System simulation and reserves computation for a kind of gas reservoirs

Abstract

This paper studies the realization of system simulation and its application in the computation of reserves for gas reservoirs with carbonate matrices. This kind of reservoir has an important role in gas production. It is well-known that geological structures of the reservoirs are very complicated and heterogeneous and their physical properties vary with spatial position. In engineering, since the corresponding variables, as the functions of space coordinates, are not known apart from the measured values at wells, the computation of reserves presents great difficulties and its results are not reliable. This does not suit the needs of gas development. By considering the main geologic characteristics of the reservoirs, we research all relevant approaches to system simulation, improve the Barenblatt models with ideal ‘duality’ and extend them to a kind of block structure permeable model for double porosity medium systems with discontinuity. We discuss the target and content of computer simulation and the algorithms and procedures for the two kinds of double porous models. We illustrate that computer simulation is realizable and its result is applicable to the computation of reserves through three examples of real reservoir. In summary, we build up the different structural models, point out the importance of structure simulation and apply them to the real reservoirs. This is an attempt to apply distributed parameter system modeling and simulation within the petroleum engineering field.