. It highlights valuable lessons learned and best practices during the re-entry operation, emphasizes measures identified and show the recommended way forward to optimize future operations in similarly complex and challenging wells by minimizing NPTs and eliminating costly remedial operations.
