Analytical modeling of composite and layered reservoir systems

Analytical modeling of heterogeneous reservoir systems is an important aspect of reservoir engineering and formation evaluation. Numerous analytical models have been presented in recent years to describe pressure and rate behavior of special heterogeneous systems. Composite and layered reservoir systems are two important types of heterogeneous systems frequently encountered in petroleum reservoirs.; The first objective of this research was to develop analytical models of both the composite and layered reservoir systems and to use the models to study the rate and pressure characteristics of these reservoirs in the presence of varying wellbore and reservoir parameters. The second objective was to analyze both pressure transient and production data with these analytical models using an automatic parameter estimation technique. The results presented in this dissertation show that the above objectives were fully achieved.; The first major contribution of this research to the petroleum industry is the development of analytical models of both composite and layered reservoir systems with combined effects of skin, wellbore storage and phase segregation. The second major contribution is the capability of the new layered reservoir model to handle unsteady state interlayer crossflow in addition to stratified flow. The third major contribution is the combination of an automatic parameter estimation algorithm with the analytical models for analyzing both pressure transient test and production data. No published analytical model of composite and layered systems to date has all these capabilities.