APPLICATIONS OF FIBER OPTIC ENABLED COILED TUBING OPERATIONS ON THE ALASKAN NORTH SLOPE

CT services performed on the North Slope range from fill cleanouts, to stimulations to fishing jobs. The difference between the success and failure of many CT operations including fill cleanout, matrix stimulation, and cementing jobs relies heavily on the knowledge and prediction of the behavior of downhole parameters such as downhole pressure and temperature. A large portion of CT operations such as setting tubing patches or packers, CT conveyed perforation, fishing operations, and zonal isolation depends on highly accurate depth control to ensure the intended result of the operation.

This paper presents a CT system that allows real time monitoring of downhole pressures and temperature, with a casing collar locator (CCL) for depth correlation without the limitations of conventional wireline (E line) enabled coiled tubing units. Unlike most E line CT services, this new system is designed to be compatible with virtually any common CT service work application including cementing, sand slurry placement, ball pumping, and acid stimulations.

The system consists of downhole tools coupled to a fiber optic bundle inside a small diameter fiber optic conduit. The fiber optic system provides real time transmission of downhole data to the surface. A surface interface module with wireless communication link is mounted inside the CT reel. This wireless communication link provides two ways communication between the downhole tools and the surface monitoring equipment.

The information presented in this paper summarizes application and analysis of the real time data acquired during the introduction phase of the service. Twenty seven CT operations were successfully performed using the system. This real time logging system demonstrated value in providing the crew with the information needed to understand and improve the efficiency of the operations being performed.