A play level assessment of undiscovered resource potential

Category Other
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Cournot, Alexandra; Zater, Mustapha
Holding Date 08 September 2008

The project was carried out to quantify the undiscovered resource potential. Areas with high prospectivity were documented and illustrated to increase our understanding of the exploration potential and help to focus our efforts.
Common risk segment (CRS) maps were established for each play in each basin followed by an assessment of the yet-to-find (YTF) potential in these plays. This work provides a good technical foundation for future exploration.
In a first part, the workflow to create CRS maps will be illustrated. Six elements were assessed: the presence and quality of the reservoir, the presence of a source rock and the possible migration from the mature areas as well as the seal presence and integrity. An ArcGIS toolbox was developped to combine these different maps and build the total CRS map. The available data density and quality vary from basin to basin. The notion of confidence was integrated to show the resulting uncertainties.
The CRS maps are the basis for defining the YTF assessment areas. Depending on the available data and the geological knowledge, two alternative assessment methods were used for estimating the YTF potential.
The area yield method is based on richness or yield estimation. The richness is the ultimate recoverable resources per area unit. A geological analogue reference area is used to provide an estimate of the richness. The reference area has to be representative of the play i.e. same reservoir, source rock and trapping mechanism and is a relatively well explored area. The richness is then applied to the assessment area, i.e. where the play is believed to work. A basin will illustrate this method.
The field size distribution method is based on a more extensive knowledge of a play and requires an estimate of number of potential prospects, their size ranges and associated chance of success. The size ranges were established based on estimates of different parameters such as area of closure and reservoir and fluid properties as well as known sizes of discoveries in the play. Estimates of trap densities were used to define the number of potential prospects. Another basin will demonstrate this method.