Selim S. Shaker, PhD

Selim S. Shaker is Director of and Consulting Geologist for Geopressure Analysis Services Inc. ( He received a B.Sc. (honor) in Applied Geology, and an M.Sc and Geology from ASU, Egypt. He also received a diploma in Hydrogeology from Prague University (UNESCO).
With over 30 years in the oil industry, he started his career in Egypt as a well-site, stratigrapher and structural geologist. During his 20 years of domestic service with Phillips Petroleum, his main function as Exploration Geologist was prospects generation in offshore Gulf of Mexico and onshore coastal areas. He discovered and developed several fields, and also evaluated several exploration projects in NW Australia, Libya, Algeria, the North Sea and China.

After retiring from Phillips in 2000, Dr. Shaker established G.A.S. to focus on evaluating the implication of geopressure compartmentalization, seal integrity and salt interaction on leads and prospects on the Shelf and Deep Water of the Gulf of Mexico. Pre- and post-drilling risk assessment of a prospect is his specialty. As a pioneering geoscientist, his recent domain is building the geological foundation for pore pressure prediction. He has been the first to recognize:

  • The optimum seismic velocity for pore pressure prediction.
  • Geopressure transgression and regression due to compartmentalization.
  • Supra and subsalt geopressure models
  • The disparity between predicted pore pressure and measured pore pressure.
  • Pitfalls of converting PP from psi to ppg mwe in reservoir rocks.
  • The qualification of centroid phenomenon in the subsurface geopressure.
  • His new method of NCT (normal compaction trend) calculation that eliminates serious mistakes and mishandling of pore pressure prediction modeling.


Dr. Shaker is the Co-Chair of the AAPG Deep Water Workshop. He is an active member of AAPG, SEG, HGS, GSH, and American Association of Drilling Engineers (AADE). He has published over 40 papers and articles regarding pore pressure predictions and the impact of geological settings on subsurface geopressure profile and risk assessments

Dr. Shaker teaches the following courses: