Using influence diagrams to analyze decisions in 4D seismic reservoir monitoring

Exploration and production decisions are complex due to several uncertainties: uncertainty in the geologic properties, seismic imaging, repeatability, reservoir structure, rock and fluid properties, etc. Furthermore, several decisions need to be made over the entire life cycle, and often it is not clear how current decisions might affect the future bottom line. In the exploration and characterization stage, more information is acquired about the reservoir structure, reservoir rock and fluid properties, and the spatial distributions of lithology, porosity, and saturations. Exactly how much information needs to be acquired is a critical decision at this stage. Later, decisions have to be made about the technical and economic feasibility of seismically monitoring the reservoir during production. Simple tools like decision trees have become popular (e.g., Newendorp and Schuyler, 2000) but complex situations demand the use of more sophisticated decision-analysis tools and their integration with the existing to...