Managing Risk Around Offshore Installations Using Autonomous Marine Vehicles While Conducting Exploration Activities

Abstract

Abstract The use of autonomous marine vehicles (AMVs) to do work in marine environments is a new and novel technology approach that reduces the presence of humans and improves safety withour compromising quality of service delivery. Over the last four years, this technology has grown and matured from a level of skepticism to full maturity. One particular AMV glider harnesses kinetic energy from wave action to produce forward propulsion in an environmentally friendly manner. This glider is a hybrid sea-surface and underwater vehicle that has taken the concept of autonomy beyond that of the autonomous underwater vehicle (AUV). This wave-powered sensor platform enables collection and transmission of data gathered at sea on missions lasting up to a year. It is capable of crossing thousands of kilometers of ocean to gather oceanographic data, as well as maintain a stationary position while taking meteorological readings, or it can circle a rig at a preset distance to provide early warning of security or environmental threats. Once deployed, the glider uses no crew, requires no fuel, and produces no emissions, thus eliminating both risks to personnel and impact on the environment. During a marine seismic survey, the worst possible nightmare is to have any of the seismic survey vessel assets, in particular the streamer spread, collide with the client's installations. This type of collision can occur due to metocean changes and feathering, unpredicted changes in the profile of currents, and the onset of cyclones and hurricanes. Typically, the knowledge of currents around platforms during seismic close pass acquisition (CPA) is provided by acoustic Doppler current profilers (ACDPs) that are bottom mounted on vessels that hold station just outside the 500-m exclusion zone, thus providing real-time currents information to help the seismic fleet navigate. This conventional method is an expensive use of the vessels held on station. Such vessels cost USD10 to 20 thousand per day, and typically these are chase vessels that have been pulled away from their primary duty, which is to chase away unwanted visitors in the area. The AMV provides an alternative; it replaces the vessel and performs the same work more efficiently at a much lower cost. At the same time, the AMV glider lowers HSE risk and reduces the environmental impact. To date, 35 missions have been completed using this technology, which has resulted in an operational savings of 2 to 3 days per month on average through better management of the CPA and line changes. Slowly, operators are accepting this technology as a viable replacement for vessel-mounted ADCPs.