WELL CONTROL READINESS
Figure 2 (above): The BOP Reliability Systems Soak Test dashboard uses pressure
trend identification algorithm technology, which in this case identified a leak in the
subsea manifold regulator fluid circuit within a minute of function actuation. Figure
3 (right): Upon visual inspection, confirmation was made identifying an SPM valve
with a failed seal plate while at maximum operating pressure.
annual reports, the cumulative average
BOP pulls hovered around the low 30s
annually for the represented BOP stacks.
It’s clear there is a marked improvement in
these figures when juxtaposed with data
from preceding years.
Data from 2020 and 2021 present an
even more encouraging narrative: The
number of stack pulls averaged in the low
20s. Many BOP experts acknowledge the
pivotal role of the rigorous soak tests con-
ducted prior to deployment. Although this
isn’t a normalized metric, it points toward
enhanced reliability performance.
The inference? The industry is lean-
ing into the lessons learned and making
strides in equipment reliability perfor-
mance. Considering this positive trend,
coupled with industrywide knowledge
sharing, there has been clear progress in
the pursuit of zero NPT.
State of industry practices
Current industry practices regarding
BOP soak testing exhibit significant varia-
tions in frequency, methodology and test
duration. Many equipment owners and
operators conduct these tests regularly
22 before deployment, while others perform
them both before and after deployment.
Additionally, there’s no standardized time-
frame for these tests, with durations rang-
ing from minutes to days.
The complexity of these tests also varies,
from two-step tests to procedures with 15 or
more steps. Factors influencing the testing
methodology include stack configuration,
contractual agreements, deployment dura-
tion estimates, maintenance planning, con-
dition-based maintenance program matu-
rity, crew proficiency and digital monitor-
ing capabilities. Despite these differences,
“boots-on-the-ground” inspections remain
the most common means of leak detection.
There is also significant promise shown
in the latest digital trend recognition algo-
rithms. For example, a proactive subsea
team, along with a specialized team of
remote BOP analysts, have been able to
identify system anomalies within min-
utes of pressure stabilization and pinpoint
critical components within each fluid cir-
cuit (Figures 2-4). This can significantly
reduce troubleshooting and fault-finding
efforts during an already stressful, fast-
paced pre-deployment period.
Standardization challenges
Differences in BOP design and opera-
tional philosophies among major OEMs
also contribute to variations in soak test-
ing practices. Each OEM has testing proce-
dures tailored to their BOP designs, leading
to a wide array of testing methodologies.
For instance, OEMs have freedom regard-
ing the rated pressure of the operating
chambers in their BOPs. These rated pres-
sures can vary from a few hundred psi up
to 5,000 psi or more. The soak tests must
accommodate these differences that exist
not only between different OEMs but also
in different models of operators within
each OEM.
SEPTEMBER/OCTOBER 2023 • DRILLING CONTRACTOR
WELL CONTROL READINESS
An example involves hydraulic wellbore
connectors. Some connectors should not
be locked with pressure exceeding 1,500
psi due to crushing effects that may be
imposed on the wellhead, BOP mandrel or
test stump. There are others that physical-
ly cannot be latched above a specified psi
because a relief valve has been installed
on the closing circuit.
Testing should also take into account
the OEMs’ allowable return flow for control
system valves. This has been discussed in
API Standard 53 committee meetings for
potential inclusion in the next revision
of the standard. Normal return rates have
been reduced by design improvements
(e.g., highly polished tungsten seal sur-
faces versus matte finishes on softer mate-
rials). Control system OEMs may produce
new designs that would lead to tighter
systems with less return flow.
Potential to reshape with
technology Collaboration and digitalization can
play a pivotal role in standardizing BOP
soak testing practices. By working togeth-
er within the API committee meeting
structure, operators, contractors and ser-
vice providers can develop a unified test-
ing methodology and recommended best
practices that consider the different BOP
configurations and unique requirements
throughout the industry. Digital tools can
streamline this process, making it easier
to apply uniform testing protocols across
various operations and regions.
In addition, digital applications can
be designed to perform trend analyses,
remove subjectivity from test results, and
help identify testing missteps (e.g., valve
alignment and trapped pressure in the
wellbore). Digital twin displays can facili-
tate collaboration and provide insights for
the stakeholders as they strive to protect
people, the environment and assets.
Standardization framework
Given the history of control system
failures, the industry has recognized the
need for enhanced testing measures, par-
ticularly in soak testing. Drilling contrac-
tors have been refining procedures and
monitoring techniques. This initiative
aligns with the specifications set out in
the 5th edition of API Standard 53 from
Figure 4: In same time frame as Figures 2 and 3. Utilizing client-specified system
pressure leak-off rate criteria, a passed test was seen after about 40 minutes.
December 2018. This edition introduced
the requirement for soak testing subsea
stacks prior to deployment. Specifically,
Table C7 emphasizes the need to validate
the BOP stack hydraulic circuits at the
highest pressures anticipated during well
control operations. The test’s duration is
per the equipment owner’s stipulations,
with the key acceptance criterion being a
visual confirmation of no leaks.
Standardized BOP soak testing should
encompass all aspects of the pre-deploy-
ment soak testing process, including test
step duration, pressure limitations, con-
figuration (mode) and testing conditions.
It should also consider the varying envi-
ronmental conditions in which BOPs are
deployed, as well as the different types of
BOPs and their specific requirements.
Path forward
The contributors of this article support
the development of standardized recom-
mendations for BOP soak testing for inclu-
sion in the next edition of API Standard 53.
This could be an informative annex that
will help reduce subjectivity in visual leak
verifications, leading to enhanced safety
and reliability performance industrywide.
Equipment owners would have the benefit
of shared best practices as a starting point
for their procedures.
Improving the effectiveness of pre-
deployment soak testing of BOP systems
will reduce risks directly associated with
its reduced availability to perform the
intended critical functions. In addition,
reducing unplanned BOP pulls will elimi-
nate risks associated with retrieval and
subsequent redeployment. This further
safeguards people and the environment.
A joint effort among stakeholders in
crafting this methodology will enable swift
and effective BOP assessments and stable
health KPIs, and further reduce subsea
NPT. The journey to improve the reliability
and performance in drilling operations
will not cease as we reaffirm our commit-
ment to improving industry standards of
performance and safety. DC
Reference: American Bureau of Shipping &
ABSG Consulting Inc’s Blowout Preventer (BOP)
Maintenance and Inspection Study Final Report
for the Bureau of Safety and Environmental
Enforcement., June 2013.
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