Florida Geological Survey


day. Production is from the Sunniland Formation
from -11,417 to -11,430 feet MSL from a leached
limestone bioherm. The faunal composition of
the bioherm is somewhat typical of the Sunniland
reservoirs (as described in the south Florida oil
fields introduction above) (Means, 1977, Mitchell-
Tapping, 1986). Mitchell-Tapping (1986)
observed faunal differences at Sunoco Felda
field which indicated formation in "the shallow
lagoonal zone of the back-reef environment."
The reservoir has a permeability barrier to the
northeast which prevents migration of the oil up-
dip (Tyler and Erwin, 1977).
 Means (1977) summarized the reservoir
characteristics of Sunoco Felda field. These
include an average pay zone thickness of 11
feet, average porosity of 18 percent, average
water saturation of 50 percent, A.P.I. oil gravity of
25', and average daily oil production of 1,700
barrels.
 As of December 1989, Sunoco Felda field was
producing from 18 wells (Appendix 3). Total
production was 11,529,000 barrels of oil
(Appendix 2).


 CORKSCREW FIELD

 Corkscrew field was discovered on November
 10, 1985 with an initial swab test of the R. K.
 Petroleum Rex Properties number 33-2 (permit
 1170). Corkscrew field is located about two and
 one-half miles north and slightly west of the one-
 well Lake Trafford field in Collier County, Florida
 (Figures 1 and 21). In its initial test, the
 discovery well produced 435 barrels of 250 A.P.I.
 gravity oil per day with no saltwater. Production
 was from open hole in the Sunniland at -11,502
 to -11,520 feet MSL.
 Core analysis by Analytical Logging, Inc. (Ft.
 Myers, Florida) indicated an oil producing zone
 from -11,506 to -11,515 feet MSL. The zone was
 described as a "fossil-hash" of dolomitic
 limestone with an average porosity of 15.25
 percent. This description, and the small closed
 structure drawn by Cheeseman (1988) (Figure


21), are again consistent with a bioherm
formation for the reservoir.
 Two successful offsets have been drilled at
Corkscrew field (Figure 21, permits 1199 and
1201A) (Lloyd, 1989). These two wells and the
discovery well were all producing at the end of
1989 (Appendix 3). Total oil production as of
January 1, 1990 was 524,000 barrels (Appendix
2).


 LAKE TRAFFORD FIELD

 Lake Trafford field was discovered by Mobil Oil
Corporation on the Baron Collier Jr. lease in
Section 9, Township 47 South, Range 28 East in
Collier County (Figures 1 and 21). The discovery
well (permit 401) was completed on March 30,
1969 (Appendix 1). During initial production tests
the well pumped 118 barrels of 25.60 A.P.I.
gravity oil and 78 barrels of saltwater per day.
Production was from the Sunniland Formation
from -11,830 to -11,892 feet MSL. The well was
later squeeze cemented to shut off water from
above the perforations. The well is unique in
south Florida in that it has not produced water
since that time.
 Lake Trafford field is also unique in south
 Florida as the only field which produces oil from
 a fractured limestone in the lower Sunniland
 Formation (Means, 1977). Core material from
 the discovery well has been described as an
 argillaceous, burrowed, limestone "rubble." The
 combination of burrowing and fracturing was
 believed to be responsible for the development of
 producible permeability and porosity (Jim
 Richter, Mobil Oil Corporation, personal
 communication, in Applegate and Lloyd, 1985).
 Offsets drilled northwest and south of the
 discovery well were dry holes. The discovery
 well remains the single producing well for Lake
 Trafford field. The well was shut-in in March
 1988 and remained shut-in for the rest of 1988
 and all of 1989. Total oil production for this field,
 as of the end of 1989 was 278,000 barrels
 (Appendix 2).