Remote Controlled (Tether-Less) High Pressure Isolation System

Abstract

Abstract The PSI SmartPlug is designed to isolate high pressure inside pipelines and risers, thus permitting pipeline maintenance and repair without losing the contents and without the need to flare, depressurise or decommission the pipeline. Use of this tool to isolate pressure also allows dry laying and tie-in during construction of new pipelines. The PSI SmartPlug comprises two Plug Modules, each of which is currently designed to withstand the full MAOP (Maximum Allowed Operating Pressure) differential pressure. Two bi-directional Pigging and Control Modules at each end of the SmartPlug ensure suitable pigging characteristics. The tool is designed to traverse minimum bend radii of 1.5D. The Control Module contains a hydraulic system with valves, battery pack, computer hardware and software, as well as an antenna that enables through-pipe wall communication. An Extremely Low Frequency (ELF) Subsea Communication Link sitting on the seabed outside the pipeline ensures through-wall communication with the SmartPlug inside the pipeline. An acoustic link ensures command and information transfer between the topside computer and the SmartPlug. The topside operator sends instructions to set and unset the SmartPlug, in addition to monitoring various parameters such as pipeline pressure, annulus pressure and status of the tool. The system is based on reliable off the shelf standard components and designed to ensure redundancy as required. Introduction The PSI SmartPlug (Remote Controlled Isolation Tool System) is a remotely controlled and operated (umbilical-less) pipeline isolation system used for isolation of oil and gas pipelines in all dimensions. They are designed, manufactured, and tested to withstand MAOP (Maximum Allowable Operating Pressure). Communication with the SmartPlug for typical subsea application is done from a surface vessel, via acoustic signals to a subsea module, then through the pipeline wall via Extremely Low Frequency (ELF) electromagnetic waves. All critical parameters such as pressures and temperatures are monitored. The SmartPlug design is fail safe, i.e., as long as there is at least 11 bar differential pressure over the isolation system it cannot unset. Thus any failure to the control system will not jeopardize the operation. This paper presents the SmartPlug system and describes the function and operation of each main sub-system. Further, experience from operations will be presented and discussed, together with identified challenges for further developments. System Description The SmartPlug comprises two isolation Plug Modules and two Pigging Modules (see fig. 1a). The PSI SmartPlug System consists of the SmartPlug, the Surface Control Center (SCC), acoustic modems, an ELF Communication Link (ECL) and Remote Actuation System (RAS) (see fig. 1b).