DECARBONIZING DRILLING
Companies zero in on cementing
process to have outsized impact
on well construction emissions
Solutions being deployed include well planning
and emissions monitoring software, as well as
technologies with reduced Portland cement
BY STEPHEN WHITFIELD, ASSOCIATE EDITOR
As the world continues to move toward a
low-carbon future, the oil and gas indus-
try’s ability, to not only reduce its emis-
sions but also to quantify its emissions
reduction performance, has become a pri-
ority. One component of the well construc-
tion process with significant potential for
emissions efficiency is cementing. Studies
have shown the production of cement to
be an emissions-intensive process involv-
ing heating kilns to very high tempera-
tures, as well as calcination, a chemical
reaction that occurs when raw materials
like limestone are exposed to those high
temperatures. Other steps like quarrying
and transport also add to the emissions
footprint. That’s why operators like BP are work-
ing on reducing their use of cement in
well construction, while cementing solu-
tions providers target reducing the car-
bon footprint of cement production, said
Emmanuel Therond, BP Technical Advisor.
One part of BP’s work in this area is
its Well Design Optimizer software pro-
gram, launched last year. It’s a tool that
its engineers can use to estimate green-
house gas (GHG) emissions as they are
planning wells. Cementing is one of four
components that the software measures,
along with fuel usage, planned testing and
planned casing, Mr Therond explained in
at the 2023 IADC World Drilling Conference.
The software uses pre-established
emissions factors to obtain estimates of
CO 2 generation from various activities.
Emissions factors are representative val-
ues that attempt to relate the quantity of
36 a pollutant released into the atmosphere
with an activity associated with the
release of that pollutant. When multiplied
by activity indicators input by the drilling
engineer, the software can provide an esti-
mate of the CO 2 emissions that the given
activity will generate.
Mr Therond noted that the software
is not a tool for reporting or calculating
emissions; the estimates generated by the
software are only shared within BP and
with its third-party contractors. The goal,
rather, is to help personnel decide if any
actions can be taken through better well
planning to help reduce emissions.
“This is a tool for estimating emissions
so that drilling engineers can understand
what options they have to reduce emis-
sions without compromising the well’s
construction,” he said. “It might sound very
simplistic, but I think this is the first step,
so we can start understanding and acting
upon these numbers. Right now, we don’t
have the tools that allow us to have quality
conversations with the drilling engineers.”
One of the first projects where BP
deployed the Well Design Optimizer was
an offshore well drilled last year in the
Mediterranean Sea. The process began by
entering data related to:
rig type (drillship);
number of days planned to drill the well
(183);
estimated diesel consumption (31
tonnes/day);
the type of well testing (flaring);
the specific gravity of the gas flared dur-
ing testing (0.70);
duration of testing (1 day);
Reducing the use of carbon-intensive
Portland cement in well cementing op-
erations can help the industry to reduce
its overall emissions profile, said Patrick
Lynch, Regional Business Development
Lead – Low Carbon Ventures at Halli-
burton, at the IADC World Drilling Con-
ference in London on 21 June.
the production rate during well testing
(50,000 standard cu ft/day); and
the slurry densities for each hole section
in the well.
From these inputs, the software gener-
ated an emissions estimate for the well,
multiplying select variables by given
emissions factors for each variable. It esti-
mated that the well would generate nearly
24,000 tonnes of CO 2 over its lifetime, and
only 2% of that would come from cement
usage. Since that is within the 1-5% aver-
age range BP typically sees, it confirmed
no action was required to revise the well
plan and cement usage. If the estimates
had been abnormally high, however, the
operator could have taken early steps to
alter the design.
Reducing Portland cement
in completions
Halliburton is also working to help
operators reduce emissions from cement-
ing through its Verified Integrated Design
Application (VIDA) and Envana Catalyst
emissions monitoring software. VIDA is a
design modeling software that identifies
the risk mitigation factors within a well’s
design; it can also be paired with Envana
Catalyst to provide a comprehensive esti-
mate of the amount of CO 2 generated by
SEPTEMBER/OCTOBER 2023 • DRILLING CONTRACTOR
DECARBONIZING DRILLING
specific pieces of equipment used on a
well during the well’s lifecycle.
To get these estimates, the drilling
engineer first inputs basic data for the
planned well, including the number of
days planned to use a given piece of equip-
ment. Those inputs are then automati-
cally transferred to the Envana Catalyst
program, which runs them against other
inputs and emissions data stored in a his-
torical database from equipment used on
similar wells drilled by Halliburton clients.
Using the inputs provided by the drill-
ing engineer, as well as the historical data,
the Envana Catalyst program calculates
emissions estimates for the rig’s equip-
ment and displays the results within VIDA.
Once the well is drilled, the emissions data
from the equipment is input into Envana
to provide additional data points for future
well designs.
“We have the information from years
and years of our operations, and thousands
of calculations in different geography
iterations,” said Patrick Lynch, Regional
Business Development Lead – Low Carbon
Ventures at Halliburton. “We’ve learned a
lot because, if you’re simulating cement-
ing operations around the world, there are
a lot of different options you can take with
the blend.”
The software systems, when combined,
can provide a granular breakdown of
which parts of the drilling and completions
process are generating the most emissions.
At the World Drilling conference, Mr Lynch
discussed a pair of cementing operations,
one from an offshore well and one from
onshore. For the offshore well, users input
the expected pumping hours and idle hours
for the rig’s cement pumping unit, along
with the location of the well, the estimated
mileage transporting the cement from the
manufacturing site to the rig, the type of
cement used (Portland cement), the batch
mixer and the liquid additive system.
From those inputs, the Envana system
estimated that 98% of the emissions gener-
ated from cementing would come from the
production of the cement blend, with the
remaining 2% split among the batch mixer,
cement pumping unit and the liquid addi-
tive system.
The onshore well saw similar results: It
was estimated that 81% of the cement job’s
emissions would come from the cement
A 2020 report by McKinsey & Company, citing 2017 data from the Global Cement
and Concrete Association, showed that the majority of CO 2 emissions generated
during cement manufacturing came from the preheating and precalcinating pro-
cesses, where raw materials are exposed to high temperatures.
blend, 14% from the consumption equip-
ment (the cement pump truck, storage bin
and the bulk truck), and the remaining 5%
from transportation of the cement to the
wellsite. These examples were indicative of a
larger trend Halliburton noted in its emis-
sions data, Mr Lynch said – that the pro-
duction of cement accounted for more
than 90% of the total emissions from its oil
well cementing operations. This highlight-
ed the importance in reducing the amount
of cement used. In 2021, the company
launched its NeoCem E+ and EnviraCem
systems, which contain a reduced amount
of Portland cement mixed with locally
sourced byproducts. Compared with the
company’s conventional cementing sys-
tem, the NeoCem E+ system contains 50%
less Portland cement while EnviraCem
cement contains 70% less.
Using locally sourced byproducts
is the key differentiator for these solu-
tions, Mr Lynch said. When companies
create cementing solutions with reduced
Portland cement, they often sub it out with
mined materials that can only be found in
limited locations around the world. This
leads to additional CO 2 emissions from the
extraction and the logistics of transporting
them to a facility for processing.
Because NeoCem E+ and EnviraCem
“are heavily comprised of locally produced
products and some minor manufactured
components, they can provide reduced
CO 2 emissions in our cementing opera-
tions,” Mr Lynch explained. “The point
is, rather than having a single source for
the raw materials in our cement and then
transporting that around the world, we’re
trying to take away the transport-related
aspect of the emissions wherever pos-
sible.” In addition to emissions-related ben-
efits, the reduced-Portland cement sys-
tems can also better withstand the down-
hole demands from continual pressure
and temperature changes throughout the
life of the well compared with conven-
tional cement systems. He credited this to
Halliburton’s approach to specifically tai-
loring its reduced-Portland cement blends
to the needs of specific cementing jobs.
“We can leverage our database of lab test-
ing along with our physiochemical under-
standing of the materials to create tailored
engineered systems designed to produce
specific properties downhole. Every cement
is specifically engineered to do an efficient
job, and we’re seeing benefits in properties
like thickening, fluid stability and fluid loss
control,” he said. DC
DRILLING CONTRACTOR • SEPTEMBER/OCTOBER 2023
37