AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Sonic Velocity Analysis of Triassic and Paleozoic Interval of Onshore North Florida Wells to Determine Exhumation
(1) Shell, Houston, TX.
The geologic history of North Florida has been strongly influenced by major tectonic events such as the formation of the Pangaean super continent and the subsequent plate reorganization. Correlation of the Paleozoic sediments in Florida with North Africa have led most researchers to suggest that Northern Florida was a part of Gondwana. Analysis of well data in Northern Florida shows that the Lower Ordovician to Devonian sediments were deposited in a continental to marine silicicastic environment at the continental margin indicative of significant source rock potential. Current models suggest accretion of North Africa, of which North Florida was then a part, to North America during the Devonian. Since most producing basins in present day North Africa are sourced by Silurian and Devonian shales, there is a significant possibility that analogous source rocks would be found in the Paleozoics of Florida. The hurdle is to determine maturity and structural context of this interval regionally.
In this work, the Magara Sonic log technique has been applied to the sonic shale velocities of the Triassic and Paleozoic sections in Northern Florida to constrain the extent of compaction and estimate the amount of erosion and uplift in this region after correcting for the temperature effects due to igneous intrusions. Integration of the sonic shale velocities with the temperature logs, dipmeter data, cores, and available seismic data helps correlate the timing and extent of uplift in the Paleozoic to the timing and extent of ongoing suture zone tectonics of this region. The study suggests that the suture zone effects could have extended further south than previously suggested. The differential burial history could have siginifcant implication on source rock maturity of the Silurian and Devonian shale of onshore Florida.