Uncertainty Analysis in Hydrocarbon Reservoir Studies

One of the main duties for reservoir engineers is reservoir study, which starts when a reservoir is explored and it continues until the reservoir abandonment. Reservoir study is a continual process in which after a period of production, the study should be updated. A reservoir study starts with gathering data (geological, geophysical, drilling and production) and then continues with building a geological model. The geological model (fine model) is up-scaled to a dynamic model and the resulted model is run by a reservoir simulator. The model results are then compared with observed (field) data. This step of reservoir study is called history-matching. If the comparisons are reasonable, the model behaves similar to actual reservoir and it is then used for predicting the future of reservoir. Because of different reasons, there are uncertainties in reservoir modeling and cause difficulties in reasonable history-matching and prediction phases of study. Quantifying and analyzing uncertainties could relief the difficulties. This book concentrates on experimental design to analyze and quantify the uncertainties. The book is divided into four chapters; in chapter one an introduction to petroleum reservoirs is presented. Reservoir modeling is discussed in chapter two. In chapter three, uncertainties in reservoir modeling and experimental design methods are explained and at last four case-studies are discussed in chapter four; three cases are run using a black-oil reservoir simulator and the fourth case is run by a thermal reservoir simulator.