I wrote about
decarbonizing drilling operations in my 2022 book Natural Gas and Decarbonization.
I will post some excerpts here. I also attended an informative World Oil
webcast on the subject in November 2023. In my book, I covered new decarbonized options
from oilfield service companies for hydraulic fracturing and drilling, some of
which are quite similar such as the use of aeroderivative turbines,
reciprocating gas engines, gas blending engines, diesel-electric hybrids, and
smart power management systems. E-fracking is now well established as is
E-drilling. Utilizing several of these solutions together can optimize power consumption,
reduce emissions, and save money over conventional diesel systems. Added
together, the emissions reductions can be quite significant.
Notes from World Oil’s Webcast of Decarbonizing
Drilling Ops
The following sections
are from my webcast notes. The drilling rig technology provider company
CanRig is owned by drilling contractor Nabors. CanRig’s offerings include
advanced robotics for several rig functions, electric-powered top drives, power
and engine management, energy storage, rig lighting systems (Illumic), and fuel
enhancers like NanO2 that optimize diesel engines.
Combustion Catalyst Fuel Enhancers
Fuel enhancers
typically reduce diesel fuel emissions by 4-8% according to tests. While this
is not groundbreaking it is helpful. One product, NanO2 combustion catalyst
fuel enhancer, available to any drilling rig, reduces combustion temps. It can be
added through automated dosage 750-to-1 diesel-to-NanO2. It can be done
manually as well. Instrumentation and recording can track savings, determining the amount
of fuel burned and the amount of work done in KWh/gallon (KPI) –typically 4-8% savings
in fuel consumption. Includes C-tane booster octane booster, cleaner, and
combustion catalyst (brings extra O2, its most unique feature). It ignites
earlier and more O2 gets into the combustion cycle so peak T & P drop = large
NOx reduction. Another option for fuel enhancement is hydrogen injection which works
differently than NanO2 but also reduces emissions. Utilizing H2 from
electrolysis (green hydrogen) would reduce emissions further. Offshore ops
typically use more power than land ops so fuel enhancers can provide more
emissions reduction when used in offshore ops.
Smart Power Management and Integrating Energy
Storage in Hybrid Systems
Smart power
management is a key feature of electric systems and fuel-electric hybrid
systems. These Advisory and Control systems can also utilize AI/machine learning
for optimizing power consumption. Pump ramping can switch from 3 to 4
generators when necessary (control portion). These systems also reduce manpower,
with no generator swapping needed. The driller can do it from his chair. Nabors
did an Eagleford Shale study in Texas. Results include saving 4.7% in fuel vs.
full utilization and 4.1% vs. manual optimization, 17% reduction in engine run
time, and 91 metric tons of CO2 abated. Integrating energy storage can replace and
reduce diesel consumption. Energy storage can be optimized to provide peak
shaving. Knowledge of power demand in drilling can be used to optimize – energy
storage can shave peaks instead of adding a generator. Seamlessly changing from
generators to storage is a feature. Work is ongoing to better monitor emissions
all around the rig system. AI is better than a reactive system. AI can analyze
and react to changes in power in real time. Pairing AI with automation is key
to smart power optimization. Patterson-UTI’s EcoCell power management system is
examined later in this article.
New LED Rig Lighting Systems – CanRig’s ILLUMIC
CanRig’s ILLUMIC Lighting System is a new LED-based system that is crown-mounted and lights an entire
location. Fuel costs and emissions are reduced. It does not use inefficient
small generators as diesel light plants do. 233KWh saved per year per rig –
small but significant. LED lights with a 10-year lifespan, maintenance-free, and no
noise. Easy on-off. It saves about 29 gallons of fuel per day. Better lighting throughout
the location is provided. There are installation costs but minimal opex and
almost zero downtime. Illumic can take time. It is set up on rig moves. Power
Tap requires some offline time. It takes experience to do it quickly. It costs
more to set up but still overall cost savings are desired – breakeven or
better. Nabors website elaborates a little on the ILLUMIC system:
“The ILLUMIC lighting system reduces noise, CO2
emissions, costs and man-hours related to relocating and maintaining multiple
portable light towers on location.”
“ILLUMIC offers more reach and foot candles per square
foot than any other conventional system, replacing an equivalent of up to six
diesel light towers on-site. Our engineers designed a frame that does not
impact the crown’s footprint.”
Plugging Directly into Grid Power
Plugging the rig
into the grid means there are no generators or diesel onsite with much lower emissions
and noise. Reliable optimum rig power is provided. Access to utility power is
enabled with a high-voltage cable reel, switch gear for power compatibility, a power
tap skid, and a mounted substation transformer. Another option is to bury cable
across a location. A harmonic filtering unit can help with power balancing.
Usually, 3-4MW of power is needed for drilling ops. 4MW rated transformer is
common. Voltage up to 33kV can be accommodated and with 22 modules installed
there is a 440mt CO2 abate per unit per day. 2 units have been deployed to
Argentina, presumably in the prolific Vaca Muerta shale play in the Nequin Basin.
In terms of performance
evaluation and emissions reduction evaluation, Scope 1 emissions go to Scope 2, and
grid power is about 50% less emissions intense/more efficient. There can be 70%
cost reductions due to high diesel prices. Hess began doing this in the Bakken play
in North Dakota and apparently, now all of their rigs use it. If there is a
power outage there would be a need to bring generators online so some need to
be available as backup. Work is ongoing to make such a change seamless.
The following sections
are excepted from my book, Natural Gas and Decarbonization. These were written
in early 2022 so mostly still relevant. I also include a section on data analytics
in the drilling sector:
Caterpillar’s Dynamic Gas Blending Engines: The 3512E
Caterpillar’s dynamic
gas blending engines are dual-fuel models that blend natural gas and diesel.
They can run on different fuel sources “including CNG, LNG, pipeline gas and
even field gas as an alternative to flaring. With Cat DGB engines, you could
cut your diesel consumption by as much as 85%, while maintaining all the power,
reliability and ease of maintenance of our diesel models.” The latest
model, the 3512E Dynamic Gas Blending Well Service Engine, maximizes natural
gas burn and can run on up to 85% natural gas. It is based on their diesel
engine platform. Current field tests indicate that 70-75% diesel displacement is
commonly achieved. That is significant fuel savings and significant
decarbonization. The 3512E is the first dynamic gas blending engine to achieve
EPA Tier 4 emissions of near zero NOx and particulate matter.[1]
{On their website now Caterpillar lists in their section
on Land Drilling Engines and Generator Sets the EPA Tier 4 compliant C32 ACERT
model shown below}.[2]
Caterpillar’s
C32 ACERT EPA Tier 4 Engine
EcoCell: An Energy Management System for Optimizing
Generator Use in Drilling Ops with Battery Storage
The EcoCell
optimizes the number of generators online and keeps them in their most
efficient power-to-emissions ratio range. It uses strategic deployment of
battery storage to do this. It can be deployed during a rig move or rig walk.
In a four-generator array, the energy storage system is deployed to replace
the 4th generator. It automatically stops and starts generators
according to rig power demand and state of charge of the batteries. It can be optimized by charging when loads are low during certain drilling functions and by
discharging when loads are high to make power. It discharges while the mud
pumps are running and charges during the making of a connection when the pumps
are off. Emissions can be especially lowered during tripping. Temporary or
transient high load demand during hoisting requires two generators. EcoCell is
capable of discharging at a rate more than that of 1.5 generators so only
one generator needs to be used for tripping out of the hole. A case study was
done with EcoCell on four units deployed for over a month. Based on the results
the emissions reductions varied between 6 and 25% with the rig fleet average at
15.7%. Only one was deployed in a four-generator array and that one had the
highest emissions reductions at 24.8%. The active rig fleet, presumably of
Patterson-UTI, is at 89 with 34 rigs operating 4 generators and 55 rigs
operating 3 generators. Thus, the biggest emissions advantage (24.8%) is when
the EcoCell replaces the 4th generator in a four-generator array.
Over the whole fleet, it is still over 15% and that is a significant emissions
reduction. This is another example of electrification and digitalization hybridizing
with thermal operations for efficiency gain.[3]
Data Analytics and Digital
Automation in the Drilling Sector
It is now widely
acknowledged that machines can be more efficient and thorough in data-heavy parts
of processes. This machine learning can optimize processes by automating assessments
and adjustments during operation. Human programmers can tweak the processes
based on what is learned. For oil and gas, the use of data analytics and
digital automation is being used more and more in the production, processing,
and refining sectors. More recently, it is being tested and deployed in the
drilling of wells. Although electronic and automated functions in drilling are
not new, they are now getting much more detailed. Machine learning is being optimized
and deployed.
Oilfield
services company Schlumberger reported in August 2021 on their Automated
Directional Drilling tool tests in the Middle East and in the Permian Basin. The
launch on August 17 describes the tool as an “intelligent and dynamic
downhole automated control system that instantly interprets and acts on data.”
Since I am hyper-aware of the likely possibilities and limitations of this
technology due to my work as a geologist interpreting wellbore geology, I am
both intrigued and skeptical. It certainly has merits for drilling and will
likely get better as time goes on. Certain geologic conditions, especially of structurally
flat areas, will favor its use. More complex geology will likely be far more be
more challenging. Some geosteering software companies are working on automated
geosteering algorithms and these may well be helpful once they are fine-tuned.
Schlumberger’s system reduces data-to-surface transmissions or downlinking data
to and from the rotary steerable drilling system. The three apps of the tech
are given as auto-vertical, auto-tangent, and auto-curve. The Middle East tests
drilled the curve sections (auto-curve) increasing drilling rate of penetration
(ROP) by 37% and 39%. In the Permian tests the Automated drilling system was
used in the curve and lateral sections for 7 wells resulting in 39% increase in
ROP. Those are pretty good numbers but I’m guessing it will be some time before
automated drilling becomes widely adopted. The tech also claims better
wellbores, presumably with less doglegs or kinks in the hole.[4]
Canadian
drilling information and data company Pason has been utilizing their DAS system
for automated downhole control of weight-on-bit (WOB) and rotary RPMs. Instead
of keeping those parameters constant the tech allows them to be adaptive to the
rocks based on their algorithms and software licensed from ExxonMobil. They
tout faster drilling, less drilling assembly trips, and improved wellbore
stability. “The system continually evaluates bit-to-rock interaction using a
combination of rate of penetration (ROP) and mechanical specific energy (MSE).
MSE is a measure of the amount of energy being used to destroy a unit of rock.
Minimal MSE is considered optimal as an indirect measure of difficult
vibrations to detect on the surface.” The tech has been used on hundreds of
rigs and a couple thousand wells, mostly in North America, since 2018.[5]
The human element in the system is simply to set the parameter limits. The
drilling system utilizes a close loop system between the autodriller and the
top drive. The goal is to “build and follow a parameter limit roadmap.” The
roadmap should integrate WOB, RPM, differential pressure, torque, and SPP. The
tech works best in homogenous rock. Some known sections of rock may be too
heterogeneous so in those cases the system can be disconnected. The system also
has the ability to mitigate known drilling dysfunctions. Known drilling
dysfunctions that can be automatically mitigated include stick-slip, formation
stringers, motor stalling, and lateral vibration. Tests of the system in the
Bakken indicate they can increase ROP and decrease drilling days up to 30%
although, for the average of deployments, they suggest ROP improvement between 7 and
17.5%.[6] Constantly,
setting and adjusting the parameters to account for changes in the rocks, or
lithology, especially during the vertical and curve sections, is needed as well
as other optimizations of human adjustments into the system.[7]
Automated
slide drilling, where the drilling rotary table is not spinning but the drill
string is sliding the bent drilling motor to make angle adjustments, often
based on geology, is also being utilized more. Drillers can develop “drilling
recipes” for different rock formations in different basins. These recipes take
into account wellbore geometry, planned bottom-hole assembly, planned drilling
parameters, and measured depth. Automated drilling systems are still being
tweaked but will likely improve more through time. ROP improvements of
automated slide drilling over manual slide drilling are already occurring.[8]
Other
companies like National Oilwell Varco and its M/D Totco business unit with its
NOV Wellbore Technologies, have long been involved in similarly automating
drilling systems. They started in 2012 and introduced their NOVOS software in
2016. They address the same issues as the Pason system like known drilling
dysfunctions and bit-and-rock interactions. They mention some challenges in
process automation for drilling as: “aligning goals and expectations prior
to deployment, accounting for human factors, and measuring utilization and
performance to foster an iterative and agile approach to for improvements.”
I think that learning and knowing how and when to set and reset parameters for
each basin and area will remain challenging but also yield rewards. NOV
developed a process automation platform that can automate drilling sequences.
Its platform can also accept new apps. Faster weight-to-weight times, or times
between drilling, connecting another length of pipes, and getting back to
drilling, have been decreased by up to 30%. NOV is currently developing an autonomous
drilling system, NOVOS 4, that can be used with scheduled drilling activities
like tripping or reaming, as well as drilling.[9]
Another data
analytics innovation being used oil and gas is the closed-loop digital twin.
Digital twinning refers to a process where operational data is analyzed and fed
back into the system for adjustment. It bridges planning models and parameters
with real-time digital models and parameters. This has many applications in
many industries and is an important part of data analytics and machine
learning. Process optimization is the goal. Digital twinning requires digital
interoperability so that platforms and systems are compatible. GIS, CAD, and
IoT apps can be integrated with digital twins. Oilfield services company Baker
Hughes has been using digital twins to better understand and predict drilling
fluids' rheology properties and transport of drill cuttings up the hole. Such
understanding is useful for ensuring healthy hole conditions and preventing
problems like lost circulation of fluids and stuck pipe, especially in high-pressure, high-temperature drilling environments. Predictive models based on
machine learning can also optimize hole cleaning, an important part of the
function of drilling fluids in successful drilling. Baker Hughes developed a computation
flow dynamics model for their study. In the future, they hope to build digital
twins and closed-loop optimization systems for ROP optimization and
transmission of hydraulic horsepower to the bit.[10]
Maersk’s Retrofitted Battery-Diesel Hybrid Offshore
Drilling Rigs
In November 2020
Maersk deployed its first low-emissions rig, the Maersk Intrepid, for Equinor
in the North Sea offshore Norway. The Intrepid is an ultra-harsh environment
CJ70 jack-up rig. The low-emissions features are of three types: 1) hybrid
power which utilizes battery storage to address the variable power and high
peak loads of rigs and increase efficiency. Braking energy can also be recovered
which also increases efficiency, as it does in hybrid automobile engines, 2) Energy
Emissions Efficiency software – this digital energy management system optimizes
rig energy use, and 3) Selective catalytic reduction (SCR) to reduce NOx
emissions. The diesel-battery hybrid reduced fuel use significantly and dropped
emissions by 25% in the first test. It also offers a 95% total reduction in NOx
emissions. A second rig, The Maersk Integrator, began drilling in 2021. These
are not new rigs but retrofits. The project involves an agreement between
Maersk and Equinor and funding from Norway’s NOx Fund which wants to fund more
similar offshore rig retrofits. They are also exploring running hybrid rigs
with shore power which will further reduce emissions. The rigs utilize Siemens
BlueVault lithium-ion battery storage system, tailored for offshore vessels.
Siemens suggests that 300 of the world’s 500 ultra-harsh environment jack-up
rigs can be retrofitted.[11] [12]
Nabors’ Robotic Drilling Rig
In partnership
with ExxonMobil subsidiary XTO, Nabors launched the Pace-R robotic drilling rig
in the Permian Basin in August 2021. The technology has been developed over the
past five years. Nabors acquired the company Robotic Drilling Systems in 2017.
Nabors utilizes Canrig Drilling Technology as a subsidiary to provide system
components like automated torquing, automated top drive, casing drive system to
run and make-up casing, automated catwalks, robotic pipe handler, automated
racker, electric drill floor robot, electronic robotic roughneck, elevator, draw
works, and control systems. Increases in drilling efficiency, worker safety,
and reduced emissions due to electrification, are expected results of the new
rig.[13] [14]
On-Site Drilling Waste Processing: TCC Rotomill Drill
Cuttings Treatment
On-site
drilling waste processing and recycling has the potential to decrease trucked
off waste by up to 95%. Most drilling mud system treatments are currently done
offsite. UK-headquartered drilling waste management company TWMA has developed
a drilling mud and drill cuttings on-site processing solution that can decrease
the carbon footprint of these ops by 50%. The TCC Rotomill drill cuttings
treatment system “uses a process of thermal desorption to separate drill
cuttings and associated materials into their three constituent parts – oil,
water and solids – for recycling and reuse.” The skid-mounted units can be
operated with a diesel engine or an electric motor. In oil-based drilling mud
systems they can recover higher percentages of base oil. “The outputs from
the TCC RotoMill are well below environmental legislation thresholds, enabling
for safe disposal at source with the technology.” “Recovered solids and
water meet local regulations and can be disposed of at source. Oil recovered in
the process can be reused in the drilling system. Carbon footprint is reduced
by 50% due to the elimination of transport to offsite treatment facility.” TWMA
is expected to present results in a technical paper at a session of the 2021 ADIPEC
oil and gas conference in the UAE hosted by the Society of Petroleum Engineers
(SPE). The paper was co-authored by DNV. The process has long been employed in
the UAE. TWMA is also active in the US, Egypt, Norway and Africa. They will
also unveil a new real-time drilling waste operations monitoring platform with
hardware and software that automates part of the process.[15] [16]
References:
Practical
Solutions to Decarbonizing Drilling Operations. World Oil, Webcast. November 8.
2023.
Scaling
Up to Decarbonize Offshore Operations. Purify Fuel. April 30, 2023. Scaling
Up to Decarbonize Offshore Operations | Purify Fuels
Energy
Efficient Lighting Solution. Nabors. Energy
Efficient Lighting Solution - Nabors
EcoCell Hybrid Battery Energy. Patterson-UTI. Sustainable Solutions - EcoCell - OneSheeter - Version1.indd (patenergy.com)
[1]
3512E DYNAMIC GAS BLENDING™ WELL SERVICE ENGINE. Caterpillar. 3512E
Dynamic Gas Blending Engine | Cat | Caterpillar
[2]
Land Drilling Engines and Generator Sets. Caterpillar. C32
ACERT™ Land Drilling Engines and Generator Sets | Cat | Caterpillar
[3]
E&P Case Study: A New Tool to Reduce Emissions from Drilling Operations.
Patterson -UTI Energy. Hart’s E&P Magazine. E&P
Case Study: A New Tool to Reduce Emissions from Drilling Operations | Hart
Energy
[4]
Schlumberger Introduces Autonomous Directional Drilling. Hart Energy, August
18, 2021. Schlumberger
Introduces Autonomous Directional Drilling | Hart Energy
[5]
Pason’s DAS™ dedicated to faster drilling, saving costs. Pason (website). Pason’s
DAS™ dedicated to faster drilling, saving costs | Pason Systems
[6]
Closed-loop drilling optimization system: implementation and field results from
large-scale deployment. (multiple authors from Pason and ExxonMobil). IADC
Drilling Contractor Magazine, July/August 2020 Issue, pages 35-37. Drilling
Contractor Magazine
[7]
DAS™ best practices. Pason (website). DAS™ best
practices | Pason Systems
[8]
Whitfield, Stephen. Automated steering system aims to improve directional
drilling across multiple onshore US basins. IADC Drilling
Contractor Magazine, July/August 2020 Issue, pages 40-41. Drilling Contractor Magazine
[9]
The future of drilling automation: transforming a vision into reality.
(multiple authors from National Oilwell Varco (NOV) and Chevron). IADC Drilling
Contractor Magazine, July/August 2020 Issue, pages 32-34. Drilling
Contractor Magazine
[10]
Whitfield, Stephen. Drilling fluid digital twins developed to monitor
rheological properties, cuttings transport functionality. IADC Drilling
Contractor Magazine, July/August 2020 Issue, pages 45-46. Drilling
Contractor Magazine
[11]
Maersk Drilling’s first low emission rig shows very promising emission
reduction levels after entering operations in Norway. Maersk Drilling, December
17, 2020. Maersk
Drilling’s first low-emission rig shows very promising emission reduction
levels after entering operations in Norway | Maersk Drilling
[12]
Siemens Energy delivers energy storage solution for Maersk Drilling’s first
hybrid, low emissions jack-up drilling rig. Siemens Energy, February 11, 2021. Siemens
Energy delivers energy storage solution for Maersk Drilling’s first hybrid,
low-emission jack-up drilling rig | Press | Siemens Energy (siemens-energy.com)
[13]
Douglas, Stephanie. August 26, 2021. Nabors launches robotic drilling rig in
the Permian Basin. CBS7.com. Nabors
launches robotic drilling rig in the Permian Basin (cbs7.com)
[14]
Website. Nabors. Equipment. Automated Drilling
Equipment | Nabors
[15]
Drilling waste Management: TCC Rotomill Drill Cuttings Treatment. TWMA
(website). TCC
RotoMill® Drill Cuttings Treatment | TWMA
[16]
Carbon+Intel: TWMA’s wellsite processing solution proven to reduce carbon
emissions of drilling operations by 50%. World Oil, November 15, 2021. Carbon+Intel:
TWMA’s wellsite processing solution proven to reduce carbon emissions of
drilling operations by 50% (worldoil.com)
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