Utilizing CO2 for Enhanced Oil Recovery

Initiative for the Cool Earth ForumOctober 10, 2019

PROFESSOR SALLY M. BENSON

DEPARTMENT OF E NERGY RESOURCES E NGINEERING

STANFORD, CA

Conventional CO2-EOR: With Water-Alternating-Gas

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From Lindley, 1986.

• CO2 forms a miscible mixture with oil to enhance recovery• Improves recovery of the initial oil in place from about 30 to 60%

CO2 Enhanced Oil Recovery & Storage

Global Deployment of CO2-EOR

4Source: IEA

• 2018: 97 projects world wide

• 90% in U.S.• Starting to see growth in

China, Brazil, Middle East

Current Status of CO2 EOR

� Largest current use for CO2

� 65 Mt CO2 per year for EOR

⁻ ~50% from anthropogenic sources

� 3% of U.S. oil production today from CO2-EOR (300,000 bbl/day)

� Engineering designed to minimize the amount of CO2 injected per barrel recovered

⁻ 1 bbl oil produced per 0.3 tonne to 0.6 tonne CO2

� Large upfront investments in wells and other infrastructure limit investment in CO2 EOR

� High costs of captured CO2 are a deterrent to deployment

� High purity CO2 sources at a cost of ~$30-$40 per tonne are attractive

Advanced CO2-EOR & Sequestration for Conventional Reservoirs

6From Rao, 2006

Traditional CO2-EOR minimizes CO2

inputs

Advanced CO2-EOR optimizes CO2

inputs for recovery and storage

Reducing the carbon intensity of oil production and increasing production from existing resources

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• Doubling or tripling CO2/bblyields higher ultimate recovery and provides Gt scale CO2reductions

• Reservoir engineering methods for co-optimization need to be developed

• Incentives will be required to stimulate technology development

Benson and Deutch, 2018, Advancing Enhanced Oil Recovery as a Sequestration Asset, Joule.

Burning 1 bbl oil = 0.43 tonnes CO2

0.4 tonne/bbl

0.8 tonne/bbl

Co-Optimization of CO2-EOR and Storage: Gravity Stable Immiscible Flood

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From Daniel Hatchell, Stanford MS Thesis, 2017

Turning Oilfields into CO2 Storage Assets

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� Oilfields provide significant storage assets (estimated at 1000 Gt of CO2)� CO2-EOR supports building infrastructure for long term CO2 mitigation with CCUS (pipelines,

markets)⁻ Reinvigorates investment in brown-field oil reservoirs for CO2-EOR and as storage resources – avoiding

large investment in potentially stranded assets⁻ Puts in place infrastructure (e.g. pipelines, wells, and monitoring) for taking advantage of stacked

reservoirs for large scale storage

� Creating a new paradigm: Carbon Neutral Oil� Co-optimization of CO2-EOR and storage needs innovation, experimentation, and learning� Governments should incentivize experimentation with Advanced CO2-EOR� Examples in include U.S. 45Q tax credit and reverse Dutch Auction (Benson and Duetch,

2018)