(44b) Advanced Monitoring Systems on Existing Deepwater Infrastructure for Intelli-Field

Advanced Monitoring Systems on Existing
Deepwater Infrastructure for Intelli-Fields

David
V. Brower, Alexis D. Brower

Astro
Technology, Inc.

James
A. Memmott, Reza Asgharzadeh Shishivan, John D. Hedengren

Brigham
Young University

AICHE
2014 Spring Meeting

This paper details major successes in deploying advanced sensing systems on
existing subsea structures. Advanced fiber optic sensors are able to measure
strain, temperature, pressure, fatigue, and vibration of risers, flow lines,
trees, and other subsea equipment. In the past, these monitoring systems were
installed top-side during the construction of new flow lines or other subsea
structures and prior to the installation. Installing on existing subsea
structures without shutting down production has a number of challenges. Some of
these challenges include marine growth, sensor designs that are
non-penetrating, ruggedized sensor design for handling and installation,
materials selection, ROV installable devices, and adhesives or clamps that bond
long-term in the deepwater environment. In this environment, it is critical to
have good coupling between the sensor and the measurement. These challenges and
others associated with proactive monitoring systems that predict mechanical
failure, hydrate formation, flow properties, leak detection, and deformation
are included as tasks in the Clear Gulf Joint Industry Project (JIP), an
industrial consortium started in 2010. This collaboration is a partnership
between Astro Technology, NASA, and leading offshore companies to fundamentally
address issues associated with deepwater development and production.

As an example of a recent success, a post
install system on a deepwater flow line in the Gulf of Mexico has provided 6
years of data on a 56 mile tieback line in water depths of 6,750 feet. Shortly
after the installation of the flow line, the electrically transmitted pressure
signals failed at the well-head. An ROV installable clamp was designed to
retrofit the pipeline with fiber optic monitoring sensors that measure the
temperature and pressure inside the pipeline. This clamp-on device was
successfully secured near the well-head. It is expected to provide continuous
measurements over the design life of the flow line.

Tests performed by NASA show improved capabilities
of the sensors to measure tensile stress and fatigue of components. Recent
advances in bonding methods led to more advanced installations currently in use
on two Tension Leg Platforms off the coast of West Africa. While the bonding
strength decreased slightly when compared with dry environment bonding,
laboratory testing shows adequate adhesion and long term service potential. Additional
fatigue evaluation in an accelerated stress test environment confirms that this
new bonding technology will be able to meet design life requirements for
deepwater systems.

The objective of these advanced sensor systems
is to provide data to both validate flow assurance and structural models and
provide real-time sensor data for a new generation of control systems that have
distributed sensors from the well-head to the platform. These Intelli-field
systems are leading to a new approach to proactively monitor and control
operations that are analogous to a central-nervous system. The objective of
this system is to auto-adapt to changing environmental or internal conditions
that may lead to plugging or mechanical damage such as sloshing and slugging,
hydrate build-up, paraffin wax, asphaltenes, vortex induced vibration, and any
other anomalous event. These deepwater sensing systems are designed to be used
on both new and existing infrastructure.