Analysis of Pressure Variation of Fluid in Bounded Circular Reservoirs under the “No Flow” Outer Boundary Condition|
ERHUNMWUN, I.D. & AKPOBI, J.A.
Predicting the pressure at the wellbore in bounded circular reservoir has been the hub in the study of
Reservoir Engineering. Predicting the pressures outside the reservoir was not an easy task. The Ei function method has been the
only method for determining the pressure outside the wellbore of a bounded circular reservoir. The disadvantage of the Ei
function method is that it involves rigorous iterations. This study sorts to use another approach to determine the pressure within
and outside the wellbore at a glance. The finite element method was used in this study. The reservoir domain was divided into
smaller subdomains and analysed. The results from these subdomains were assembled to represent pressure in the entire
reservoir. The results obtained where shown tabular form (dimensionless pressure and dimensionless time) for dimensionless
radii of 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 9, and 10. It was shown that the relationship between dimensionless pressure and
dimensionless time was linear. The result obtained at the wellbore was compared with the results obtained by Van Everdigen and
Hurst. It was shown that there was a strong positive correlation between the results.
Bounded circular reservoir; constant terminal rate; dimensionless variables; diffusivity equation; Crank-Nicholson scheme