Flowmeters - Cased-Hole Log Analysis and Reservoir Performance Monitoring - page 63

Continuous Flowmeters
The continuous flowmeter is so named because, unlike the packer flowmeter which
makes station measurements, it makes a continuous log of flow against depth.
Figure 5.3 shows the general form of these tools. Figure 5.4 shows details of the
spinner section. Note that the cross-sectional area “seen” by the spinner is very
small compared to the total area available to wellbore fluids. For this reason, these
tools are less sensitive than the packer flowmeter, but can record much higher flow
rates without danger of being shot out of the hole.
Fig. 5.3 Continuous
flowmeter. Courtesy Titan
Since the continuous flowmeter log is recorded with the tool in motion, the fluid
velocity active on the spinner is the algebraic sum of the cable speed and the fluid
speed. The normal mode of operation is to move the tool against the flow. An
important part of the measurement is thus the cable speed itself and this is usually
recorded in Track 1 of the log. Figure 5.5 shows a typical continuous flowmeter
recording.