The Big Wells Field straddles the Dimmit and Zavala county line in the Winter Garden region of South Texas, producing from the Upper Cretaceous San Miguel sand in the Maverick Basin. It came in during the late 1960s, long after most of the state’s famous fields, and gave two farming counties a genuine oil economy for the first time. Dimmit County production, which had run in the hundreds of thousands of barrels a year through the 1950s, exceeded seven million barrels by 1972. Today the field is a mature waterflood worked at modest rates.
Source: Texas Railroad Commission production filings, aggregated across RRC field designations 08072500, 08072750. Reported volumes lag the calendar by several months.
Oil in Dimmit County had a long and discouraging prelude. Traces turned up in 1903 in wells drilled for water, systematic exploration began near Las Vegas around 1915, and the Handbook of Texas records that the first producing well was not found until 1943. Even then the results were small: county production was 973 barrels in 1947 and 56,947 barrels in 1954. The rocks were known to hold oil, but the shallow San Miguel sands were tight, the oil was heavy, and nobody had yet worked out how to make them pay at scale.
That changed at the end of the 1960s with the development of the Big Wells Field. Dimmit County production, which had passed 513,000 barrels in 1958, rose above 7,445,000 barrels in 1972. By 1980 oil and gas had become the county’s largest source of income at roughly sixty million dollars a year, ahead of the irrigated vegetable crops the Winter Garden was named for. The town of Big Wells, which had been a farming community, came to depend on oilfield work for its livelihood.
The field matured quickly, as shallow sand reservoirs tend to. Waterflooding was applied to sustain pressure and sweep oil the primary wells left behind, and later operators used the horizontal drilling techniques that the Handbook of Texas notes had begun bringing old area fields back to life by 1989. The Eagle Ford boom of the 2010s brought new drilling to both counties, but that activity targets a deeper shale rather than the San Miguel. Big Wells itself remains a mature secondary-recovery property.
Big Wells produces from the San Miguel sand, an Upper Cretaceous shoreline and deltaic sandstone that lies at shallow depth across the Maverick Basin of Southwest Texas. The sands are fine grained and only moderately permeable, and the oil they hold is heavy and viscous compared with the light crude of West Texas. Trapping is stratigraphic, controlled by where the individual sand bodies thin and pinch out, rather than by a single large structure. That combination explains both the field’s late discovery and its dependence on injection to move oil toward producing wells.
Waterflooding is the core of Big Wells operations. Injected water maintains reservoir pressure and pushes oil through a sand that gives it up slowly, which is the only way a shallow, viscous-oil reservoir of this kind sustains commercial rates for decades. Operators have supplemented the flood with infill drilling, pattern changes and horizontal wells that expose more sand face per wellbore. Expectations should stay realistic: the field is well past its peak, and the work here is about slowing decline and lowering lifting costs rather than about restoring 1970s production levels.
Big Wells royalties are secondary-recovery income, which behaves differently from a shale royalty. Rates are low but steady, decline is gradual, and the value of an interest turns on whether the operator keeps injecting rather than on a drilling forecast. Many Dimmit and Zavala owners also hold deeper rights that were leased separately during the Eagle Ford boom, and those two revenue streams are often mixed up on a single check. Sorting out which formations and which leases you are paid on comes first. We buy minerals and royalties in Dimmit and Zavala counties and provide free written offers.
County-level well data, production charts, and selling guides for the counties this field spans:
Usually not in practice. The San Miguel sand at Big Wells is shallow, while the Eagle Ford shale is thousands of feet deeper, and the two are frequently held under separate leases with different operators and different royalty decimals. Your check stubs will show separate property or lease numbers. If you send us the stubs we can separate the shallow waterflood income from the shale income.
Because without it the wells would have quit long ago. Injection replaces reservoir energy and pushes oil toward producing wells, which is what keeps a shallow heavy-oil sand paying. The practical consequence is that the health of your royalty depends on the operator continuing to spend money on injection, water handling and workovers, so operator quality matters more here than in a shale field.
That depends on your situation rather than on any forecast. Mature South Texas waterflood royalties produce small, steady checks with a long tail, and some owners prefer a lump sum to decades of modest payments. Others value the optionality of deeper zones. We provide a free written offer with no obligation so you can compare holding against selling on your actual numbers.