Intelligent Coiled Tubing Systems: Overview, Research Trends, and Challenges

Abstract

In recent years, improving the efficiency of producing hydrocarbons from extended-reach horizontal wells has created a need to develop better well intervention, specifically coiled tubing (CT) solutions. However, because the conventional coiled tubing system only relies on surface data to monitor and predict downhole conditions, its application's effectiveness, accuracy, and efficiency still need to be improved. On the other hand, intelligent coiled tubing interventions use real-time downhole data to improve operational efficiency and performance. The objective of this paper is to present a detailed review of the fundamental principles and applications of intelligent coiled tubing systems and a discussion of the challenges and prospects of intelligent coiled tubing technology. Based on the different telemetry systems, the Intelligent Coiled Tubing technology can be categorized into three systems: Tube-Wire System, Fiber-Optic System, and Hybrid Electric-Optical Cable System. This paper will mainly focus on these three types of intelligent coiled tubing systems with a detailed review of the system functionalities, features, surface equipment, bottom hole assemblies, downhole sensors, and critical applications supported by case studies. A summary of the conventional coiled tubing equipment, tools, and applications is also included as technical background for the readers. The current technology status of the major operators is also summarized, representing the most advanced technology and service available on the market. In this study, we give a thorough overview of the Intelligent Coiled Tubing technology systems currently on the market and identify potential applications that intelligent coiled tubing can bring value to improve efficiency and performance. We also present several case studies of intelligent coiled tubing. Based on the case studies data, we summarize these critical applications and evaluate the values created using intelligent coil tubing systems. From the analysis, we find that the real-time monitoring, diagnosis, and decision-making functions of intelligent coiled tubing can efficiently solve operational problems in real-time, improve operational efficiency, increase tool life, and reduce downhole accidents while achieving increased production because of parameter optimization and correct decision-making. The paper introduces the working principle of intelligent coiled tubing technologies and case studies in various fields with different operational conditions. The proposed paper thus gives a clear and big picture of this topic from various aspects. We further extract and summarize the critical knowledge from the most recent case studies of intelligent coiled tubing technology. As a result, this paper will facilitate operators with less experience in intelligent coiled tubing technology to understand and apply this technique efficiently.