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Numerical Basin Modeling – A Case Study from the Jeanne d’Arc Basin, Offshore Eastern Canada

Friedemann Baur1, Ralf Littke1, Hans Wielens2, Rolando di Primio3, and Carolyn Lampe4
1RWTH Aachen University - Institute of Geology and Geochemistry of Petroleum and Coal, Aachen, Germany
2Geological Survey of Canada (Atlantic), Bedford Institute of Oceanography (GSC-A BIO), Dartmouth, Nova Scotia, Canada
3Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum – GFZ, Potsdam, Germany
4UCON Geoconsulting, Cologne, Germany

Petroleum systems modeling in 4 dimension (space + time) predicts hydrocarbon generation and migration as well as the quantity and quality of accumulated hydrocarbons in reservoirs, taking temperature, maturity, compaction, overpressure and other parameters into account throughout the entire evolution of the basin. A Petroleum Systems Model thus provides the only means to integrate all physical aspects (source, trap, seal, and reservoir) and time (charge) to quantify and analyze processes and, hence, reduce exploration risk. Therefore, it is also the best tool to provide a reasonable resource assessment.

Over the last years, modeling technology has advanced so far that the basin-model results appear to approach reality. However, very little is known about possible migration pathways in basins worldwide where no basin modeling studies have been applied. Additionally, not much information has been determined and published on how much of the generated hydrocarbons are preserved through time, how much is lost and under what conditions. Therefore, it is crucial to quantity and mass-balance the generated, expelled and accumulated hydrocarbons both by measuring and modeling. For this, one ideally needs a confined basin/oil field charged by one source rock and/or kitchen area where the petroleum did not migrate away from the basin/prospect. The Jeanne d’Arc basin seems to meet all these requirements and is therefore ideal to study constraints and effects on migration history and required input and output parameters for a model, as compared to reality.
The Jeanne d’Arc Basin, offshore Newfoundland, containing Hibernia, Terra Nova and White Rose oil fields, was formed as a failed-rift basin, which was initiated in the Triassic and is shaped as a V, deepening and opening to the north, filled with sediments to a depth of over 20 km. Evaporites formed during the initial Triassic rifting, limestones and fine clastic rocks were deposited during a quiet period (Jurassic) and coarse clastics interbedded with shales (reservoirs, seals, source rocks) during the Cretaceous and Cenozoic.

The Hibernia Field is one area of the basin where faulting and folding formed hydrocarbon traps. This field is complicated by the formation of reservoir compartments, whereby some may have strong, while most have moderate overpressure. In Terra Nova Field, oil is preserved mainly by stratigraphic traps; additionally, slightly different oil-water contact-depths show that at least some of the compartments are not in communication. The Whiterose oil field is fault-bounded and structurally controlled.

Our integrated basin modeling approach uses the best available input data and PhaseKinetic models, especially measured on the Egret Member source rock, for hydrocarbon generation and phase-equilibrium modeling. Many different additional calibration data (well-, rock and fluid-data) such as porosity, permeability, temperature (bottom hole, apatite fission tracks, fluid inclusions), maturity (vitrinite reflectance), API, GOR, Bo (Formation Volume Factor), and Psat have been incorporated.
The results of this geochemical petroleum system modeling study shows new concepts in basin formation and identifies migration pathways especially for the Terra Nova oil field to explain the only possible and correct filling history, considering also compartmentalisation through faulting. This new migration concept differs from traditional explanations based on geochemical measurements only. Additional we will show that mass balance calculations are crucial when determining the probability of a successful hydrocarbon charge and can replace in some cases complex migration models.

 

AAPG Search and Discovery Article #90091©2009 AAPG Hedberg Research Conference, May 3-7, 2009 - Napa, California, U.S.A.