LOW-CARBON DRILLING SOLUTIONS
Low-carbon technologies
moving from concept
to reality at the rig site
Industry continues to develop new ways to reduce emissions,
not only through engines but also drilling waste, hydraulic ring line
BY STEPHEN WHITFIELD, ASSOCIATE EDITOR
T he oil and gas industry is well aware of the need to adapt
to a low-carbon future. With the push for net-zero grow-
ing more urgent in recent years, the industry is moving
beyond discussing the need for sustainable solutions and toward
the delivery of effective technologies that reduce or eliminate
harmful emissions from drilling operations.

“We’ve seen a big step-change,” said Frank Tollefsen, CEO of
COSL Drilling Europe. “Everybody in our industry recognizes that
we need to operate as sustainably as possible, but there’s been an
increased focus and an increase in pressure from the regulators,
Highlights
Engine management software systems are
helping drilling contractors reduce both
fuel consumption and emissions, both from
onshore and offshore rigs.

Super-capacitors can help distribute power
to a rig’s engine system at faster rates than
a battery energy storage system, further
improving peak shaving capabilities.

Portable treatment units are enabling
drillers to eliminate emissions generated
from supply vessels typically used to
transport drill cuttings waste to shore.

14 from investors and from the public. It’s ever growing, and it only
emphasizes the importance of us delivering sustainable solutions
if we want to be part of the energy mix.”
Many of the low-carbon technologies currently available focus
on reducing Scope 1 emissions, or the emissions that come from
sources directly owned by an organization. Engine management
systems are the main focus of development in this area. A number
of drilling contractors have recently launched systems designed
to improve fuel efficiency by reducing the number of active
engines on their rigs. Further, new technologies in the market
are focused on minimizing the impact of peripheral emitters in a
drilling operation, such as the hydraulic ring line or the transport
and treatment of drill cuttings waste.

Regardless of the system, the priority for drilling contractors
and manufacturers is getting support from customers for wide-
scale adoption, which can be difficult in an industry that’s typi-
cally been slow to accept new technologies. The key to achieving
that adoption is demonstrating their capabilities in the field and
showing companies the value they can provide.

“We’ve had to establish the reliability of these solutions opera-
tionally so that you can get more buy-in,” said Gilles Luca, Senior
Vice President and Chief Operating Officer at Valaris. “You want to
adopt a conservative approach, and that includes carefully bring-
ing in your rig crews and your operators on the journey, and dem-
onstrating to them the sound operational and engineering basis
of these solutions. The best thing to move this forward is to move
slowly but surely, and build a successful operational track record
with these technologies, so that people will have the confidence
and willingness to use them.”
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LOW-CARBON DRILLING SOLUTIONS
COSL Drilling Europe initially installed its Energy Control System on two semisubmersibles in the North Sea, the COSL Promoter
(pictured) and the COSL Innovator . The software monitors the rig’s diesel generators during a given operation and advises
users on the actions likely to require the least amount of power consumption. CO 2 and NOx emissions have fallen by nearly
50% on the two rigs since installation, and the system has since been installed on the COSL Pioneer as well.

Energy Control System
In 2020, after six years of development, COSL Drilling Europe
launched its Energy Control Project, designed to save energy on
COSL rigs operating in the Norwegian North Sea. The project is
primarily centered on reducing fuel usage of engines and gen-
erators on COSL rigs and, subsequently, reducing greenhouse gas
(GHG) emissions.

The main deliverable from the Energy Control Project is the
Energy Control System, an automated software program that
monitors power consumption during a given operation. The sys-
tem advises users on the courses of action likely to require the
least amount of power consumption, estimating the kilowatts
needed, the amount of fuel needed and the subsequent CO2 and
NOx emissions. These estimates are displayed on a dashboard
that users can access from anywhere.

The system is connected to the rig’s control system so it can act
upon its advisory without any input from the rig crew. However,
it also has manual override capabilities for unforeseen circum-
stances, like a weather event where users may need to shut down
more generators than expected.

Torfinn Kalstø, ICT & OT Manager at COSL Drilling Europe, said
the monitoring and advisory capabilities in the Energy Control
System provide essential insights and help maximize efficiency
gains from the rig. “We’re looking to produce the most efficient
kilowatt hours from the generator. This is the whole idea. It’s all
about maintaining high performance and, at the same time, low-
ering the power usage.”
In 2020, COSL Drilling installed the Energy Control System on
two semisubmersibles in the North Sea – the COSL Promoter,
working for Equinor on the Troll field , and COSL Innovator, work-
ing for Chrysaor . The rigs are each powered by six diesel genera-
tors with maximum capacities of 4,800kW . These previously ran
continuously during drilling operations, but pre-installation anal-
ysis showed these generators were rarely used at full capacity.

Running the Energy Control software, COSL Drilling found that
it could shut down, on average, four of the six diesel engines dur-
ing operations.

The company has already seen a significant reduction in fuel
consumption on these rigs. Prior to installation, the rigs averaged
27 tons/day of fuel consumed in Posmoor/ATA mode (where the
rig is running a thruster-assisted mooring control system) and 29
tons/day in full DP3 mode. After installation, COSL Drilling now
sees averages of 14/tons day in Posmoor/ATA mode and 20 tons/
day in DP3 mode. Depending on the operation, the company has
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