The Greta Field sits on the Refugio County coastal plain and lends its name to the Greta sand, the Oligocene Frio barrier-bar reservoir that produced one large field after another along this stretch of the Texas Gulf Coast. The Handbook of Texas dates the opening of the Greta field to 1928 and credits it with demonstrating the tremendous potential of the area for oil production. It adjoins the much larger Tom O’Connor field to the south. Today Greta is a mature, waterflooded property with a long history of unit operation behind it.
Source: Texas Railroad Commission production filings, aggregated across RRC field designations 36867012, 36867024, 36867048, 36867073, 36867132, 36867156, 36867204, 36867216, 36867240, 36867312, 36867348, 36867372, 36867396, 36867492, 36867504, 36867600, 36867624, 36867764, 36867780, 36867900. Reported volumes lag the calendar by several months.
Refugio County had a long prehistory of oil talk before anything commercial happened. Local accounts place a discovery near St. Mary’s around 1870 during water-well drilling, and serious exploration began in the 1910s. Gas production started around 1926 with the completion of a Houston Gulf Company pipeline. The breakthrough came with the Greta field, which the Handbook of Texas says opened in 1928 and showed how much oil lay in the Frio sands beneath the coastal ranchlands. Drilling spread rapidly across the county in the years that followed.
The results were extraordinary by any standard. Refugio County produced almost 9,756,000 barrels of crude in 1936, almost 25,000,000 barrels in 1944 and almost 30,240,000 barrels in 1948. Greta was one of the first fields in that surge, and the barrier-bar sand it produced from became the type example for the whole trend, so that geologists across the coast came to call the interval the Greta sand. The 1934 discovery of the Tom O’Connor field on the adjoining ranchlands confirmed how large the accumulation really was.
Development at Greta followed the coastal pattern: multiple stacked Frio sands, each with its own pressure system, worked through unit operations that allowed injection to be managed across lease lines. Water injection and, in places, gas reinjection sustained pressure long after primary depletion would have ended production. County output has declined steadily since the mid-century peak, and Greta today is a small, long-lived property rather than a growth asset. Its wells are old, the reservoirs are well swept, and the value lies in longevity.
Greta produces from Oligocene Frio sandstones laid down as barrier bars and strandplain sands along an ancient shoreline that ran roughly parallel to the modern coast. The sands are clean, porous and permeable, and they are stacked in a series of separate reservoirs divided by shales, which is why a single tract can participate in several distinct pressure systems. Trapping in this part of the coast is structural, associated with folding on the downthrown side of the Vicksburg fault zone rather than with a salt dome. That setting produces broad, gently folded fields with extensive sand bodies.
Recovery at Greta has depended on maintaining reservoir pressure through injection rather than on any exotic method. Water injection, and in parts of the trend the reinjection of produced gas, keeps oil moving toward producing wells in sands that would otherwise deplete their natural drive within a couple of decades. Later work has focused on recompleting existing wellbores into sands that were bypassed during the original development, and on reactivating idle wells when prices justify it. There is no carbon dioxide flood on this part of the coast, so remaining recovery depends on injection discipline and operating cost.
Greta interests are typically small, old and split across several units, which is the single most common source of confusion for owners here. A tract can participate in more than one reservoir unit, each with its own decimal and its own production, so an owner who tracks only the largest check may be undercounting what they hold. Refugio County title also runs back to nineteenth-century ranch families and is often deeply fractionalized. Those streams deserve a careful, unit-by-unit valuation. We buy minerals and royalties in Refugio County and provide free written offers.
County-level well data, production charts, and selling guides for the counties this field spans:
It is the name geologists give to a productive Oligocene Frio barrier-bar sandstone along the middle Texas coast, taken from the Greta field in Refugio County where it was first well described. The same interval produces in several nearby fields, including Tom O’Connor. A reference to Greta sand production does not necessarily mean your interest is in the Greta field itself.
No. They are adjoining fields in Refugio County that produce from the same Frio sand trend, but they were discovered separately, are operated separately and have separate units and royalty decimals. Tom O’Connor is far larger. If your check stubs reference both, you hold interests in two distinct properties.
Because coastal fields were unitized reservoir by reservoir. Each unit covers a different sand with its own participation formula, so your tract can generate several decimals at once. When we value an interest here we ask for all the stubs rather than the largest one, so that every unit is counted.