Temperature Logging - Cased-Hole Log Analysis and Reservoir Performance Monitoring - page 117

The method used to make the horizontal scan is shown in Fig. 8.15 . Anchor
springs hold the tool in the casing and a rotation motor is actuated to cause the RDT
sensor to scan round the casing. The resulting log is shown in Fig. 8.16 . Note that
the log is a record of temperature versus degrees of rotation round the casing. This
particular survey with measurements made at 6,400, 6,440, 6,500, and 6,560 ft
shows that gas is channeling from the lower sand (marked “L” on the figure) to the
upper sand (marked “U”). For remedial action, the tool carries a perforating gun that
can shoot squeeze perforations directly into the channel once it is detected.
Fig. 8.15 RDT tool.
Reprinted with permission of
the SPE-AIME from Cooke
(1979)