Rock mechanics related to Jurassic underburden at Valdemar oil field

The presented study is a part of the Danish Energy Research project PRIORITY - Imroved Oil Recovery and Productivity from Lower Cretaceous Carbonates.It considers a multi-disciplinary study of the Jurassic shale underlying the Valdemar structure and gives a status of the on-going research work.It has been initiated as a feasibility study of the North Jens-1 core 12 taken in the top Jurassic clay shale as a test specimens for integrated petrological, mineralogical and rock mechanical studies. Following topics are studied:(1) Pore pressure generation due to conversion of organic matter to hydrocarbon and conversion of smectite to illite implying collapse and release of interlamellar water. This is combined with studies of geotechnical deformation properties related to effective pore volume and permeability /diffusivity properties.(2) Estimation of effective pressures and possible strength and deformation properties of the clay shale using the actual core material or outcrop equivalents.(3) Flushing mechanisms for oil and gas from source rocks due to possibly very high pore water pressure creating unstable conditions in deeply burried sedimentsThere seems to be a need for integrating the knowledge in a number of geosciences to the benefit of common understanding of important reservoir mechanisms. Rock mechanics and geotechnical modelling might be key points for this understanding of reservoir geology and these may constitute a platform for future research in the maturing and migration from the Jurassic clay shale and containment of hydrocarbons in the Lower Cretaceous reservoirs.