Brief
Pore Space Rights – U.S. Overview

Global CCS Institute
Ruth Ivory-Moore, Policy and Advocacy Manager, the Americas

May 2022

Overview
Sequestering carbon dioxide (CO2) in the United States (U.S.) in subsurface geologicalformations presents a unique property law issue, pore space ownership.
Understanding the difference between surface and mineral estates is essential when
making land purchases, contractual arrangements for carbon storage, and analyzing
pore space ownership. The surface estate includes everything above the ground, suchas trees, the land, and buildings. The mineral estate refers to underground resources
such as oil, gas, and other minerals.
This document provides information on the property rights related to pore spaceownership within the United States. The issue of pore space ownership is largely
settled for carbon capture and storage (CCS) in many other jurisdictions around theworld. However, as the U.S. law is not sufficiently settled, each party should consult
local counsel to draft leases and other carbon dioxide storage-related documents.

Summary
CO2 will be sequestered in the pore space of the geologic formations. Pore spaceownership is not always clear and often an unsettled area of property rights law,
creating uncertainty in many states. Ownership of the pore space should not be
presumed to be vested in the surface owner, especially when there has been aseverance of the surface estate and mineral estate. However, most states in the UnitedStates seem to follow what is known as the American rule. Under American rule, themineral estate holder owns the minerals but not the geologic formation. The surface
owner owns the geologic pore space and has storage rights. "A caveat to this rulestates that surface estates, under the American rule, must allow the oil and gas
company holding the mineral estate to complete their extraction of minerals andcompletely deplete the subsurface area before leasing the pore space to another." 1
The English rule takes the position that the mineral estate owner owns the natural
resources and the pore space.
There is an added complication in split estates, where the same person does not own
the surface and mineral estates. "In much of the United States, it is common for mineralrights to have been severed from surface ownership by prior reservation, leaving
surface and mineral ownership in separate hands. In the public land states of theWestern United States, the "split estate" issue primarily arises from federal landdisposition laws, most notably the Stock-Raising Homestead Act (SHRA) of 1916, which
expressly reserved minerals to the federal government for over 50 million acres
around the west. Courts in these cases have generally concluded that the use ofgeologic pore space is not associated with the mineral estate since the pore space
represents the absence of minerals and that the surface owner, therefore, owns
geologic storage rights. In other situations, such as the construction of solution-minedcaverns in subsurface salt deposits, ownership of void space has been an attribute of1the mineral estate. However, there is enough nuance in the law of individual statesthat broad conclusions are difficult to draw without substantial local law research.2,8Even in cases where the state follows the American rule, there may be underlying
documents that could mandate the court issue an opinion that is not consistent withthe rule followed. For example, in "Ellis v. Arkansas Louisiana Gas, an Oklahoma case,
the Tenth Circuit held that, in general, the pore space belonged to the surface ownerfor gas storage purposes; however, in this particular case, the mineral owner prevailed
because the court found a prescriptive easement. A prescriptive easement allows
someone other than the original property owner to gain the right to use a property.
This easement typically arises after a long, continuous, adverse, open use of a rightof-way over someone else's property for a certain amount of time. The amount of time
may vary by state.
Those looking to sequester CO2 should perform due diligence research regarding theproperty rights laws in the area(s). Unfortunately, the law is unsettled, and ancillaryfactors could yield opinions contrary to the general understanding of the governing
rule (American or English). Table I depicts the uncertainty that remains in this area ofproperty law in the United States.
Table I: Pore Space Ownership Summary
StatePore SpaceOwnership

Reference(s) Comments

Arkansas

Likely to follow
American Rule3, 7

California

Unsettled

6, 10

The prevailing rule appears to be that thesurface owner owns the pore space.
For lands subject to the SRHA, the federal
government likely owns the pore space.
Colorado courts have not directly addressed
who owns the pore space

Colorado

Unsettled

8, 3, 10

Idaho

Undecided

8

KansasUndecided

12

KentuckyAppears to bemineral owner

4, 10

Court in Central Kentucky Natural Gas v.
Smallwood applied the English rule that is, “themineral owner possesses the exclusive right ofproduction as well as the exclusive right to thestorage space left after production has ceased.”
Surface owners argue English rule is notapplicable.22LouisianaSurface owner

4, 10
But the court In Department ofTransportation v. Goike, the Michigan Court ofCaveat:

Michigan

Surface owner

4, 10Montana

Surface owner

2, 6, 10

Appeals made it clear that when native oil orgas remains in the pore space, the mineralowner may preclude the surface owner fromusing the storage space…

New Mexico’s policy towards ownership of porespace is somewhat ambiguous because thestate and public entities have the right to use
aquifer storage to recharge the aquifer. Oldercase law appears to indicate the surface ownerhas pore space ownership.10

New Mexico

Appears to be
surface owner

4, 10

New York

Appears to be
surface owner10

North Dakota

Surface owner

2, 6

Ohio

Undecided

10

Oklahoma

Appears to be
Surface owner

4, 10

Pennsylvania

Undecided

10

There are no Pennsylvania cases directlyaddressing the ownership of pore space inPennsylvania.

Ohio courts have not spoken directly as to whoowns the pore space.

Texas

See comments

1, 4, 5, 10

In Texas, there is no clear general rule on which
estate, surface or mineral, possesses ownershipof the pore space for storage purposes unlessthe severance contract expressly specifies.
There are multiple cases in Texas that offer
conflicting results regarding whether the state
follows the English or American Rule.

Utah

Undecided

13

Pore space rights are currently in an initialabsolute stage of development.13

West Virginia

Appears to be
surface owner4, 10Case law appears to support surface owner.10

Wyoming

Surface owner

5, 6, 93

References

1.

“Understanding ‘Pore Space” Law in Oil and Gas Litigation”,
https://burfordperry.com/understanding-pore-space-law-in-oil-and-gas-litigation/.

2. “Who Owns Pore Space for Geologic Carbon Sequestration? Renewed Focus on Carbon
Capture and Storage Likely to Bring Ownership Uncertainties on Western Split-Estate Lands
Back into the Picture”, https://www.jdsupra.com/legalnews/who-owns-pore-space-forgeologic-carbon-2984045/.
3.

“A 2015 Analysis and Update on U.S. Pore Space Law —The Necessity of Proceeding
Cautiously With Respect to the “Stick” Known as Pore Space”,
https://digitalcommons.law.ou.edu/cgi/viewcontent.cgi?article=1013&context=onej.

4.

“Part 2: Analysis of Property Rights Issues Related to Underground Space Used for Geologic
Storage of Carbon Dioxide”, https://cdrlaw.org/wpcontent/uploads/2020/10/PropertyRights.pdf.

5. “Horizontal Drilling and Trespass: A Challenge to the Norms of Property and Tort Law”,
https://www.colorado.edu/law/sites/default/files/Kramer%2025-2.pdf.
6. “Environment, Land Use & Natural Resources Advisory: Carbon Capture & Sequestration
Faces Significant Permitting and Regulatory Obstacles in California”,
https://www.alston.com/en/insights/publications/2021/08/pending-california-legislationhighlights-need.
7.

“PORE SPACE AS A PROPERTY RIGHT: WHAT IS IT, WHO OWNS IT AND WHAT IS IT
WORTH?”
https://www.wylr.net/2017/12/16/pore-space-as-a-property-right-what-is-it-who-owns-it-andwhat-is-it-worth/.

8.

“Does the Federal Government Own the Pore Space Under Private Lands in the West?
Implications of the Stock-raising Homestead Act OF 1916 For Geologic Storage of Carbon
Dioxide”, https://law.lclark.edu/live/files/11617-422doranpdf.

9. “State and Regional Control of Geological Carbon Sequestration”,
https://www.osti.gov/servlets/purl/1158542.
10. “Who Owns the Right to Store Gas: A Survey of Pore Space Ownership in U.S. Jurisdictions”,
http://www.duqlawblogs.org/joule/wp-content/uploads/2016/07/Who-Owns-the-Right-to-StoreGas-A-Survey-of-Pore-Space-Ownership-in-U.S.-Jurisdictions-.pdf.
11. “Geographic Availability,” https://climate.law.columbia.edu/sites/default/files/content/CO2EGU-NSPS-TSD-Geographic-Availability.pdf.
12. “Testimony before the Joint Committee on Energy and Environmental Policy Ownership ofunderground pore space”,
http://kslegislature.org/li_2012/b2011_12/committees/misc/ctte_jt_engy_envrn_plcy_1_20111017_39_other.pdf.
13. “Pore Space Property”,
https://dc.law.utah.edu/cgi/viewcontent.cgi?article=1277&context=ulr#:~:text=Anadarko%20E%
26P%20Onshore%20LLC%20upheld,the%20subsurface%20pore%20space%20and.

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