Print this pageReservoir Characterization and Simulation Using Outcrop Observation and Geostatistics: A North Sea Analogue Case Study
We present a multidisciplinary methodology that integrates outcrop observations, reservoir simulation and geostatistics to evaluate the reservoir potential of geological formations. We apply this methodology to fluvial strata of the Middle Jurassic Ravenscar Group, using outcrop observations that were obtained during a fieldtrip to the Yorkshire coast in the UK. The evaluation of these channelized fluvial sandstones is particularly relevant due to them having characteristics analogous to the Ness and Pentland Formations, productive hydrocarbon reservoirs in the Viking Graben and Central Graben provinces of the North Sea. A significant problem with these reservoirs is their low recovery factor, hence we proposed an integrated reservoir characterization methodology that allows us to improve the description of such complex reservoirs using analogous outcrop information. In the first part of this work a numerical simulation model is built based upon outcrop observation, available logs and petrophysical data measured in the laboratory using samples obtained in the field. In the static properties we include geometry, petrophysical properties, vertical and horizontal extensions based upon outcrop information. The fluids and dynamic properties used in the simulation model correspond to a North Sea producing reservoir associated with a water flooding process. This resulting simulation model allows us to gain an initial evaluation of reservoir potential for channelized fluvial strata analogous to the Ness and Pentland Formations. In the second part of our work we generate stochastic realizations based upon the outcrop observation using Sequential Gaussian Simulation. We present and discuss the geological and numerical results comparing the performance, of the initial model and the stochastic models. In this work we integrate in a multidisciplinary workflow geologic observation and reservoir simulation to evaluate the potential of fluvial formations from the North Sea Basin, considering the associated uncertainty by using geostatistics to describe channel distributions. The resulting ensemble allows us to evaluate the dynamic behaviour of a system with similar properties to the Ness and Pentland Formations. Our final integrated model can be used as a base model to make decisions about future development plans in equivalent formations, resulting in improved productivity of the reservoir and an increased recovery factor.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil