2016 – Dr. Patricia F. Allwardt

Talk abstract:

Understanding regional and local scale structure is crucial to the assessment of petroleum system risk elements during the subsurface characterization of exploration opportunities. At the play scale, crustal architecture and regional rift geometries impact the deposition of source rock, reservoir, and seal intervals; and crustal heat flows and overburden thickness impact source rock maturation and reservoir quality. Local structural evolution impacts trap configuration, reservoir presence and thickness, seal preservation and integrity, charge timing, and fetch and migration considerations. This presentation provides an overview of the impact of structural evolution on each of the petroleum system risk elements, drawing on examples from various global offshore basins. It then reviews a case study from the heavily salt modified deep water Gulf of Mexico basin.

In the Gulf of Mexico, the deposition of 40,000 to 50,000 ft of Upper Mesozoic and Cenozoic sediments above a thick (up to 15,000 ft) Callovian autochthonous salt layer, which overlies basement of varying architecture, has led to the development of a complex sedimentary basin that is punctuated by mobile salt and its remnants. Our interpretation of the salt framework reveals that salt tectonic style varies systematically across the northern Gulf of Mexico and can be spatially characterized. Within this framework, we differentiate and define domains of distinct salt tectonic style in which trap geometries and formation mechanisms are similar, and leads share common critical risks. This type of analysis provides input for where to focus exploration work program efforts.

Biography:

Tricia Allwardt is a structural geologist with ConocoPhillips in Houston, TX. She received a B.A. in earth and planetary sciences from Harvard University and a Ph.D. in structural geology and geomechanics from Stanford University. Since joining ConocoPhillips in 2006, she has spent 4 years working on worldwide reservoir structure and geomechanics projects in Technology, and 6 years in Exploration contributing to the Gulf of Mexico, Nova Scotia, and Newfoundland exploration programs. Tricia is currently transitioning to a position in ConocoPhillips’ Eagle Ford Development organization. She is an AAPG, EAGE, and HGS member and has served as an Associate Editor for the AAPG Bulletin since 2010.