Matt, Veit1, Renaud Bouroullec1, Paul Weimer1, John
(1) University of Colorado, Boulder, CO
ABSTRACT: Regional Maturity Patterns of the Tithonian and Turonian Source Rocks in the Northeastern Deep Gulf of Mexico
The regional trends in maturity of the Tithonian and Turonian source rocks are presented for the Mississippi Canyon and Atwater Valley protraction areas, northeastern deep Gulf of Mexico. The area is an active exploration province, which is characterized by a complex stratigraphy, tectonics, and salt-sediment interaction. Fifty fields and discoveries are present in the study area.
The three-dimensional petroleum systems study is based on a grid of 141 by 166 one-dimensional simulations. The stratigraphy and lithologies are derived from a two-dimensional seismic data set (19,557 mi2), tied to 150 exploration wells and biostratigraphy. The time-depth conversion of the seismic is based on a single average interval velocity-TWTT function, where the salt intervals have a velocity of 14,600 ft/sec. The source rock parameters and boundary conditions, i.e. basal heat flow, paleo-seafloor temperature, and paleo-bathymetry, are derived from literature. The simulations are designed to investigate the regional trends and maturity history of the Turonian and Tithonian source rocks. In addition, select fields are evaluated and compared with the model results.
Overall, the maturity of the Tithonian and Turonian source rocks increases with decreasing water depth, ranging from immature in the abyssal plain to overmature on the shelf. These regional patterns of maturation are a function of the stratigraphic overburden and the basal heat flow history. However, the presence of shallow allochthonous salt systems causes local highly variable maturity, with lower values below the salt.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.