American Oil and Gas Reporter - June 2017 - 52

SpecialReport: Offshore & Subsea
Condition and performance monitoring systems provide
critical real-time data to diagnose potential problems, minimize
operating costs, optimize production output and give operators
early warnings of potential failures to prevent unplanned shutdowns. Even a few days of advance notice of an equipment
failure corresponds to saving millions of dollars in lost production
revenues.
Contrasted to the advancements made in condition monitoring
systems that are now common in automotive, aerospace and
other industries, the subsea industry historically had limited advance feedback on the mechanical fitness, electrical condition
and operating performance of rotating machinery placed on the
seafloor. Subsea developments traditionally have sought to
create a large safety margin by "over-engineering" the equipment
needed to produce a field or inject water based on an understanding
of load conditions, failure modes and other contingencies.
Given the designed-in safety margin, the expectation was
that condition monitoring and instrumentation were not required
outside of operational control. However, multiple trends have
come together in recent years to change conventional thinking
about how subsea fields are developed, monitored and operated.
As a result, condition monitoring has come of age quickly for
subsea production.
Focus On Integrity

The first trend is a renewed focus on equipment integrity,
driven by technical failures on offshore projects that have challenged the idea that over-engineering equipment negates the
need for condition monitoring. Many of these failures were
nonstructural, but nevertheless negatively impacted equipment
functionality and this field's production. Root-cause analysis
often reveals early indicators that would have provided advance
warning about declining equipment conditions. Some examples
of such failures are penetrator failures in a subsea control
module, actuator failures and pressure temperature gauge
failures. In each of these examples, there are signs of changes
in equipment performance if the right information is farmed for
insight.
Following some of these equipment failures, an effort was
made to characterize the early warning indicators through a set
of algorithms. The algorithms were developed to harvest information from existing field instrumentation. New highly instrumented equipment was not deployed, but rather expertise in
how equipment wears out was coupled with available field instrumentation to provide a "live" system capable of providing a
near real-time indication of equipment issues.
Using algorithms and automated monitoring ensures that
even subtle changes over a long period are able to be identified.
This harvesting of available field information necessitates that
the company providing the condition monitoring system have a
detailed understanding of how the deployed equipment is
designed, how it operates and how it ultimately can fail.
Another factor behind the industry's increased interest in
52 THE AMERICAN OIL & GAS REPORTER

condition monitoring and instrumentation is the fact that more
operators are embracing a formal policy in which assurances
must be in place at the equipment qualification stage to detect
an equipment failure that can result in a hydrocarbon release.
This goes beyond simple over-engineering to increase wall
thicknesses, add equipment weight or heighten safety factors,
but rather adopts an engineered approach to monitoring critical
systems to establish more rigorous operational control and
deploy richer condition monitoring systems.
Several established information technology companies have
identified the opportunity to capitalize on the increased interest
in asset integrity by developing new solutions based on big
data, the Internet of Things and industrial Ethernet concepts.
The reality, however, is that instrumentation is expensive to
marinize and harden for deepwater deployment, there are limited
amounts of data streams available subsea, and the equipment
deployed subsea is highly specialized. Installing a $10 instrument
in 3,000 meters of water requires a $10,000 wet-mate connector.
This means that while the industrial Ethernet is making
tremendous inroads in improving asset integrity in topsides
equipment and processes, improving asset integrity for subsea
equipment has been about applying detailed know-how regarding
the ways in which subsea equipment operates and wears, identifying early warning indicators of failure events, and then harvesting available instrumentation to populate the algorithms.
Improving Subsea Economics

Economics always have been a driver for subsea technology,
particularly with increasing water depth. Subsea projects
remained viable at the lower oil prices experienced during the
past few years thanks to savvy about how infrastructure was
put in place to produce offshore fields. Historically, subsea
layouts have been designed from three primary perspectives.
Geology, geophysics and drilling would look at well placement
to reach the reservoir; a subsea umbilical, riser and flowline
(SURF) contractor would lay out an architecture for its scope
of the work; and a subsea equipment company then would
design an architecture to optimize placement of subsea trees,
manifolds and other components.
Although this approach was sufficient to accomplish the
core objective of developing an offshore asset, the focus was
not on optimizing the production system as a whole. Often, the
result was a redundancy in umbilical runs and a surplus of
equipment providing similar functionalities. Rationalizing subsea
equipment by eliminating competing architectures between a
SURF contractor and a subsea equipment supplier reduces inefficiencies and optimizes the entire layout.
As an example, integrating the functionality of a pipeline
end termination and a subsea production manifold, and making
the manifold drastically smaller and lighter, means the SURF
scope is less expensive, the equipment is less costly and timeconsuming to produce, and the smaller footprint allows the
American Oil and Gas Reporter - June 2017

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