Page 36 - Oil and Gas Production Handbook An Introduction to Oil and Gas Production

stuffing box. The sucker rod continues down to the oil level and is connected
to a plunger with a valve.

On each
upward stroke,
the plunger lifts
a volume of oil
up and through
the wellhead
discharge. On
the downward
stroke it sinks (it
should sink,
and not be
pushed) allowing oil to flow though the valve. The motor speed and torque is
controlled for efficiency and minimal wear with a Pump off Controller (PoC).
Use is limited to shallow reservoirs down to a few hundred meters, and flows
up to about 40 liters (10 gal) per stroke.

3.6.2 Downhole pumps

A downhole pump inserts
the whole pumping
mechanism into the well. In
modern installations, an
Electrical Submerged Pump
(ESP) is inserted into the
well. Here the whole
assembly consisting of a
long narrow motor and a
multi phase pump, such as a
PCP (progressive cavity
pump) or centrifugal pump,
hangs by an electrical cable
with tension members down
the tubing. Ill: Wikipedia.org

Installations down to 3.7 km with power up to 750 kW have been installed. At
these depths and power ratings, medium voltage drives (up to 5kV) must be
used.

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