About This Item
- Full text of this item is not available.
- Abstract PDFAbstract PDF(no subscription required)
Share This Item
The AAPG/Datapages Combined Publications Database
Houston Geological Society Bulletin
Abstract
Abstract:
Trap
Types vs. Productivity of Significant Wilcox (Early Eocene) Gas Fields in the
Listric Growth
Fault
Trend of South Texas and the Divergent Origin of Its Two Largest Producers
![Previous Hit](/data/images/arrow_left.gif)
![Next Hit](/data/images/arrow_right.gif)
![Previous Hit](/data/images/arrow_left.gif)
![Next Hit](/data/images/arrow_right.gif)
By
Wilcox Exploration Enterprises
Detailed mapping and analysis of 23
Wilcox fields in the subject trend indicate
that gas production is related to trap
type.
Of the total cumulative production of 3.5
TCFG, approximately 67% is from
upthrown
fault
blocks, implying very effective
fault
seals due to down-faulted shale
juxtaposed against gas reservoirs, differential
pressures, and probable clay smears.
NE Thompsonville and Bob West fields have produced 650 and 200 BCFG, respectively, with 400 BCFG remaining reserves in the latter. Traps of these fields are not attributed to listric growth faulting, as is suggested by their trend location.
NE Thompsonville is a 9-milelong (14.5 km) turtle structure that originated through depositional loading of an upper slope basin, followed by tilting, and eventual collapse of a sediment squeeze-up mound due to gravitational instability. These events provide an excellent example of basin evolution through sediment loading accompanied by evacuation of a salt substrate; the basin flanks are defined by basinward-dip ping listric faults that accommodated subsidence and merge beneath its floor.
Bob West field lies along the edge of the
Laramide fold belt. The 1.5 by 4 mile (2.4
x 6.4 km) field anticline adjoins a deep-seated
fault
that slices over and across a
buried structural ridge of probable Cretaceous
age. Uplift of the latter, immediately
following deposition of more than 23
stacked, shelf-bar producing sands,
upwarped the
fault
plane and resulted in
rollover growth of the Wilcox anticline.
The
fault
does not show the downward decrease
in dip that is typical of listric growth
faults. NE Thompsonville and Bob West
fields both produce upthrown along crestal
faults.
This analysis indicates that "high side" closures, irrespective of diverse origins, have achieved head-of-the-class stature as Wilcox gas producers.
End_of_Record - Last_Page 12---------------