Kentucky Geological Survey
Abstract: Potential Natural Gas Plays Associated with Proterozoic-Cambrian Rift Basins in the Southeastern Midcontinent, U.S.A.
The deep parts of basins in the continental United States
constitute an important group of potential natural gas exploration
opportunities. These frontier plays could be a valuable national
resource, although they are currently not being vigorously pursued
by industry. One such play is the Proterozoic-Cambrian rift-basin
complex of the southeastern Midcontinent, U.S.A. Less than 0.1
percent of the wells drilled in this area have penetrated Cambrian
strata beneath the Knox Group, yet it is estimated that the
pre-Knox Cambrian succession alone could contain up to 43 trillion
cubic feet of gas. The Cambrian Reelfoot-Rough Creek-Rome Rift
System of the southeastern Midcontinent contains thick syn- and
post-rift fill sequences within fault
-bounded grabens and thinner,
but potentially productive, intervals on its flanks. Even less well
known are the underlying, complex Proterozoic rift sequences for
which meager well data indicate a dominantly sedimentary nature.
Regional reflection-seismic data for these older rift sequences
also indicate a sedimentary origin in adjacent undrilled areas.
Angular unconformities interpreted from these reflection-seismic
data show that the Proterozoic rocks may be divided into two or
more sequences. The unconformities and their associated pinch-outs
and onlaps, together with interpreted fan complexes, could be
world-class stratigraphic plays. Tilted
fault
blocks, horsts, and
large anticlines constitute several potential structural plays
associated with these rifts. These unexplored, stacked rift basins
represent a plethora of
trap
types and potential new targets for
natural gas exploration in an area crossed by a number of major
natural gas pipelines serving the northeastern United States.
AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas