LOW-CARBON DRILLING SOLUTIONS
Left: Nabors’ SmartPOWER Advisory System incorporates data from several data points, including coolant temperature and
fi lter status within the engine, to advise drillers on the optimal number of engines needed to run a given operation on the rig.

Right: The Canrig PowerFLOW system, set to launch in Q2 2022, uses super-capacitors (pictured) to store and distribute power
immediately to a rig’s engines to minimize the load spikes seen during tripping operations.

conventional process of shipping the waste to shore for treatment
and disposal, eliminating a notable source of emissions from a
drilling operation.

The system works by feeding drilling cuttings into a feed
hopper. Those cuttings are then transferred to a heat exchanger
module for treatment. Inside the heat exchanger module, the drill
cuttings remain in constant contact with the heated internal
surface area to ensure that consistent results on waste separation
is achieved .

A condensation module recovers the heavier phase of the oil,
which is then returned to the mud system. The steam conden-
sation within the condensation module is then transported to a
water treatment module, which recovers the lighter phase of oil.

The recovered water is then discharged from the rig.

The iNOVaTHERM system eliminates the drive module found
in a conventional frictionally heated waste-processing system,
with the power going directly into the high-efficiency heat
exchanger. Gordon Duthie, Senior Director of Sales – Eastern
Hemisphere at NOV, said this feature reduces the footprint and
helps conserve power and emissions on the rig, since the rig
does not need to supply power to the gearbox, rotor and hammers
found in typical friction-based systems.

However, the biggest savings with emissions comes from
eliminating the supply vessels typically used to transport cut-
tings waste from the rig site to the shore, and the trucks needed
to transport the cuttings waste from the vessel to the onshore
treatment facility.

“The treatment at the source really eliminates many of the
logistical challenges that come from operating in a remote loca-
tion, whether that’s on land or offshore. Any conventional waste
handling requires you to use a supply vessel to go out to the rig
and take back the containers of cuttings. From a carbon footprint
reduction standpoint, this system eliminates the need for all that
activity, and we’re eliminating the need for onshore processing
and disposal in a land fill,” Mr Duthie said.

18 The numbers from NOV’s project scenario data illustrate the
emissions savings that are possible from utilizing the system
on the rig site. Comparing the emissions generated against con-
ventional containment and waste-processing methods, iNOVa-
THERM eliminates the supply vessels used offshore and the
trucks used onshore to transport the waste to the treatment facil-
ity, as well as the onshore treatment and disposal operations. In
this project scenario, a significant amount in emissions (280,264
kg of CO2 per drilling campaign) was saved by treating the drilling
wastes on site. Overall, the conventional method created 319,063
kg of CO2 emissions and 4,720 kg of NOx emissions. With the
iNOVaTHERM system, those figures went down to 186,436 kg of
CO2 and 3,107 kg of NOx.

“These numbers demonstrate that processing drilling wastes
offshore goes a long way towards meeting the emission reduction
goals and targets our clients have committed to. Once we start
eliminating the supply vessel and the other logistics with onshore
processing, there are significant environmental and cost savings
to be had ,” Mr Duthie said.

The technology was launched commercially in January 2021
in the UK sector of the North Sea following 18 months of develop-
ment and testing at NOV’s thermal treatment plant in Aberdeen .

It has since been used by two major oil and gas operators on four
drilling campaigns in the North Sea. A fourth campaign began in
April 2022.

Boosting hydraulic pump efficiency
Another erratic power consumer on the rig is the hydraulic ring
line. This system feeds several pieces of hydraulic equipment on
the rig, including iron roughnecks, power casing tongs, vertical
column pipe rackers and catwalk machines. The flow and pressure
in the ring line system are usually set to a level that can accommo-
date simultaneous operation of these pieces of equipment.

Richard Verhoef, Product Line Manager for Handling Tools
at NOV, compared the hydraulic pumps powering the ring line
M AY/J U N E 202 2 • D R I L L I N G C O N T R AC T O R



LOW-CARBON DRILLING SOLUTIONS
Left: NOV’s Eco Booster system, launched last year, contains an accumulator skid (pictured) that stores and distributes power
to the hydraulic pumps powering a rig’s ring line system, reducing power usage during periods of peak demand. Right: NOV’s
iNOVaTHERM, a portable unit for treating and disposing of drilling waste on the rig, has been used on four drilling campaigns
in the North Sea since its commercial launch in January 2021.

system to generator sets. To deal with the potential hydraulic
demands at peak usage, more pumps are running than what is
really needed for a large percentage of the time. Pumps running
idle for 24 hours a day consume a large amount of electricity and
fuel, continuously emitting CO2 and NOx. However, the pumps
need to be able to handle sudden increases in flow requirements
when the hydraulic pump is activated. Hydraulic equipment
already in operation will also be affected by this pressure drop.

To help operators use their hydraulic pumps more efficiently,
thereby reducing power usage and emissions, NOV launched its
Eco Booster system last year. Eco Booster is a hydraulic energy
storage system that optimizes hydraulic ring line performance
by storing hydraulic power when demand is low and releasing
hydraulic power when demand is high. When additional flow
is required, the technology transfers hydraulic energy from the
accumulators, limiting the need for additional hydraulic pumps
to start up.

“This system basically eliminates that pressure drop. Instead
of having the pumps increase their RPM to boost the pressure
in the system, Eco Booster provides that short peak of hydraulic
power. Instead of having all of your pumps running all of the
time, you can reduce the number of motors and pumps that
are running. That’s where the power usage savings come from.

That’s where the emissions savings come from,” Mr Verhoef
said. The technology is made up of an accumulator skid with four
nitrogen pre-charged accumulators, a booster skid and an auto-
mated control system. The accumulator is charged by a pressure
booster when the ring line flow consumption is low.

When charged, the accumulator matches the flow require-
ments and demands of the equipment, even when those require-
ments and demands exceed the ring line pump’s capacity. The
accumulator also stores power during periods of light loading
on the hydraulic equipment – a process known as load leveling
– leading to more optimal use of the hydraulic pumps. The Eco
Booster also dampens the variations caused by sudden power
demands, providing instant flow and pressure to the ring line.

NOV estimated the savings it could generate from the Eco
Booster based on historical power usage data. A rig typically runs
six hydraulic pumps 24 hours a day , with each pump consuming
55 kW of power each day. Each pump burns an average of 0.2875
liter/kW used, and NOV calculated 3.23 kg of CO2 and 4.2 g of NOx
emitted for every liter of fuel burned on the rig.

With the Eco Booster system installed, a rig can potentially
run on four generators 65% of the time it is in operation. Over the
course of an entire year, this would mean annual fuel savings of
180,072 liters. Emissions-wise, that annual fuel savings would
lead to 581 tons of CO2 saved and 756 kg of NOx savings per year.

Some countries already impose taxes on CO2 and NOx emis-
sions, resulting in an even higher operational cost to the rigs oper-
ating in those areas. Even if the system is used in an area without
emissions taxes, Mr Verhoef noted that operators can make up
the cost of installation in a few years. “If you’re saving tens of
thousands a year in fuel costs, this system becomes a relatively
small investment for the customer with a pretty good return on
investment. The more pumps you can put offline, the better the
savings, and the more stable the hydraulic system is, the better
you are with emissions.”
Since its commercial launch in 2021, the Eco Booster system
has been installed on one rig for a major operator in the North Sea.

Mr Verhoef said NOV has commitments to install four additional
units for separate operators later this year. DC
D R I L L I N G C O N T R AC T O R • M AY/J U N E 202 2
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