A Coiled-Tubing-Deployed Downhole Video System

Abstract

This paper describes a fiber-optic downhole video system deployed on coiled tubing. A state-of-the-art inspection system has been developed that combines proven coiled tubing components, innovative cable termination methods, and the latest downhole video and fiber-optic cable technology. This new system has the capability to visually inspect horizontal wells, to displace opaque liquids in the desired viewing area by locally injecting clear fluids, and to obtain high resolution video at greater depths than possible with other camera systems. Testing indicates that this system provides improved versatility and video quality. This paper includes a complete description of the components in the downhole video system. HISTORY Interest in downhole video most likely began with the introduction of television, when the possibility of seeing well conditions downhole suddenly seemed realistic and certainly desirable. As early as the 1950's, patents were issued for the use of downhole video cameras. In the 1970's the first downhole cameras were used successfully in shallow water wells and soon became commonplace in the water well industry. Wireline Deployed Cameras Since the 1970's, downhole video cameras have been deployed on wireline units to visually inspect and record conditions downhole. As the downhole cameras were used in deeper and deeper environments, problems of telemetry, high pressure and temperature, functional ocular material, lighting, and condensation had to be overcome. Advances in video equipment and in oil field technology have led to the development of downhole video cameras that are capable of working in extreme, deep environments. Common applications for wireline-deployed downhole video include the following : Leak Detection: Normally the resolution of the camera is goodenough to detect turbulence created by a leak or to identify different fluids leaking into the wellbore. Particulate matter flowing through a hole is usually easy to detect. P. 291^