Enhanced oil recovery and CO2 storage a winning combination

• DOI: http://doi.org/10.1111/oet.12733
• Published date: 01 October 2019
• Date: 01 October 2019

LOOKING AHEAD

Enhanced oil recovery and CO

2

storage a winning combination

One of the ways the continued use of fossil fuels can be

squared with carbon emissions goals is by employing carbon

capture, utilization, and storage (CCUS). And as many

basins and fields mature around the world, there is ever more

scope for utilizing the CO

2

in enhanced oil recovery (EOR).

By injecting captured CO

2

into oil fields—rather than gas

from underground sources (or water)—the energy industry

can combine the benefits of carbon storage and higher oil

output, helping improve sustainability and operational

efficiency.

Currently, around 20% of oil projects worldwide use

some form of EOR, and that proportion is rising. One in five

of these already uses CO

2

, although most of this is from

underground sources (see below). If CO

2

from CCUS pro-

jects were used, EOR could provide a significant revenue

stream, in addition to any income that may be generated as a

result of avoiding carbon charges/prices—such as that

imposed by the EU on power and industrial emitters, which

is currently (mid-September) around €27/tCO

2

.

Most sustainable energy scenarios expect CCUS from

both power generation and industrial facilities to grow

quickly to 2040. Carbon dioxide is first captured on site,

then compressed and dehydrated, before being transported

by pipeline and utilized in EOR or another industrial pro-

cess. Any revenues generated could be used to kick-start this

process, helping reduce early project costs and expanding

the amount of CO

2

stored per unit of investment.

The combination of CO

2

capture and EOR is an impor-

tant element in oil companies' pursuit of carbon goals—

which are getting more ambitious. In mid-September, Shell

and Repsol committed to align their business models with

pledges by national governments under the Paris climate

agreement. Then on 23 September, 13 major oil companies,

including BP and ExxonMobil, outlined a plan to promote

investment in CCUS, ahead of the UN climate meeting in

New York. Occidental Petroleum Corp's CEO Vicki Hollub,

said such an approach could make drilling carbon neutral

(see explanation below).

1|UNDERGROUND IRONY

CO

2

is already used in about 100 EOR projects around the

globe, but most of these projects use gas that has been

extracted from underground—either as a constituent that

needs to be removed from the oil and gas being produced or

from separate CO

2

deposits nearby. This only provides an

environmental benefit if the CO

2

would have been released

to the atmosphere if it had not been reinjected, although it

does show it can be done at scale, and that a switch to using

emissions from industry and power generation would be

technically feasible.

According to Christophe McGlade, Senior Analyst at the

International Energy Agency (IEA), the US already injects

an average of between 300 kg CO

2

and 600 kg CO

2

for

EOR per barrel of oil produced –not far off the 500 kg CO

2

the oil produces during extraction and combustion. He said

this “opens up the possibility for the full lifecycle emissions

intensity of oil to be neutral or even carbon-negative,”

depending on the origin of the CO

2

.

The oil and gas industry itself already captures and uti-

lizes a large proportion of its own emissions. Nearly 70% of

the 30mnt CO

2

or so captured today from industrial activi-

ties in large-scale CCUS facilities is from oil and gas

operations—which are often well placed to make use of it,

either by selling the CO

2

to industrial facilities or by using it

for EOR. The CO

2

can also blend with the oil after injection,

improving its mobility and so allowing it to flow more

easily.

The demand for EOR is rising all the time as fields and

provinces mature. For example, PD Oman expects to more

than double the amount of oil produced from EOR to 23%

of total output by 2025, up from 11% today. CO

2

injection is

also seen as a promising method to rejuvenate shale oil pro-

duction after initial output begins to decline, which should

begin to happen soon—increasing the importance of the

technique. The Century and Petra Nova plants in Texas are

examples of large EOR schemes that already use CO

2

from

industry/power generation.

2|ADNOC SETS EXAMPLE

Abu Dhabi's state oil and gas firm, ADNOC, uses CO

2

for

EOR extensively. Further utilization is planned, using more

cost-effective second and third-generation carbon capture

technologies. In total, ADNOC plans to capture about 5mn

tons of CO

2

/year (250mncfd) before 2030 and estimates the

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