ABSTRACT

The best development of the Brown Dolomite onshore is in Charlotte and surrounding counties in the northern part of the South Florida Basin at a depth of approximately 12,000 ft (3658 m). The Brown Dolomite Zone attains a maximum thickness of 100 ft (30 m), of which one half is usually porous and capable of high volume fluid production. Offshore the maximum thickness occurs near the Marquesas Keys, where approximately 400 ft (122 m) of mostly porous dolomite has been encountered.

To date very little oil staining has been found in the Charlotte County area, but the two Marquesas wells have shown some oil staining.

The best possibility for finding oil in the Brown Dolomite appears to be in the offshore portion of the South Florida Basin. Brown Dolomite is present in at least three wells on the Sarasota Arch and probably continues around the rim of the basin to the Marquesas, where thick, porous, vugular dolomite is present. This dolomite is capped by dense limestone and anhydrite and stratigraphic and structural traps associated with it could lead to the presence of giant oil fields.