An intervention program in a well may require the use of both electric line and slick line to convey a variety of services. This calls for the swapping between conveyance systems, often multiple times in a single intervention program. A viable solution is a new system for carrying out interventions in oil wells which is designed to convey electrical, electro-mechanical and mechanical services. The paper aims to describe this new conveyance system and discuss field experience to date.
Carbon composite material technology confers the benefit of higher strength at reduced weight when compared to conventional cable materials and the slick surface eliminates the need for grease injection pressure control systems. The ability to perform both precision logging and heavy duty mechanical services within the same rig-up allows complex well programs to be executed with only one unit and a multi-skilled crew.
The first field trial for the new conveyance system was conducted offshore in the North Sea, and proved the carbon composite rod capable of performing both mechanical intervention (16 runs) and electric line (12 runs) services. The strength of the rod material enables the running of long and heavy bottom hole assemblies. Run in conjunction with electrical or mechanical release devices, the carbon composite rod is able to deploy strings beyond the capability of conventional wirelines.
The physical strength and rigidity of the rod, coupled with its light weight, allow efficient planning of intervention programs where mechanical and electric services are combined in a single rig-up. Since the first trial, advances in technique have brought 10km (32,000 ft.) rods to the field enabling intervention access to, and perhaps more importantly retrieval from, extended reach wells. Equally of interest is the ability of the rod to access short lateral sections without resorting to tractor technology, allowing faster and more economical intervention.