The Champrose field produced, from 1991 to 1997, a total of 27,651 tn of oil in the Keuper sands. The field was discovered in 1990 on “La Marsange” licence. The CHO-1 discovery well started producing anhydrous oil in February 1991. Water cut increased up to 49.8 % in December 1991 after production of 10,855 tons of oil. CHO-2D appraisal well, drilled in September 1991, was not successful and was transformed to an injection well with rates that attained 64 l/day at the end of the same year.

Among 16 drilled wells within the block, 7 had oil shows and 2 produced. Several 2D seismic crews were shot between 1976 and 1989 totalizing more than 700 km of useful seismic data. Total OIP for both sands and dolomites rises up to 2.3 to 2.5 MMBO for 185 MBO recovered already.

Reservoirs : Upper Dogger oolithic limestones are good reservoir rocks in the Villevaude area with portosities up to 11%. Both the Grès de Chaunoy and the Grès de Donnemarie (Upper Trias) are well represented, however with low porosities of around 6%.
Source-rocks : The main source rock is the Liassic shales. Migration begins in Late Cretaceous with hydrocarbons moving upward in the oolitic limestones of Upper Dogger (Callovian - Bathonian). Minor source rock is considered to be Pre-Triasic shales providing oil that migrated at a later time in the Chaunoy and Donnemarie sandstones.
Seals : Callovian and Keuper shales.
Traps : They are structural, developing mostly in grabens. Some stratigraphic traps appear to be Pre-Triasic channel infills.