The Atlantis OBS Project: Developing and Building the OBS Node Technology

Mitchell, Steve; Grisham, T.

doi:10.4043/17978-ms

Cited by 10 publications

(4 citation statements)

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“…A number of other companies have recently developed OBS nodes, notably Fairfield in co-operation with BP in the Atlantis project (Beaudoin and Michell, 2006;Michell and Grisham, 2006). While there are obvious superficial similarities among the models, (e.g.…”

Section: Development and Testingmentioning

confidence: 99%

A New Ocean Bottom Seismic Node System

et al. 2007

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractNew seismic technology aims at imaging the blind spots of conventional methods. One such new technology is Ocean Bottom Station (OBS) nodes. Such nodes record four component (4C) data; the water-borne pressure and the three components of seabed motion.Oceanographic Research groups have long been using OBS. After testing one of the leading brands of academic type OBS technology in 2002, we developed a commercial system which is deployed using Remotely Operated Vehicles (ROV). We tested the new OBS in 2006 in Louisiana.Wide azimuth geometry and well sampled common receiver gathers are natural for OBS. These provide better illumination and are suitable for 3D Wave Equation Migration (WEM). Better illumination and WEM enable improved imaging of complex structures under complex overburden such as salt. The P waves are recorded on both the hydrophone and the geophones and enable separation of the data into down-and up-going waves, which in turn enables demultiple and imaging of waves which are conventionally considered multiples and therefore discarded. Given the cost of deep water drilling, such improved imaging and demultiple can make the difference between success and failure when exploring challenging areas.Shear waves are recorded by geophones on the seabed. Such shear waves are generated by P to S conversion so they do not require special shear sources. The converted PS reflections provide additional information to what is in the PP reflections. The additional information provided by shear waves is useful for improved characterization of lithology and fractures.We present the engineering, design and field data from the 2002 and the 2006 tests. We used the data to test the coupling for P and S waves and demonstrate imaging with multiples.

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Section: Development and Testingmentioning

confidence: 99%

A New Ocean Bottom Seismic Node System

et al. 2007

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“…A number of other companies have recently developed OBS nodes, notably Fairfield in co-operations with BP on their Atlantis project (Beaudoin and Michell, 2006;Mitchell and Grisham, 2006). While there are obvious superficial similarities among the models, (e.g.…”

Section: Developmentmentioning

confidence: 99%

The Evolution of an OBS Node – From North Sea Tests to Final Design

Maxwell¹,

Grion²,

Ronen³

et al. 2007

69th EAGE Conference and Exhibition Incorporating SPE EUROPEC 2007

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A new design of ocean-bottom seismometer (OBS) system has been developed and tested that can provide high quality data in challenging deep-marine exploration and production areas.Each node records the pressure signal with a hydrophone and three components of seabed motion using geophones. The new units are self-contained recording stations, and are deployed by a remotely operated vehicle (ROV). They record seismic data on the seafloor for an extended period while a source vessel shoots lines above. Because they are autonomous, there are no cables joining the stations together. The nodes are therefore well-suited to working in congested waters, even right up to, or perhaps under, production structures. They also render 4D surveys practical because the ROV can redeploy the units close to their previous sites to ensure a high level of repeatability.The new nodes are differentiated from other types by improved levels of safety and efficiency; this is inherent in the compact, long-endurance, integrated modular design. The units also deliver high vector-fidelity thanks to excellent coupling to the seabed.We discuss the considerations, compromises, development and testing of these new OBS units.

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“…Additional papers associated with the deepwater OBS node project describe the pilot project for deepwater OBS, 2 explain the method and challenges involved in technology selection, vendor relationships, and equipment manufacture, 3 and detail the navigation and node deployment technology used in OBS data acquisition. The technology and the project methodology have evolved at each step, with the current solution probably being inconceivable at the commencement of the effort.…”

Section: Introductionmentioning

confidence: 99%

The Atlantis OBS Project: Managing the OBS Node Development Evolution

Openshaw

Beaudoin²

2006

Offshore Technology Conference

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractBP initiated the Atlantis ocean bottom seismic (OBS) project to acquire high-quality wide-azimuth seismic data from deepwater subsalt reservoirs. The project, focusing on the Atlantis field in the Gulf of Mexico, represents the first largescale commercial use of autonomous nodes as receivers. Prior to implementing this large-scale project, BP sponsored several sea trials. Conducting the sea trials accelerated the application of the technology to deepwater E&P, avoiding the long initial period of shallow-water implementation that has been the rule for much of today's deepwater technology. The primary goals of the sea trial were to validate hardware designs and operating method, develop budgetary production survey cost estimates, and record and assess the quality of the seismic data in the various seabed conditions. The critical decision in the planning for the sea trials was the selection of the node technology. A node from Fairfield Industries that combined the sensors and a recorder in a single pressure vessel was chosen for the sea trials. Investigations of deployment methods followed, with the requirement that the method would need to deploy the nodes efficiently and safely in the rugged topography of the Sigsbee Escarpment.With limited time available, the sea trials were able to perform both seismic tests and tests of the methods. Seismic tests included the effect of soil shear strength on seismic quality, a comparison of OBS node seismic data to existing towed streamer seismic, vector fidelity, PZ summation, and the quality of hydrophone data gathered at the sea floor. Tests of the method included node deployment and retrieval and some deck operations.From the sea trials, we concluded that the single pressurevessel node is a successful design for collecting OBS seismic data, and that new generation navigational techniques can provide accurate positioning, well within the requirements of the survey. The lessons learned from the sea trials directly benefit at-scale projects using OBS node technology, providing insights not only into improving the methodology, but also into project management techniques for large complex projects.

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The Atlantis OBS Project: Developing and Building the OBS Node Technology

Cited by 10 publications

References 0 publications

A New Ocean Bottom Seismic Node System

A New Ocean Bottom Seismic Node System

The Evolution of an OBS Node – From North Sea Tests to Final Design

The Atlantis OBS Project: Managing the OBS Node Development Evolution

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