ZIMMERMAN R. K.
Basin Research Institute, Louisiana State University, Baton Rouge, LA

Abstract: A Potential Louisiana Haynesville-Cotton Valley Pinnacle Reef Trend Predicted from Palinspastic Reconstructions

There were many late Jurassic and subsequent geologic factors that contributed to the evolution of a potential Haynesville-Cotton Valley trend of pinnacle reef development in Louisiana. Regional palinspastic reconstructions, through simulations of the structural-stratigraphic and thermal history, provide a basis for integrating several of the prime factors and predicting the most favorable area for pinnacle reef occurrence. Concentrated 3-D seismic surveys appear to remain as the most important viable option for defining individual pinnacles.

Primary requisites for pinnacle development included a suitable substrate and a conducive environment of deposition. Perpetuation of the same depositional environment over a period of several million years was essential. Finally, a postdepositional thermal history favorable for providing maturation of adjacent and underlying source beds, plus accumulation and final preservation of hydrocarbons within the reefs, was a necessity.

An analysis of well data from north and central Louisiana suggests the most likely favorable trend for pinnacle reefs, having potential commercial value, extends over an area averaging approximately 20 miles (32 km) in width and 100 miles (161 km) in length. The predicted trend extends from the Sabine uplift on the west to the LaSalle arch on the east and contains a central segment with several piercement salt domes. Updip and downdip limitations of the trend appear to be controlled by source rock factors of permeability barrier inadequacy ("too much sand") and over maturation ("too much heat"), respectively.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas