Jay Field, Florida—A Jurassic Stratigraphic Trap1
The first Jurassic oil discovery in Florida was made in June 1970, in Santa Rosa County near Jay, 35 mi (56.3 km) north of Pensacola. Current estimates indicate recoverable reserves in the Smackover Formation of 346 million STB of oil and 350 Bcf of gas. The accumulation occurs on the south plunge of a large subsurface anticline, and the updip trap is formed by a facies change from porous dolomite to dense micritic limestone.
The Smackover consists of a lower transgressive interval of laminated algal-mat and mud-flat deposits and an upper regressive section of hard-pellet grainstones. Early dolomitization and freshwater leaching have provided a complex, extensive, high-quality reservoir. Irregular distribution of facies presents difficult problems in development drilling, unitization, and pressure-maintenance programs.
Hydrogen sulfide content of the hydrocarbons requires expensive processing facilities and well investment. A typical completed well costs $650,000, and an additional $200,000 is required for flow-line and inlet separation facilities. Add to this $550,000 for plant facilities to sweeten the oil for market, and each well investment approaches $1,400,000.
Daily production from Jay field is 93,500 bbl from 89 wells. The rapid development of this field resulted from a drilling program coordinated with modular plant design.