WELL CONTROL READINESS
Standardizing subsea BOP soak
testing: overview of value and
recommended best practices
Proposal for API Standard 53 annex aims to unify
testing methodology while considering different
BOP configurations, potential for digital tools
BY PATRICK HILLARD AND LEONARD CHILDERS, IPT GLOBAL;
AND AHMED OMAR, SEADRILL
The BOP soak test is an important yet
often misunderstood part of deployment
preparation for subsea BOPs. Although it
helps improve both the safety and efficien-
cy of drilling operations, this test remains
an area lacking industry standardization,
leading to potential uncertainties and
inconsistencies in BOP performance. This
article explores the history, challenges and
potential to standardize an often-over-
looked contributor to well control equip-
ment reliability.

The well control equipment
evolution The first BOPs were sketched out by
James Abercrombie and Harry Cameron
on a sawdust-covered machine shop floor
just east of downtown Houston in the early
1920s. Since then, the industry has come
a long way. State-of-the-art equipment is
used to set wellheads more than 10,000
ft below the water line, deploy, latch and
remotely operate multiplex subsea BOPs,
and then drill into ultra-deep, high-pres-
sure hydrocarbon reservoirs.

To safely accomplish these engineer-
ing breakthroughs, rigorous verification
requirements such as pressure testing,
function testing, manufacturing specifica-
tions, maintenance protocols and kick/
leak-off detection methodologies have
been developed. These standards have
regularly been adopted by state and fed-
eral regulators and incorporated into API
Standards and/or the Code of Federal
Regulations, in the context of subsea BOPs
and subsea BOP control systems.

BOP soak test value
The BOP soak test involves detailed
evaluation of the multiplex electro/
hydraulic circuitry in both the primary
and secondary control systems of the BOP.

It applies a predetermined pressure to
various operators and fluid circuitry for a
required duration. During this test, subsea
engineers meticulously inspect the BOP
for visible leaks, weeps, drips, fogging and
other indicators that inform necessary
maintenance before deployment. In many
instances, digital monitoring and pressure
signal analysis are performed concurrent-
ly to expedite the soak testing process and
mitigate the need for extended trouble-
shooting iterations.

A robust soak test prior to subsea deploy-
ment provides an essential assessment of
the health of the BOP. It provides crucial
insights into the BOP stack’s fitness for
service by identifying potential issues that
could affect its performance and availabil-
ity once deployed. By physically inspecting
the BOP and analyzing the stabilized pres-
sure readings over a brief period, trained
personnel can identify leaks or potential
component degradation within each pres-
surized fluid circuit. This not only facili-
tates troubleshooting and smarter mainte-
nance efforts but also offers stakeholders
peace of mind by ensuring due diligence
has been accomplished to protect person-
nel, the environment and related assets.

While soak testing remains the fore-
most method to assess control system
health before deployment, it’s imperative
to understand the inherent limitations.

Soak tests can’t replicate the multifaceted,
real-world conditions a BOP would face
when placed on a wellhead. These factors,
such as stack movement (both tension and
compression), fluctuating temperatures
and varying hydrostatic pressures, can
significantly impact system performance.

Recognizing these challenges, some BOP
owners have pioneered innovative testing
procedures. One such approach involves
placing the stack under tension during
surface testing, simulating the separation
forces encountered at interface connec-
tions. This method has proven beneficial,
unveiling issues related to the design of
specific seals. Moreover, these insights
have inspired the development of designs
that are better equipped to handle such
dynamic movement, ensuring enhanced
reliability and operational efficiency.

Thus, while current testing methodolo-
gies provide valuable insights, it’s impor-
tant to continually evolve, capturing the
nuances of real-world operations in the
form of recommended best practices.

Recent industry performance
data Technological advancements have
prompted industry experts and regula-
tors to develop stricter requirements for
equipment verification. These improve-
ments reflect a deeper understanding of
the industry’s increasingly complex equip-
ment, enabling refinement of testing pro-
tocols to ensure they are fit for purpose.

Historical data presents some signifi-
cant findings. As outlined in the BSEE-
sanctioned report, “Blowout Preventer
(BOP) Maintenance and Inspection Study
by the American Bureau of Shipping and
ABSG Consulting Inc. (2013),” 61% of sub-
sea BOP system failures were linked to
the control system. Notably, the blue and
yellow control PODs, along with the sur-
face MUX control system, accounted for
over half of these failures. The study’s
mean time to failure revealed an average
of 48 days of operation between compo-
nent failures. It’s crucial to note that due
to built-in system redundancies, some of
these recorded failures signaled the need
for upcoming repairs rather than indicat-
ing a stack pull.

Fast-forward to the current era, where
detailed defect data is available from the
Rapid-S53 database. In the 2018 and 2019
DRILLING CONTRACTOR • SEPTEMBER/OCTOBER 2023
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