Flowmeters - Cased-Hole Log Analysis and Reservoir Performance Monitoring - page 60

Table 5.1 Flow-measuring devices
Tool Flow rate

Packer/basket Low low (10-1,900 B/D)

Continuous flowmeters High flow (3,000 B/D and up)

Full-bore flowmeters Medium flow (50 B/D and up)

Radioactive tracers Any rate

Oxygen activation (Special limitation)

(Thermometers) (Qualitative only)

Packer and Basket Flowmeters

Packer flowmeters and basket flowmeters both operate in a similar mode. The tool
is lowered through the tubing and then held stationary in the casing. The total flow
is then forced to pass through a central tube containing a spinner. This is achieved
in the case of the packer flowmeters by means of an inflatable packer bag. The bas-
ket flowmeters open overlapping metal “petals.” Figure 5.1 illustrates a packer
flowmeter with its packer bag inflated. Stationary measurements are normally made
in the casing between sets of perforations. The flow into or out of any set of perfora-
tions is deduced from the measured flow above and below that set of perforations.
Raw tool readings are in terms of spinner revolutions per second. Depending on the
diameter and pitch of the spinner used, the measured rate of rotation [revolutions
per second (rps)] is converted into a flow rate in barrels per day. Presentation of the
log may be in the form of a flow profile or by contribution to total flow by zone.
Figure 5.2 illustrates a basket flowmeter survey for a producing well.