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Abstract: High Resolution Sequence Stratigraphy in the Upper Jurassic Carbonate Platform of the Paris Basin: Reservoir Geometries in Lagoonal, Protected Marine and Ooids Shoals Environments

Pascal Houel, Lorenzo Villalobos, Francois Guillocheau, Emmanuelle Wicquart, Monique Mettraux

Reservoir geometry reconstruction within carbonate platforms has been carried out in the Upper Jurassic of the Paris basin based on high-resolution sequence stratigraphy correlations (cores and well-logs). 18 cored wells over 25 km2 have been correlated (Saint-Clair-sur-Epte field, Gaz de France).

During lower and middle Oxfordian the Paris basin is a carbonate platform prograding southward. This progradational trend can be subdivided into three upper order sequences (parasequences sets, mean duration: one m.y.).

The lower parasequence-set is a stacking of shallowing-upward parasequences made-up of tidal ooids bars surrounded laterally and backward by more protected environments (large variety of coated grains).

The middle parasequence-set is recorded in lagoonal environments with numerous channels and lobes of storm washover-fans. Metric-thick sequences have been correlated over the field. They are emersive upward (subtidal lagoonal deposits cut by storm-induced channels and lobes, covered by small karsts).

The upper parasequence-set is made-up of protected-marine deposits grading into lagoonal sediments. The metric-thick shallowing-upward sequences are composed by sheet-shaped, strongly bioturbated, medium to coarse-grained bioclastic limestones. Correlation levels are the deepest facies (strongly monospecifically bioturbated wackstones).

Shape and size of reservoirs will be quantified.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France