Acquisition With Autonomous Marine Vehicles: Field Test

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 183869, “Acquisition With Autonomous Marine Vehicles: Wave Glider Field Test, Offshore Abu Dhabi,” by M.A. Benson and T. Lecoq, ADMA-OPCO; G. Mercado and S. Nakayama, formerly of ADMA-OPCO; N. Moldoveanu, P. Caprioli, and G. Nyein, WesternGeco; and S. Pai and E. Yandon, Schlumberger, prepared for the 2017 SPE Middle East Oil and Gas Show and Conference, Manama, Bahrain, 6–9 March. The paper has not been peer reviewed. A field test was conducted with autonomous marine vehicles (AMVs) and 3D sensor arrays (3DSAs) to record and compare seismic data generated during an ocean-bottom-cable (OBC) survey. The test was a field verification to check that the AMV platform and the sensor array can deliver high-quality seismic data in a form that can be successfully processed and compared with ocean-bottom fixed-receiver data. The feasibility test conducted offshore Abu Dhabi demonstrated the successful and safe deployment, seismic-data acquisition, and retrieval capabilities of the AMV and 3D sensor array. Introduction AMVs are an alternative to conventional methods of acquiring marine seismic data; they are designed with the aim of increasing offshore safety and reducing risk while delivering a quality service within lower-cost pricing models. These unmanned vehicles have expanded the envelope of offshore operations and have been instrumental in increasing productivity and safety in marine environments. Such vehicles, because of their low profile and flexibility in maneuvering around obstructions, can be placed close to obstructions, reducing the risk typically involved in operations of this nature. The vehicles have proved capable of carrying out a wide range of vital ocean-monitoring functions formerly assigned to manned vessels over a longer time period and provide a viable alternative or supplement to acquiring seismic data in cases where adverse existing factors may impede standard acquisition methods. AMVs The AMV used for the test offshore Abu Dhabi is a hybrid sea-surface and underwater vehicle that has been proved to enhance exploration and production in marine environments by collecting and delivering real-time measurements in areas formerly too costly or too challenging for operation. The wave-powered sensor platform enables collection and delivery of data gathered at sea on missions lasting up to 1 year. The AMV is a two-part system that consists of a surface float and a submerged glider, connected by a high-speed communication umbilical tether (Fig. 1). The vehicle’s propulsion system is passive and mechanical; it exploits the natural difference in wave motion between the surface float and the submerged glider to convert energy from wave motion into thrust. Articulating fins attached to the submerged glider convert wave energy and generate thrust as they pivot vertically. The vehicle produces forward propulsion independently of wave direction as its float moves up and down with each wave and the submerged glider tows the float forward.