New Age of Coiled Tubing CT Oriented Perforation—World First Application for Intelligent Completion in Hostile High-H2S Well

Abstract

Well completion and commissioning operations offshore present a variety of technical and operational challenges in the quest to maximize well productivity and optimize the economic value together with focus on safety. This is very relevant to perforation operations performed in hostile and high-pressure reservoir conditions encountered in a complex development project in the Caspian basin. The degree of complexity is increased due to required oriented perforation in a deviated intelligent completion well equipped with well monitoring system mounted on the outer side of the production liner. We describe the developed innovative technical solution for oriented perforation, challenges encountered, lessons learned, and results of this first-time-in-the-world implementation. To meet job objectives, we selected electric-line enabled (e-line enabled) coiled tubing (CT) for precise depth control, the latest-generation advanced gun deployment system (15,000-psi working pressure 5.12-in. ID H2S-rated) for conveyance of long gunstrings under pressure paired with specially developed hostile oriented gun system, and newly designed CT perforation string components, such as the perforation-shock-resistant bottomhole assembly (BHA), two independent emergency disconnects, high-tensile CT logging head disconnect weak points, perforation passive casing orienting device, and tuned software to predict and evaluate shock load and dynamic underbalance. The oriented perforation job was successfully completed with this innovative oriented method for perforation applications—passive casing orienting device for deviated wells. This perforation technique proved capable of providing desired orientation accuracy and effectively minimized operational time and associated risks. Such approach allowed safe and efficient perforation in a controlled well environment and provided perforation in the desired direction away from downhole well monitoring equipment and with accurate depth control, and managed detonation shock load in overbalanced conditions, which avoided any well fluid influx or H2S release. The developed solution is a seamless integration of e-line enabled CT, the CT logging head, a gun deployment system for pressurized well conditions, and a set of wireline tools and specialized perforation equipment for passive orientation. This is the first time that the described oriented CT perforation operation using such innovative techniques has been performed in the world. The experience demonstrates a method to safely and efficiently facilitate challenging oriented perforation jobs in the future for intelligent completion applications and a great opportunity for well performance evaluation through distributed temperature-sensing analysis.