Exploration with a Pedigree - A New, Practical Approach to Play and Prospect Assessment

Koller, Glenn R.; Levy, Thomas M.
SIS, Schlumberger, Tulsa, OK.

A new, practical methodology has been developed that integrates petroleum-system-element play fairway maps with creation of play-element chance maps. Play level maps can be integrated into a prospect assessment method that calculates probabilistic volumes and chance of success in the same process.

First, play fairway maps of physical elements of the petroleum system are transformed into chance maps. Element chance maps are then combined to yield a map of overall chance of success for a play, with data and interpretations stored for audit or revision. Petroleum system element play chance maps related to specific prospective areas can be passed seamlessly to a complementary and game-changing prospect-assessment application.

In conventional prospect-assessment processes, chance of failure (COF) for any parameter is disconnected from the play assessment and from parameter-specific expression of uncertainty. This approach links a prospect's geological chance of success (GCOS) to the play analysis and ties individual-parameter COFs to the distribution used to express parameter uncertainty.

The state-of-the-art distribution builder can utilize parameter- or map-information to establish uncertainty bounds and facilitates distribution shaping based on geological knowledge. It eliminates the need to select any distribution type (lognormal, beta, etc.) or to supply any statistical input. Linking uncertainty to parameter COF avoids the problem of GCOS erosion resulting from conventional disconnected-from-uncertainty estimates of COF and from an increase in the number of COF-bearing parameters.

The aforementioned linkages may be incorporated in a Monte Carlo process that produces volume estimates that represent only geologically successful prospects. Economic limits can be imposed to yield estimates of economic success. Probability-weighted volumes for use in prospect ranking are generated as are volumes used for planning development scenarios.

Individual calculations can be combined to yield multi-segment prospects or portfolio summations. This new and practical approach to play and prospect assessment is facilitated by a duo of applications designed for use by all geoscientists. Resulting from this process is a prospect assessment with a pedigree. Any results from the play or prospect evaluations are linked back to original maps. Updating of maps is reflected automatically in play and prospect assessments.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012