Jan de Jager

Jan de Jager

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Jan de Jager studied geology at the University of Utrecht. In 1979 he completed a PhD on the relation of turbidite sedimentation and tectonics in the Northern Apennines, following which he joined Shell as an exploration geologist. He had overseas assignments on many continents and in a variety of positions. In his last years with Shell he was senior advisor to Shell global management on Exploration opportunities, manager of the Exploration Excellence Team and Principle Technical Expert for Risk & Volume assessment for exploration.

In 2010 he retired from Shell and took up a part-time position as professor petroleum geology in the Netherlands (Shell chair) and as visiting professor at the University Malaya in Kuala Lumpur. After the summer of 2015 these university commitments came to an end and currently he keeps himself busy with consultancy to several companies, providing courses on exploration-related topics (Play-based exploration, Prospect Maturation, Risk & Volume assessment) and occasional university lectures.



  • 16495 A 1 hour presentation on some of the issues that tend to generate discussions for Risk & Volume assessments: column length prediction, what are we risking; mixed oil-gas prospects, multiple reservoir-seal pairs, geophysical evidence (DHIs), Play POS, ineffective reservoirs, etc. Recommendations on how to deal with these issues will be given. Hot Topics in Risk & Volume Assessment
    Hot Topics in Risk & Volume Assessment
  • 16494 A half day (3 hours or so) workshop on Risk & Volume assessment, whereby the participants will be introduced to Risk & Volume assessment and actually do a risk assessment and volume calculation for an exploration prospect. Risk & Volume Workshop for Exploration Prospects
    Risk & Volume Workshop for Exploration Prospects
  • 16496 A 1 hour presentation. The distribution of oil and gas in subsurface hydrocarbon accumulations is in the first place strongly controlled by the types and maturities of source rocks that have generated the oil and gas. Sealing lithologies above the reservoirs (generally shales, tight carbonates or evaporites) prevent hydrocarbons from escaping to the surface. The role that these seals play in the distribution and relative quantities of trapped oil and gas is often understated. Seals are rarely perfect. Except for salt, most seals have some porosity and permeability allowing hydrocarbons to slowly leak out of the trap. Even at geological time-scales this leakage of hydrocarbons out of traps can be a very slow process. When the rate of leakage is less than the rate of charge, seals may appear effective. But there is a wide range of lithologies ranging from very good seals to non-seals. Ductile and fine-grained lithologies are the best seals. Sealing potential is less for lithologies that are more brittle, and/or more silty or sandy. Faults and fractures may be preferential leak paths, further compromising the effectiveness of seals. In areas of gas charge any (early) oil charge should normally be displaced by the lighter gas accumulating at the top of structures. The observation that in areas of abundant gas charge also oil may nevertheless be trapped, indicates that gas may leak out of traps preferentially – thus making room for oil. This notion should be seriously considered in predictions of the phase of trapped hydrocarbons in undrilled prospects that may have has access to both oil and gas charge. In the presentation examples will be shown of the dynamic nature of leakage and charge and of structures where oil has been trapped, despite abundant gas charge. The Role of Seals in Oil and Gas Entrapment
    The Role of Seals in Oil and Gas Entrapment

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