Hassan Bahrami - Reservoir Engineer, schlumberger DCS, Iran
Ali Alamatsaz - Geoscientist,Pars oil &Gas Cas Co. Iran

Layered reservoira are usually composed of layers with different characteristics separated by impermeable or low-permeability barriers such as anhydrates, shales, siltstones etc. Each layer may have different reservoir propertion from both static and dynamic standpoints. commingle well testing of reservoir layers normally does not provide individual layer parameters. Therefore, special testing techniques must bi applied to obtain the parameters of individual layers. one way of testing the wells laid in layered reservoirs involves with physically isolating each zone and performing conventional tests in each zone. This is the case when layers are explicitly separate and well recognized on formaation evaluation . In highly layered formations when the tested layer may consist of som sub-layers with internal cross-flow, this can result in a similar behavior to the one in layered formations. performing many tests at different zones is impractical and the number of reservoir zones and reservoir quality dictate how many separate tests must be conducted to properly characterize the reservoir. this paper presents a methodology in DST analysis of layered reservoirs by integrating reservoir engineering and geological interpretations on petrophysical logs. It also aims at exploring better test designs for layered formations based on which, the sought reservoir parameters can be acquired.

Well testing, Layer permeability, layered reservoir, commingle flow, radial flow, transmissivity constant