Mississippi CO2 Floods — A Mineral Owner's Overview

Jackson Dome — The CO2 Source

Jackson Dome — located in Rankin County, Mississippi — is the only natural CO2 reservoir east of the Mississippi River. Discovered in the 1970s and developed for industrial CO2 supply through the 1980s-1990s, Jackson Dome is the foundation of the Mississippi CO2 EOR industry. The reservoir produces high-purity CO2 that is delivered through the Denbury "Green Pipeline" / NEJD CO2 pipeline system to multiple Mississippi CO2 EOR target fields.

Jackson Dome CO2 supply is the binding economic constraint on Mississippi EOR. The reservoir has finite remaining supply, and operator-side allocation decisions (which fields get CO2 first) materially affect long-term reserve life projections for any individual flood.

Major Mississippi CO2 Flood Fields

Fields fed by Jackson Dome CO2 supply (top 20 mature/EOR list):

Heidelberg East (Jasper County, Denbury) — 49,508 bbl Jan 2026; the largest single-position MS CO2 flood

Eucutta East (Wayne County, Denbury) — 36,148 bbl Jan 2026

Tinsley (Yazoo County, Highmark Energy Operating) — 32,852 bbl Jan 2026; classic mature CO2 / waterflood field

Heidelberg West (Jasper County, Denbury) — 26,630 bbl Jan 2026

Brookhaven (Lincoln County, Denbury) — 19,107 bbl Jan 2026

Soso (Jasper County, Denbury) — 3,931 bbl Jan 2026

Cranfield (Adams County, Durango Operating) — 398 bbl Jan 2026; the first commercial Mississippi CO2 flood (Denbury 2008) and SECARB sequestration test site

The ExxonMobil Acquisition of Denbury (November 2023)

In November 2023, ExxonMobil acquired Denbury Resources for approximately $4.9 billion. The acquisition was driven primarily by ExxonMobil's interest in Denbury's CO2 transportation and sequestration infrastructure — the Jackson Dome CO2 supply, the NEJD / Green Pipeline system, and the established Denbury CO2 EOR field portfolio.

For Mississippi mineral owners with interests on Denbury-operated CO2 floods, the post-acquisition implications include:

Operator-of-record migration: Mississippi state filings still show "Denbury Onshore" as operator on most fields, but ExxonMobil rebranding to "ExxonMobil Low Carbon Solutions" is in progress (one well already visible in the data)

CO2 allocation strategy: ExxonMobil may shift CO2 allocation between EOR (oil production) and sequestration (45Q tax credits). This affects long-term reserve life on individual EOR floods.

Capital deployment: ExxonMobil's broader portfolio focus (Permian + offshore) may not prioritize Mississippi EOR maintenance investment at the same pace as Denbury historically did

Cranfield: The CO2 Sequestration Pivot

The Cranfield field in Adams County is historically significant as the first commercial Mississippi CO2 flood (Denbury 2008) AND the SECARB CO2 sequestration test site. Currently operated by Durango Operating, the field is likely transitioning toward sequestration-only operations rather than continued EOR. For mineral owners on Cranfield, the field's economic role is shifting from oil production (small bbl amounts) to CO2 sequestration (45Q tax credits to the operator).

For broader 45Q tax credit context, see our 45Q Tax Credits for Mineral Owners guide.

Mineral Owner Implications

If you own a mineral or royalty interest on any Jackson Dome-supplied CO2 flood, your interest's long-term value depends in part on operator-side CO2 supply decisions. Post-ExxonMobil acquisition, those decisions are now part of ExxonMobil's broader Low Carbon Solutions strategy. A current mineral valuation should explicitly account for CO2 supply scenario risk and the possibility of EOR-to-sequestration transition.

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Free written offers grounded in current Jackson Dome CO2 supply scenarios.