Thirty Years of Successful Coiled Tubing Re-Entry Drilling to Enhance Production in Mature Assets

Abstract Many oil and gas fields are approaching the end of their productive life. Production rates are declining, forcing operators to decide whether to shut down production and plug and abandon (P&A) the wells or explore cost-effective revitalization methods instead of drilling new wells. Coiled Tubing Drilling (CTD) has been used for over 30 years to improve production rates in aging fields. This technology has evolved in response to changing operational objectives and increasing technical requirements, becoming a robust and reliable solution for enhancing production in mature fields. Today, most operators are reviewing their existing, aging assets and evaluating solutions to revitalize fields while maximizing the recovery factor. CTD has emerged as a preferred method for re-entering existing wells and accessing undrained reservoir sections at a fraction of the cost of drilling a new well. This paper examines the evolution of CTD technology, drawing insights from past lessons and technological advancements. It covers the progression from the first-generation CTD bottom hole assembly (BHA) in the 1990s, to the second generation with enhanced measurement capabilities and higher build rate performance, and finally, to the latest advanced high-temperature version. The development of these technologies is analyzed in correlation with evolving market requirements. Different regions have specific CTD applications and operational constraints. The Middle East, for example, has utilized CTD since 1998 and has been a key driver in the development of high-temperature-rated and H^S-resistant BHAs. Examples of successful longterm projects, spanning 15 to 20 years, will be presented to demonstrate the technical and economic viability of CTD for field redevelopment. Recently, the increasing demand for longer wells and more precise well placement has driven innovations in rib -steered motor technology. The first-generation rib-steered motor was designed to drill straight, long lateral sections, effectively mitigating early lockup issues experienced with conventional orienter-steered BHAs. The second-generation rib-steered motor introduced significantly higher build rates, making it suitable for both lateral and build sections. Future developments will continue to optimize these tools, particularly for high-temperature applications in the Middle East. Additional and optimized Logging While Drilling (LWD) services like Gamma and Resistivity which can measure into different directions will enhance reservoir placement and Geosteering capabilities for Coiled Tubing Drilling in the future.