Pressure Transient Tests
In addition to isolated tank testing of production wells, pressure transient tests were performed at injection wells to provide a quantitative measure of reservoir transmissibility and wellbore skin before and after polymer treatments. Pressure falloff tests were performed with pressure gauges at perforation depth and test durations from 72 to 148 hrs. Table 4 is provided as quantitative reference for how permeability or injectivity at the injection wells has been affected by the polymer-gel treatments. There were two post-treatment falloff tests. These tests indicate that the permeability-thickness (kh) was reduced from 126 md-ft to 37 md-ft at the SU 3-21 well. The SU 10-28 well indicates a reduction from 43 md-ft to 24 md-ft. Wellbore skin (S) did not change significantly before and after treatment. The SU 10-28 well had a skin of -4.3 before and - 4.1 after while the SU 3-21 had a pre-treatment S of -4.7 and a post-treatment S of -3.7. Transmissibility and wellbore skin were computed using the Miller-Dyes-Hutchinson semi-log method. This is not the result which was anticipated as it was expected that kh would remain the same and skin would increase. No explanation can be offered for this result.
