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Oklahoma City Geological Society invites you to their event

May Technical Luncheon - Dr. Jeff A. May

About this event

"Using Sequence Stratigraphy to Optimize Target Selection in Unconventional Reservoirs”

Jeff A. May, PhD

Chief Geologist (Retired), EOG Resources & Affiliate Faculty, Colorado School of Mines


Sequence stratigraphy is not THE answer in optimizing the selection of horizontal targets in unconventional reservoirs. But it is an extremely useful, and oftentimes necessary, tool that should be used when defining sweet spots and evaluating reservoir intervals.    

Sequence stratigraphy can aid subsurface geologic interpretation and evaluation in numerous ways. It (1) provides an increased understanding of depositional controls on reservoir vs. non-reservoir facies, (2) promotes better well-log correlations, (3) aids in reservoir prediction, (4) offers a framework for data integration, (5) guides sample collection from core, (6) delivers better reservoir flow models and volumetric calculations, (7) helps in choosing and staying within the target zone, and (8) furnishes input for completion design.

This talk focuses on four aspects of optimizing horizontal targeting based on sequence stratigraphic concepts. First, the importance of establishing accurate correlations based on flooding surfaces and parasequences when selecting a target and landing the wellbore is demonstrated for the Baxter and Parkman sandstones. Second, the significance of compartmentalization relative to reservoir modeling and economic evaluation in highstand vs. falling stage systems tracts is described for the Viking, Woodbine, Sussex, and Frontier-Turner systems. Third, identifying different types of erosional surfaces and their impact on hydrocarbon production and placement of laterals are highlighted for the Frontier-Turner and Bakken formations. Finally, the prediction of optimum reservoir and mechanical properties, i.e., large, interconnected pores in strong and brittle intervals, within a sequence stratigraphic framework are revealed for the Marcellus, Eagle Ford, Mowry, Niobrara, and Avalon (Leonard) shales.


Jeff received his B.A. in Geology from Earlham College, M.S. in Geology from Duke University, and Ph.D. in Geology from Rice University. He has worked in the oil and gas industry for 40 years: as a research geologist with Marathon Oil Company (1981-1994); as a geological and geophysical consultant with Enron Oil & Gas (1994-1996) and GeoQuest Reservoir Technologies (1996-1998); as an exploration geoscientist with DDD Energy (1998-2001); and with EOG Resources beginning in 2001, first as Chief Stratigrapher and then as Chief Geologist, until his retirement in 2011. He now is a geologic consultant and an Affiliate Faculty member in the Department of Geology and Geological Engineering at Colorado School of Mines.

Jeff has conducted sedimentologic, sequence stratigraphic, and seismic stratigraphic projects on basins and fields worldwide. Areas of expertise include onshore and offshore Gulf of Mexico; onshore and offshore California; Uinta, Green River, Washakie, Denver, Powder River, Permian, and Williston Basins; northern and eastern Egypt; and Natuna Sea, Indonesia. He also leads a variety of classroom and field seminars on clastic facies, deep-water sandstones, sequence stratigraphy, and mudrock deposition and stratigraphy, most notably for the American Association of Petroleum Geologists, the Petroleum Technology Transfer Council, Nautilus Worldwide, many oil and gas companies, and universities. His publications encompass numerous papers and abstracts on deep-water sandstones, sequence stratigraphy, geophysical interpretation, and mudrock deposition. Jeff has twice been presented the best luncheon speaker award by the Rocky Mountain Association of Geologists, was presented the Frank Kottlowski award for best speaker in the Energy Minerals Division at the AAPG annual convention in 2012, completed an AAPG Distinguished Lecture tour, and received the Outstanding Scientist Award from RMAG in 2017. 

Hosted by

  • Guest speaker
    JM G
    Jeff May Affiliate Faculty @ Colorado School of Mines

  • Team member
    Okc Geological Society

Oklahoma City Geological Society

Oklahoma (/ˌoʊkləˈhoʊmə/) is a state in the South Central region of the United States, bordered by the state of Texas on the south and west, Kansas on the north, Missouri on the northeast, Arkansas on the east, New Mexico on the west, and Colorado on t...