ABSTRACT
This paper presents the parametric behavior of a constant pressure well in the center of a two-composite reservoir with wellbore skin. For infinite composite reservoirs, the effects of mobility ratio, storativity ratio, wellbore skin, and the discontinuity distance on rate decline and cumulative influx are described. For bounded reservoirs, the effects of the outer boundary distance are presented. Type curves for the dimensionless wellbore flow rate in both infinite and bounded composite reservoirs are provided. These type curves are to be used for log-log type curve matching. An analysis method that comprises conventional semi-log analysis and log-log type curve matching to determine the dimensionless variables is proposed, and is tested and demonstrated with simulated data.
Rate decline and rate decline derivatives of a constant pressure well are presented for infinite, constant pressure outer boundary, and closed outer boundary homogeneous reservoirs. A rate derivative type curve is provided for these cases as well. This type curve complements the rate decline curves presented by Fetkovich. The effects of the dimensionless reservoir exterior radius are discussed. Rate decline and rate decline derivatives of a constant pressure well in an infinite composite reservoir are also presented. For composite reservoirs, the effects of mobility ratios and discontinuity distance on both rate decline and rate decline derivatives are presented. Type curves for dimensionless wellbore flowrate derivatives for infinite composite reservoirs are provided. A new correlating group for the derivative type curve is provided, and is different than the correlating group for the rate type curve presented in the past. Finally, an analysis method that comprises type curve and derivative type curve matching to determine the dimensionless variables is proposed and demonstrated with a simulated example.
