Assessment of Production Predictability of Fourth Order Systems Tracts in the Miocene Offshore Louisiana

By

Rassi, Claudia

John A. and Katherine G. Jackson School of Geosciences, The University of Texas at Austin, Austin, TX

Reservoir properties and production performance, integrated into a firm sequence stratigraphic framework have been assumed to be controlled by their position in this framework and the systems tract they are representing. This hypothesis has been tested in a dataset from two mature oil and gas fields, located ten miles offshore Louisiana. Supported by digital well log data, 3D seismic, sidewall core data and a complete production information package the systems tracts of fourth order sequences were scrutinized. The Miocene work section encompasses 58 fourth order and 10 third order sequences. As a result of this research the three systems tracts of this framework, lowstand (LST), transgressive (TST), and highstand (HST), show different but characteristic trends in porosity, permeability and production rates, which in turn can be used to predict potential hydrocarbon production performance. The LSTs of this dataset are dominated by the highest average porosity and permeability values, followed by HSTs and TSTs. The production rates of the HSTs are highest, followed by LSTs and then TSTs.

A comparison of the rock or production properties of the subunits of fourth order sequences to third order shows that latter have different trends, which are not similar to the characteristics of fourth order systems tracts. The final product of this research is a database, which allows the user to search with different criteria, manifested in various query setups. This database includes the rock properties, the production output and facies description for every system tract that has been producing.