Tinsley Field in Yazoo County was Mississippi’s first commercial oil field, discovered on August 29, 1939, when Union Producing drilled the No. 1 G. C. Woodruff to 4,560 feet and tested oil from the sand that now bears the landowner’s name. Cumulative production exceeds 224 million barrels of oil along with substantial gas. Beginning in 2007 the field was converted to tertiary carbon dioxide flooding, eventually extended across all three fault blocks — a second life that has made a 1939 discovery one of the more technically active properties in the Mississippi Salt Basin.
Mississippi had been drilled without success for years before August 29, 1939, when a drill stem test in the Union Producing No. 1 G. C. Woodruff finally produced oil at 4,560 feet in Yazoo County. The interval was named the Woodruff sand after the landowner, and the discovery opened an entirely new producing state. Leasing swept across the Yazoo County countryside, and the mineral reservations executed in the months that followed are the foundation of much of the fractional ownership recorded in the county today.
Development through the 1940s established Tinsley as a major field, with production from Upper Cretaceous sandstone in a faulted structure divided into distinct blocks. Primary production drained pressure, waterflooding followed, and by the late twentieth century the field had produced the bulk of what conventional methods could recover. Ownership fragmented through eight decades of estates and conveyances, and operatorship passed through a succession of companies as the field moved from major-company asset to specialist enhanced-recovery target.
The modern chapter began in 2007, when Denbury Resources initiated a tertiary carbon dioxide flood in the Woodruff sand using CO2 from the natural accumulation at Jackson Dome. The project was extended across all three fault blocks and tertiary production exceeded 12,000 barrels a day at its 2014 peak before easing back. ExxonMobil acquired Denbury in 2023, and current operatorship and development plans should be confirmed against present records rather than assumed from historical accounts.
Tinsley produces from Upper Cretaceous sandstone — the Woodruff sand, a concretion-rich unit within the Selma and Eutaw section — trapped on a faulted structure in the Mississippi Salt Basin. The structure is divided into three principal fault blocks, each with its own pressure and flood history, which is why development and enhanced recovery have proceeded block by block rather than field-wide. Depths are around 4,500 feet. The concretionary character of the sand creates internal heterogeneity that complicates sweep, one reason vertical conformance has been a focus of the CO2 project.
Tinsley is a carbon dioxide flood. Since 2007 CO2 sourced from the Jackson Dome accumulation in central Mississippi has been injected into the Woodruff sand, dissolving into and swelling the remaining oil so it can be moved to producers — a method that recovers oil waterflooding leaves behind. The project was extended across all three fault blocks, and dedicated injectors were added to improve vertical sweep in the heterogeneous sand. Tertiary rates peaked above 12,000 barrels a day in 2014. CO2 floods require sustained capital and pipeline supply, so their pace can change with ownership and price.
A CO2 flood changes what a Mississippi royalty interest is worth, and generic valuation formulas do not account for it. Tertiary response arrives on a different schedule than primary or waterflood production, varies by fault block, and depends on continued injection and CO2 supply. Pricing an interest here requires knowing which block your tract sits in and what the flood is actually doing. We underwrite that way, and we buy direct: we buy minerals and royalties in Yazoo County and provide free written offers.
County-level well data, production charts, and selling guides for the counties this field spans:
Royalty is still paid on oil produced and sold, but the production profile is different. Tertiary response often means volumes rise for a period after injection reaches your part of the reservoir, then decline again, and the timing varies by fault block. Some leases respond strongly and others little. That is why we look at actual well-level history rather than assuming a flood lifts every tract equally.
The CO2 flood was developed by Denbury, and ExxonMobil acquired Denbury in 2023. Operatorship and development plans can change, so we verify current operator and status from Mississippi records rather than relying on published histories. Your division order and check stub will name the paying party, which is the most reliable starting point for your own interest.
Typically the original mineral reservation or deed, the probate or heirship record for each generation since, and a recent division order or check detail. Mississippi interests of this age often have gaps where an estate was never probated. We identify those early, explain what curing them requires, and provide the offer in writing so you can decide with full information.