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Here we describe a fast 3D steam drive simulator. We use an interface model, where the single-phase steam zone is separated from the two-phase liquid zone by the steam condensation front ͑SCF͒ which constitutes the interface. Steady-state heat balances applied at the interface reduce the steam problem to a problem of gas/oil/water flow. Heat losses are treated by a prescribed conversion of steam to water. The model incorporates gravity, viscous and capillary forces and handles arbitrary permeability distributions and well configurations.We use a multigrid method to solve the pressure equation. The steam zone development is determined by a probabilistic method, which ensures that instability phenomena are properly treated. The oil/water flow problem in the liquid domain is solved as in conventional reservoir simulators. We validate the model with analytical models.Example calculations for a thin medium-viscosity oil field show that a transition zone with a reduced oil viscosity just downstream of the SCF has a pronounced stabilizing effect. This, and the global heat loss effects are the reason for the high displacement efficiency of steam drives.

In preparation for potential exploration success in the Lower Jurassic Posidonia shale gas play in The Netherlands, EBN decided to investigate the possibilities and conditions of a commercial shale gas development in the area concerned. To this end, a thorough inventory and cost analysis of all activities, that are needed to develop such a shale gas play, formed the basis for an assessment of the most relevant subsurface & surface as well as commercial conditions for success. Detailed evaluations of cores, logs and ditch cuttings, detailed fracture modeling, production forecasting, planning of wells, well designs, well pads and locations, evacuation routes and project scenarios (single or multiple drilling rigs) formed part of the study. Apart from the technical and commercial parameters, environmental and legal concerns needed to be addressed. The impact of the industrial activities on the physical and social environment in a densely populated area was mapped. Mitigating/impact reducing opportunities were investigated to assure legal requirements could be met in order to obtain the necessary permits from local, provincial and national authorities and to comply with European rules and regulations. Study results indicate that economical shale gas development would be feasible in The Netherlands under the applied working assumptions.