Downhole Leak Determination Using Fiber-Optic Distributed-Temperature Surveys at Prudhoe Bay, Alaska

摘要

Distributed Temperature Sensing (DTS) is an emerging technology which allows temperature measurement and transmittal along the entire length of the well. An enclosed fiber-optic cable is deployed into the well to allow a continuous, real-time snapshot of the well’s temperature profile. Since its introduction in 1995, DTS has had an increasing number of applications including determining production and injection profiles, monitoring stimulation operations, and performing gaslift surveys. This paper discusses DTS as a method for downhole leak detection based on a North Slope field trial conducted between 2004-2006. Twelve operations were performed using two different vendors’ retrievable DTS systems, successfully identifying tubing, production casing, sand plug, and packer leaks. Theory, case histories, and future improvements are summarized in this paper. Additionally, a comparison between conventional leak detection logs is presented along with the advantages and disadvantages of DTS surveys.