Shirley Dutton

Shirley Dutton

Shirley P. Dutton is a Senior Research Scientist at the Bureau of Economic Geology, The University of Texas at Austin. Her technical expertise is in clastic sedimentology and reservoir characterization, and her main area of research is sandstone diagenesis. She received a Bachelor’s degree from the University of Rochester and Masters and Ph.D. degrees from The University of Texas at Austin, all in geology. Dr. Dutton has been at the Bureau since 1977. She is currently the principal investigator of the Bureau’s Deep Shelf Gas project, which is focused on structural/stratigraphic architecture and reservoir quality of deep Gulf of Mexico reservoirs.
 
lecture abstract

Lecture SD1: Reservoir quality and pore-type evolution in Tertiary Wilcox sandstones
of the northern Texas Gulf of Mexico coast during burial from 0.2 to 6.6 km

As the search for gas in the Gulf of Mexico focuses increasingly on reservoirs at depths >4.5 km, the greatest unknown and most critical risk factor is reservoir quality. Petrographic analysis of Wilcox sandstones on the upper Texas coastal plain provides insight into the evolution of porosity and permeability during burial that is useful to deep exploration both onshore and in the deepwater Gulf of Mexico. Wilcox sandstones are mostly lithic arkoses and feldspathic litharenites having an average composition of Q59F22R19. Provenance did not change significantly during Wilcox deposition in this area, nor does average sandstone composition vary among lower, middle, and upper Wilcox sandstones. However, lowstand slope-fan deposits contain more rock fragments (mainly metamorphic and volcanic) than do deposits from highstand or transgressive systems tracts. Wilcox sandstones deposited in deepwater environments in the Gulf of Mexico are likely to contain more rock fragments than do their linked highstand equivalents.

With increasing burial depth, total volume of porosity decreases, and the proportion of different pore types changes. Average core-analysis porosity declines from 35% at 0.4 km to 10.7% at 4.5 km. Pores change from a mix of primary, secondary, and micropores (P35S38M27) at shallower depths to predominantly secondary pores and micropores in deeper sandstones (P7S35M58). By 3.5 km, most primary pores have been lost by mechanical compaction or occluded by quartz cementation, and secondary pores generated by feldspar dissolution compose the majority of macropores. Average permeability decreases from 976 md at 0.4 km to 0.2 md at 4.5 km. Because most deep sandstones are dominated by secondary and micropores, the porosity-permeability transforms for deep and ultradeep sandstones will have lower slopes than those for shallower sandstones.
publications of note

Dutton, S. P., 2008, Calcite cement in Permian deep-water sandstones, Delaware Basin, west Texas: origin, distribution, and effect on reservoir properties: AAPG Bulletin, v. 92, no. 6, p. 765–787.

Dutton, S. P., White, C. D., Willis, B. J., and Novakovic, D., 2007, Calcite cement distribution and its effect on fluid flow in a deltaic sandstone, Frontier Formation, Wyoming, in Understanding Diagenetic Controls on Sandstone Reservoir Quality: A Compendium of Influential Papers: American Association of Petroleum Geologists, Getting Started, No. 4, paper No. 7, CD-ROM (reprinted from AAPG Bulletin, 2002, v. 86, no. 12, p. 2007–2021).

Dutton, S. P., Kim, E. M., Broadhead, R. F., Raatz, W. D., Breton, C. L., Ruppel, S. C., and Kerans, Charles, 2005, Play analysis and leading-edge oil-reservoir development methods in the Permian basin: increased recovery through advanced technologies: AAPG Bulletin, v. 89, no. 5, p. 553–576.

 

  
 
 
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