(57) A downhole tool apparatus has a housing (12) with a compression chamber (232) defined
therein. A fill passage (234) is disposed through the housing for placing the compression
chamber in open flow fluid communication with a well annulus (236) so that well fluid
may flow into the compression chamber as the apparatus is lowered into a well. An
isolation valve (242) selectively closes the fill passage to trap well fluid in the
compression chamber. An operating element (162) is operated by an actuating piston
(140) slidably disposed in the housing. A first side of the actuating piston is in
fluid pressure communication with the compression chamber so that a volume of the
compression chamber is decreased when the actuating piston moves between first and
second position thereof relative to the housing. An injection passage (286) is preferably
provided for injecting pressurized gas into the compression chamber at a location
within the compression chamber such that the injected gas will directly contact at
a gas-well fluid interface an upper surface of well fluid that flows into the compression
chamber. The compression chamber is preferably primarily defined by an elongate diametrically
irregular annular space, and the gas-well fluid interface moves upward past a number
of irregular diameters of this diametrically irregular elongated space, as the apparatus
is lowered into a well.
|
|
