Jeffrey A. May2,
(1) Schlumberger, Denver, CO
(2) DDD Energy, Inc, Englewood, CO
(3) APEX Petroleum Inc, Denver, CO
(4) Consultant, Denver, CO
Abstract: Deep gas plays in Miocene lowstand deposits of south Louisiana
A regional sequence stratigraphic study of south Louisiana suggests that Miocene lowstand systems tract facies embody the greatest remaining exploration potential for deep, untested objectives. Recent, deep, Miocene lowstand discoveries offer proof that significant oil and gas reserves remain to be discovered in south Louisiana.
Twenty two sequences of third- and fourth-order cycles ranging in age from 21.9 MY (Cristellaria R) to 7.0 MY (Cristellaria K) are established from regional correlation of 70 chronostratigraphic surfaces. The relative position of the shelf-slope break is defined for each sequence and marks the updip extent of lowstand deposition. Depositional axes and sediment fairways are defined on the shelf to highlight associated lowstand depocenters. Thirteen of the Miocene sequences contain lowstand systems tract facies that occur in discrete, linear trends across the coastal parishes. Established production exists in the lowstand systems tract facies of each sequence.
Syndepositional fault movement and salt withdrawal created paleobathymetric lows in which basin floor and slope fan deposits accumulated. Sand-rich fan facies are best developed in intraslope basins associated with roll-over anticlines and salt withdrawal. Similarly, sand-rich delta-front facies of the prograding complex are best preserved in structural lows.
Six different play types are defined in Miocene lowstand deposits of the south Louisiana transition zone. Play trends are delimited within the context of the sequence stratigraphic framework and a regional seismic structural framework. Studies of representative fields producing from lowstand deposits provide information and interpretations that aid in predicting the characteristics of undrilled hydrocarbon accumulations within these play trends.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana