Coalinga, on the arid west side of Fresno County, is one of California’s original oil giants. First tapped in 1887 at the Oil City pool north of town, it boomed at the turn of the century and by the early 1900s was among the largest producing fields in the world. Cumulative production stands near a billion barrels, and the field still runs today as a steam-flood operation across the Temblor and Etchegoin zones. Few royalty streams anywhere trace their lineage further back than a Coalinga check.
Oil was struck in the Coalinga district in 1887, when shallow wells near the coal-mining camp that gave the town its name found heavy crude in the Oil City pool. The great expansion came between 1898 and 1910: gushers on Anticline Ridge, notably the famous Blue Goose well, drew Southern Pacific interests, Standard Oil, and a rush of independents, and Coalinga briefly ranked among the most productive oil districts on earth.
The prolific Miocene Temblor pool on the east side powered the early decades, then declined as pressure depleted. Attention shifted to the west side’s shallower, heavier Etchegoin and Temblor accumulations, which resisted primary recovery. Beginning in the 1960s, operators applied cyclic steam and steam drives — among the earlier large thermal projects in the state — reviving a field then already seventy years old.
Through the modern era the field was split mainly between Shell and Chevron lineages; Shell’s side passed into Aera Energy in 1997, which became part of California Resources Corporation in the 2024 merger, while Chevron has continued operating its Coalinga properties. The field has also hosted notable pilots over the years, including solar-generated steam, reflecting the constant search for cheaper heat.
Coalinga production comes from two main systems flanking Anticline Ridge on the west margin of the San Joaquin Basin. The Miocene Temblor Formation — sandstones at roughly 700 to 4,600 feet — held the enormous early-day east-side pool. The Pliocene Etchegoin sands, shallower and charged with heavier oil, dominate the west side that thermal recovery later unlocked. Traps combine the anticlinal fold with updip tar seals and stratigraphic pinch-outs. Oil gravity varies widely across the field, which is why some areas flowed naturally in 1905 while others needed steam in 1965.
Modern Coalinga is a thermal field. Operators inject steam both cyclically — heating a single well, then producing it back — and as continuous drives pushing oil between wells. Because the west-side crude is heavy and shallow, royalty volumes depend directly on sustained steam injection, which in turn depends on fuel costs and CalGEM injection permitting. Coalinga has also been a proving ground for steam innovation, including a large solar-thermal steam pilot in the 2010s. Owners should understand their barrels as manufactured by an industrial heat operation with over half a century of continuous refinement.
A Coalinga royalty is about as durable as oil income gets — the field has paid interest owners through two world wars, and steam has kept it alive for sixty years. Value today rests on lease-level activity, oil gravity in your area, and a sober view of California’s permitting environment, which constrains expansion even in long-established fields. Many Coalinga interests are small inherited fractions whose owners have never had them professionally evaluated. We do that work at no cost: we buy minerals and royalties in Fresno County and provide free written offers.
County-level well data, production charts, and selling guides for the counties this field spans:
Quite possibly. The field still produces by steam flood, and interests in active lease areas continue to pay. Even interests in currently idle areas can hold value. A check stub, old deed, or lease description lets us determine exactly what you own and whether wells are producing on it.
Operations have long been divided, principally between Chevron and Aera Energy, with Aera becoming part of California Resources Corporation in a 2024 merger. Your check stub identifies which company pays your specific interest — the essential first fact for any offer.
You send documentation — a check stub, division order, or deed. We verify title and evaluate the producing wells and operator activity behind your interest, then deliver a written cash offer. There is no fee and no obligation; many owners use the offer simply to understand what they hold.