Vertical permeability, often a key parameter in reservoir engineering, can be calculated from the analysis of a limited entry pressure transient. Analytical solutions for limited entry welltests, where a fraction of the reservoir interval is perforated, have been available in the literature for some time. This paper considers the evaluation of limited entry welltests in heterogeneous layered formations. A number of field examples have been analysed using both conventional analytical techniques and a new general purpose numerical welltest analysis application. The examples show that in layered formations vertical permeability can be significantly under estimated by conventional analytical analysis.

Keywords:
horizontal permeability, geometry, upstream oil & gas, wellbore storage, perforated interval, application, thickness, regime, grid, perforation
Subjects:
Well & Reservoir Surveillance and Monitoring, Reservoir Characterization, Reservoir Fluid Dynamics, Reservoir Simulation, Formation Evaluation & Management, Information Management and Systems, Flow in porous media, Pressure transient analysis, Drillstem/well testing
Copyright 1994, Society of Petroleum Engineers
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