Abstract
The history of closed-loop seismic reservoir monitoring (CL-SRM) dates back to early 2000's with the History Matching Using Time Lapse Seismic (HUTS) project; the authors noted at the time that the proposed forward modelling step was too costly (Gosselin 2003).
From 2003 the technologies used in the forward modelling step of the CL-SRM workflow have developed in line with the availability of computing resources. Three groups of methods are currently in common use: a) direct analytical transformation of reservoir properties to seismic properties, b) variations on well log based fluid-substitution and petro-physical modelling, and c) simulation-to-seismic modelling (Gjøystdal, 2007). Both a) and b) are typically 1D and neglect realistic noise, overburden and acquisition configuration effect, while c) models noise free seismic data attributes, incorporating overburden and acquisition configuration effects via ray-tracing, but still neglects realistic noise. In all three cases the modelling is largely confined to the reservoir interval. More recent advances in computer architecture have now enabled large-scale finite difference acoustic and elastic modelling.
In parallel, research increasingly indicated the 4D-response associated with production was not restricted to the reservoir, but radiates into the over-burden, side-burden, and under-burden driven by geomechanical effects. Consequently to robustly predict a 4D-response related to production, field-scale modelling has to fully describe the acoustic and elastic response to both reservoir and field-wide changes. This complex interaction incorporates the reservoir dynamics component - which encompasses fluid properties, fluid flow characteristics, field performance history and pressure distributions and profiles over time, and also the changes in stress induced by the pressure changes during production. It is the stress changes that induce strains and deformations not only within the reservoir but also around it. Understanding the complete reservoir dynamics is not possible from studying the individual geologic, reservoir simulation, and reservoir geomechanical models in isolation – it requires they be integrated into a full-field coupled Dynamic Integrated Earth Model (DIEM)
