Academic Editor: Saad A. Ragab
Copyright © 2009 Jalal Farhan Owayed and Jing Lu. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Taking a partially penetrating vertical well as a uniform line sink
in three-dimensional space, by developing necessary mathematical
analysis, this paper presents unsteady-state pressure drop equations
for an off-center partially penetrating vertical well in a circular
cylinder drainage volume with constant pressure at outer boundary.
First, the point sink solution to the diffusivity equation is
derived, then using superposition principle, pressure drop equations
for a uniform line sink model are obtained. This paper also gives an
equation to calculate pseudoskin factor due to partial penetration.
The proposed equations provide fast analytical tools to evaluate the
performance of a vertical well which is located arbitrarily in a
circular cylinder drainage volume. It is concluded that the well off-center distance has significant
effect on well pressure drop behavior, but it does not have any effect on
pseudoskin factor due to partial penetration. Because the outer
boundary is at constant pressure, when producing time is
sufficiently long, steady-state is definitely reached. When well
producing length is equal to payzone thickness, the pressure drop
equations for a fully penetrating well are obtained.