Programme TAPSS 2000

Coordination du programme TAPSS 2000 (Transferts Actuels et Passés dans un Système Sédimentaire aquifère-aquitard: un forage de 2000 m dans le Mésozoïque du Bassin de Paris)

Le programme TAPSS, dirigé par Maurice Pagel, a pour but de coordonner le programme de recherche sur le forage profond EST433

As part of its research programme for a radioactive-waste disposal site in Meuse/Haute Marne, Andra (France’s National Radioactive Waste Management Agency) has achieved a deep (2000 m) borehole aimed at investigating the full Mesozoic sedimentary column of the Paris Basin (down to the base of Triassic). The borehole, with a wide range of associated well logs and coring of the different stratigraphic levels, represents an excellent and rare opportunity for a multi-facet study of an aquifer-aquitard sedimentary system. Although aquifers have been extensively studied, studies of aquitards are relatively rare. The genesis of such a system begins during sedimentation and depends on the paleoenvironmental conditions, the climate and the geodynamic evolution. The Andra borehole will provide a unique opportunity to study the development of Mesozoic sedimentation through direct observation from cores and cuttings and along with a host of data from the core logs and from solution- and gas-extraction analyses. Furthermore, 2D seismic profiles have been run over an area of about 250 km², some even with a specific offset in relation to the borehole —a rare opportunity for the academic community that is unlikely to arise again for a long time. Accordingly, almost 30 laboratories from the Universities and the CNRS (French National Center for Scientific Research), BRGM (French Geological Survey), IFP (French Petroleum Institute) and IRSN (French Institute of Radioprotection and Nuclear Safety) have committed themselves to an extensive joint research programme into solution and gas transfer within a sedimentary aquifer-aquitard system. They will associate a wide range of complementary approaches, including a) paleoenvironmental and paleolandscape characterization, b) the geological, thermal and diagenetic (fluid-rock interaction) histories, c) the petrophysical properties of the rocks, d) analysis of the present thermal regime and e) a microbiology and biogeochemistry investigation.