Subsea wireless communications presents challenges and benefits

At the Subsea Wireless Group's (SWiG) quarterly Technical Capabilities and Standards Development meeting held in Boston last fall, participants discussed the standards that need to be developed for subsea wireless communications.

Tim Shea
ARC Advisory Group

At the Subsea Wireless Group's (SWiG) quarterly Technical Capabilities and Standards Development meeting held in Boston last fall, participants discussed the standards that need to be developed for subsea wireless communications. These include four primary technologies: radio frequency (RF), acoustic, free space optical (FSO), and hybrid (iterations of the three media). To meet the growing demand for subsea production systems, a number of industry stakeholders have taken it upon themselves to participate in SWiG to help develop and promote interoperability of subsea wireless networks to help benefit the entiresubsea and offshore oil and gas community.

The overall objectives of the not-for-profit SWiG are to:

  • Encourage dialogue between users to achieve interoperability of through-water communications approaches
  • Raise industry awareness and acceptance of through-water communications
  • Identify and develop needed industry standards for through-water communications
  • Encourage integration of subsea communication technologies
  • Promote best practices across the industry
  • Promote knowledge transfer across the industry.

SWiG membership currently includes the following companies: BP, Chevron, Statoil, GE Oil & Gas, Yokogawa, WFS Technologies, Sonardyne, Technip, Subsea 7, Teledyne Marine Systems, ABS Technology, Nautronix, JPL, MCSKenny, Octio AS, Saab, and Evologics.

According to industry sources, investment in subsea-related oil and gas projects is expected to experience robust growth over the next three to five years. Potential investment figures of tens of billions dollars annually, represent an attractive opportunity for technology suppliers and other stakeholders.

Given the challenges involved in subsea operations and the difficulties involved in transmitting data, voice, and/or video through the water, SWiG members realize the need to develop interoperable standards among the four main wireless communication technologies: RF, acoustic, FSO, and hybrid. Each communication option has its own strengths and limitations. The latter include effective range; data rate; bandwidth; immunity from noise, EMI, or turbidity; and power requirements. No one option addresses all the potential applications' individual requirements.

Acoustic communication is relatively well established within the subsea control field, with many suppliers offering some sort of non-interoperable acoustic wireless solution for ROV/AUV-related operations, monitoring, and asset positioning. Acoustic is often considered a backup technology for communication and control of BOPs and other similar devices, and can also be used for low-data rate telemetry. The effective range of acoustic communications is typically between 10 and 30 km (6.2 and 19 mi) at 1 KHz, but some meeting participants cited longer ranges when operating at lower frequencies. There is a tradeoff in terms of effective range and frequency, which limits acoustic's operational envelope.

RF is effective at much shorter ranges and, within the effective communication range, offers much higher data rates than acoustic communications. SWiG plans to use the Wireless HART and IEEE 802.15.4 standards as a foundation and modify as needed to meet the specific requirements of subsea applications. However, much like each of the communications options, RF has its own tradeoffs in terms of effective data range, interference issues, latency, and determinism.

FSO offers the highest bandwidth and is immune to EMI, acoustic back-ground noise, and background sunlight issues. However, its tradeoffs relate to interference from turbidity, limitations due to beam scattering and beam absorption, and the requirement for more accurate alignment of sender and receiver.

Eliminating or reducing the need to deploy long-distance "ocean-bottom cable systems" and/or copper and fiber-optics systems for subsea communications (with their high acquisition, installation, and maintenance costs) could provide significant savings for owner-operators of offshore E&P assets; likely in the tens or hundreds of millions of dollars on a worldwide basis. Wireless communications would also enable subsea assets to be deployed faster and more efficiently.

In addition, fiber-optic, long-distance copper-based, and ocean-bottom cable systems each possess their own technical limitations ranging from the need to for specialized wet-mate fiber-optic connectors and repeaters, plus noise interference, and higher power consumption. Wired subsea communications approaches also typically involve greater total cost of ownership (TCO) than with wireless deployments.

Assuming that the technology matures, performance improves, and standards such as SWiG radio emerge to enable interoperability and improve cost-effectiveness, deployment of wireless subsea communications should increase in a number of applications. These include collecting data from subsea assets from an ROV/AUV and then transmitting those data to a topside or land-based system and transmitting live video of ROV/AUV operations.

Other applications mentioned at the meeting included wireless monitoring of subsea production trees; "non-critical" control systems; wireless pipeline inspection and monitoring; communications of data, video, and voice; asset positioning; installing unplanned sensor networks; fixed structure and non-fixed structure and equipment asset integrity management; decommissioning, riser, and/or mooring monitoring; "black box" recording and low marine rise package (LMRP) to BOP connector; among others.

Additional applications that could be served through FSO communications include 2D and 3D mapping, laser imaging, laser illuminators, and laser ranging. SWiG meeting participants all agreed that the number of applications would only grow as adoption increases and users gain greater confidence in the capabilities of subsea wireless communications.

Major E&P operators, such as Chevron, BP, and Statoil; and oilfield service companies, such as OneSubsea are active participants in SWiG membership. To the best of ARC's knowledge, Yokogawa and GE are the only automation suppliers playing an active role at this point in time. These leading companies clearly recognize the value that developing interoperable subsea wireless communications standards can provide to owner-operators they strive to meet today's significant oil and gas industry challenges.

ARC recommends that any E&P company active insubsea operations, including tiebacks to offshore platforms, should learn more about the SWiG radio standard. Non-member end user companies can ask to be invited as a one-time guest at one of SWiG's quarterly meetings.

Oilfield service suppliers, automation suppliers, and wireless communications suppliers (RF, acoustic, and/or FSO) should consider participating in SWiG in order to learn more about the technical requirements involved in subsea operations, share their own expertise, network with potential customers, and help shape the future direction of the subsea wireless standards.

More in Subsea