Estimating mechanical properties from sparse measured data in off shore hydrocarbon reservoirs

This paper describes an inverse problem for compaction analysis by implementing a recently developed constitutive model in 1-D simulations. The paper uses this effective constitutive model to account for strain rate dependent reservoir compaction during depletion, re-pressurization and water-flooding. By designing an inverse problem, we present a workflow to assess whether it is possible to estimate reservoir properties based on sparse measured data in off shore hydrocarbon reservoirs. To this purpose, a multi-layered reservoir model from the Dan field with various material properties under overburden stress is simulated as an objective model. The methodology is to solve an inverse problem to optimize the elasto-plastic material properties by means of history matching. The data used for the history matching process includes vertical displacement monitored with GPS survey at the top layer. By minimizing the error between simulation and objective data, the simulator optimizes the mechanical material properties of each layer such as the elastic modulus, pore collapse stress and water weakening effect with an effective procedure. It will be presented how the model matched the observed data from the field.