method of moments to yield mean arrival times for each tracer [Jin et al., 1995; Annable et al.,

1998]. Retardation factors for the MLS pre-PITT ranged from 1.06 to 2.69 and from 1.06 to 1.38

for the post-PITT.


 1MLS 4 Post PITTr --HexOH
 1 MLS 6- Pre PITT --MeOH (868 m bgs)
 (9 07 m bgs) E-HexOH
 07 ---- --- MeOH Exp Ext
 0.1 E-HexOH Exp Ext
 0.1

 0.01 U
 0.01
 0.001


 0.0001 0.001
 0 1 2 3 4 5 0 1 2 3 4
 Time (days) Time (days)



Figure 2-3. Examples of breakthrough curves of tracers during the PITTs at Sages. The tail
 region of all BTCs were exponentially extrapolated from linear tail segments,
 including several incomplete tails such as Pre-PITT MLS-6, 9.07 m bgs BTC on
 the left. The right figure is post-PITT MLS-4, 8.68 m bgs.

 The BTCs for wells 2, 3, 4, and 6 were resolved but MLS wells 5 and 7 did not receive

enough tracers during the test to determine SN in those swept regions. Figure 2-3 shows

examples of BTCs from the PITTs. The plot on the left is the data from the pre-remedial PITT

of MLS-6 at a depth of 9.01 m bgs. Moment analysis returned a conservative tracer (MeOH)

mean arrival time of 0.77 days and a partitioning tracer mean arrival time of 1.08 days. The

retardation factor was 1.49 and the average PCE saturation in the swept zone was 0.69 %. The

graph on the right was the post-remedial PITT results of MLS-4 at a depth of 8.68m bgs. PCE

saturations were calculated using Eq. 1-9, and the results are presented in Table 2-2.

2.4 Pre-remedial PITT

 In the RW analysis of Sages for the pre-flood PITT, there were consistently lower

average PCE saturations in the swept zones arriving at RW-3, RW-5, and RW-7 than their