Abstract: Risk & Volume Workshop for Exploration Prospects

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.

A half-day (3+ hours) workshop on Risk & Volume assessment for exploration.

Drilling an exploration wells in the search of new oil and gas fields is expensive: a well on land costs usually several million of dollars, and in the offshore several tens of millions of dollars. To justify such expenditure for drilling a new well on an exploration prospect, it is important that we assess the probability that the well will indeed find a new oil or gas field, and that we assess the volume of hydrocarbons that may be discovered.

In the workshop the participants will be introduced to the workflow that is used to assess the Probability of Success (POS) of exploration prospects, and their potential hydrocarbon volumes. The workshop includes several exercises, including an interactive group exercise assessing the POS and volumes of an exploration prospect.

Request a Visit from Jan de Jager!

Visiting Geoscientist


Jan de Jager

VU University of Amsterdam

Europe, global as funding permits


  • 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
  • 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

VG Pages