Optical gauge carrier on downhole flowmeter. (Figure courtesy of SEAFOM)

An increase in industry acceptance of optical sensing systems has matched the fast-growing complexity of installations since the world’s first in-well fiber optics pressure and temperature gauge installation in 1993. The diversity of optical sensing techniques includes multiphase flowmeters and distributed temperature sensing (DTS) which, combined with remote zonal flow control, result in true intelligent completions able to gather real-time data on reservoir performance and adjust flow regimes.

Since that first installation the industry has accumulated in excess of 170 permanent pressure and temperature gauge installations, some 30 optical flowmeters (single, two and three phase), 40 seismic stations and hundreds of DTS installations. But practically all have been in offshore dry tree and land wells. It is no surprise, then, with the mounting influence of the offshore market’s subsea sector, that the huge potential for fiber-optics sensing in subsea wells and the surrounding infrastructure has become widely recognized.

January 2005 saw initial discussions on the need to raise awareness of the optical sensing potential for widened in-well applications in the upstream industry. Following a year of preparation, a Society of Petroleum Engineers (SPE) Applied Technology Workshop was held in February 2006 in Galveston, Texas. It was titled, “In-well Optical Sensing – Subsea Well Applications – Are We Ready?”

Uptake by 60 to 70 attendees was anticipated for this specialized forum. In the event, more than 130 people took part in an extremely lively educational and entertaining two days. Delegates came from Brazil, Canada, France, Germany, Indonesia, Japan, Norway, United Kingdom and United States.
Educational sessions included covered:
• Types of in-well optical sensing systems commercially available and under development;
• Installation case histories;
• Subsea trees;
• Subsea control systems and subsea infrastructure installations; and
• Subsea well completions.

These session topics and accounts of their impact on the implementation of in-well optical sensing systems gave participants a comprehensive overview of the related challenges in this industry segment.

Issues facing increased usage were explored; technology gaps and other barriers were identified. Subsequent brainstorming led to some good ideas for closing the gaps and overcoming thebarriers. At the closing general discussion, it became apparent that such solutions would require concentrated effort, and there was widespread interest in evaluating the potential for forming a new industry group spearhead.

The resulting “launch” meeting was held in June 2006. Interest levels had intensified so that the new international industry group “SEAFOM” (Subsea Fiber Optics Monitoring) was established to promote the growth of in-well and subsea fiber-optic monitoring installations in subsea applications. Attendees agreed to extend the scope to relevant technical issues for offshore dry tree applications and downhole optical challenges common to onshore as well as offshore wells.

About SEAFOM

SEAFOM is an international joint industry project promoting the growth of fiber-optical sensing in subsea applications. SEAFOM’s vision is to promote the growth of fiber optics in subsea applications. Membership is open to organizations active in developing, interfacing with and deploying in-well and subsea fiber-optic monitoring systems and components. SEAFOM was launched in June 2006 and meets four times a year, alternating between the United States and Europe.

Uptake of SEAFOM membership has been remarkably fast. As of this writing just under 40 companies have signed up. Member organizations span the industry from established operators to new innovative companies. SEAFOM is global in its reach, with members coming from Asia, Australasia, Europe, North America and South America.

What does SEAFOM actually do?

The membership’s common goal of encouraging the increased usage of fiber-optic sensing systems has a range of motives, most driving technological benefits encompassing:

• Unique sensing capabilities;
• Reliability over existing electrical monitoring systems;
• Passivity;
• No electronics downhole;
• No moving parts;
• Ideally suited for harsh environments;
• High-temperature capability;
• Vibration and shock tolerant;
• High data transmission capability;
• Multiple sensors on common fiber infrastructure;
• Technological advances driven by telecom; and
• Multiple sensor types on single fiber (reduced number of penetrations in tubing hangers and downhole packers).

The SEAFOM Charter’s assertion “to facilitate the growth of fiber optics subsea” has become reality through knowledge sharing and technical working group sessions. The challenges of incorporating fiber optics into subsea installations are well known. They include:
• Facilitating a subsea interface;
• Inclusion in umbilicals;
• Field installation;
• Data integration; and
• Development of specific technical solutions, e.g., fiber-optics wet-mate connectors at the subsea tree/tubing hanger level as well as in-well for multistage completions.
These are being considered in detail within SEAFOM, and best practices are ratified by its operator members, in particular through their own vision statements and ongoing association with asset teams.

Knowledge sharing

Knowledge sharing is led by the operators through the sharing of their visions for the future. Knowledge sharing also incorporates presentations from all SEAFOM member companies, including good and bad experiences, new products, and processes and real installation case studies. Recent topics had the theme
of “connectivity” (from in-well sensing points to topsides data delivery) and featured high-speed communications, downhole optical connections, feed-through connections and an overview of fiber-optic rotary joint technology.

Real work is carried out during and between meetings by all members contributing to the technical working groups:
• System integration;
• Technology gaps and barriers;
• Measuring sensor performance;
• Test qualification including instrumentation; and
• Marinization.

SEAFOM’s success is tangible in a final version of the recommended practice document for a “Functional design and test specification for an optical feedthrough system used in Christmas tree installations” currently being distributed for final review by the membership. A similar document is in progress for marinized instrumentation in cases, for example, where either there is no fiber in the subsea umbilical or the step-out distance is too big to accommodate the positioning of the instrumentation on a host platform.

Gaps and barriers

SEAFOM works to advance the uptake of fiber optics by ongoing identification of technology gaps and other barriers to growth, including perceived barriers, and identifying how these can best be addressed by the industry. A new, operator-led initiative started at a recent SEAFOM meeting in Houston is working to establish the first system integration architecture to be fully addressed by the group. This initiative will develop an optimum way to address the gaps and barriers and may include the formation of focused technical joint industry projects. At first glance these architectures may appear simplistic, but as the membership is already seeing, they are anything but and provide a wide range of challenges and potential solutions.

The top technology gaps are identified as:
• Wet/dry mate connectors and penetrators;
• Subsea architecture;
• Reliability;
• Subsea interrogator; and
• Distributed pressure sensing.
Barriers are identified as:
• Lack of standards;
• Installation process;
• Value interpretation; and
• Risk.

The overall SEAFOM group is led by a steering committee, with each member representing one of the six member company constituencies:
• Operators;
• Downhole completions;
• Subsea trees/controls;
• Connectors;
• Fiber-optic sensors; and
• Fiber-optic technology/interrogation units.

SEAFOM is managed by OTM Consulting Ltd., technology management specialists. Taking instruction from the SEAFOM Steering Committee, OTM looks after the membership, meeting organization and facilitation, a dedicated Website (www.seafom.com), promotion of the initiative, and assisting the steering committee with direction- setting. To find out more about SEAFOM please contact the SEAFOM project manager Paul Johnson, paul.johnson@otmnet.com.