OFITE, 11302 Steeplecrest Dr., Houston, TX 77065 USA / Tel: 832-320-7300 / Fax: 713-880-9886 / www.ote.com 2
The Permeability Plugging Tester (PPT) is a modication of the standard 500-
mL HTHP Filter press. It may be used in the eld or in a laboratory environ-
ment. The instrument is useful for performing ltration tests on plugging ma-
terials without the interference of particles settling on the lter medium during
the heat up process. The PPT is very useful in predicting how a drilling uid
can form a low permeable lter cake to seal off depleted, under pressured
intervals and help prevent differential sticking. Typical differential pressures
are much higher than those seen in standard HTHP testing
The pressure cell is similar to those seen in standard HTHP ltration testing,
but it is inverted with the lter medium and the back pressure receiver on top
of the assembly. The conventional cell may be operated to 2,000 PSI by us-
ing hardened steel set screws to secure the cell cap. For elevated pressure,
OFITE has designed a special cell with a working pressure of up to 4,000
PSI, pressurized with the conventional hydraulic pump. The cell is pressur-
ized with hydraulic oil and a oating piston separates the oil from the test uid
within the cell.
The cell is furnished with a threaded cell inlet cap, a oating piston, and a
threaded scribed outlet cap for the ceramic lter disks. The outlet end of the
cell has a ¼" (6.35 mm) deeper recess than a standard cell to allow for the
ceramic disk as a lter medium. The end cap used with the ¼" (6.35 mm)
disk has a scribed concentric pattern rather than the conventional screen.
Filter paper or other thin lter medium may be used with this cap by using
the spacer ring (#170-72) to ll the extra ¼" (6.35 mm) space. Also, an extra
thick end cap with a standard screen backup is furnished to use with thin lter
media - paper or metal.
All of the end caps are designed to accept the standard valve stem. The
inlet, or bottom, valve stem is tted with a quick-connect for the connection
to the hydraulic pressure manifold. The standard hydraulic pressure mani-
folds are equipped with a 4,000 PSI (27,600 kPa) relief valve. The outlet, or
upper, valve stem assembly consists of a dual valve stem with a ball valve in
the middle, which facilitates the opening and closing of the outlet ow. Power
consumption for the PPT heating jacket is 800 watts.
The 100-mL back pressure receiver is mounted on top of the heating jacket
and upside down, when compared to the normal HTHP lter press congura-
tion. It attaches to the cell outlet valve stem and is secured with the safety
pin (#171-23-1). The ttings on the receiver are reversed with the pressure
inlet on the small end (the upper end). A are tting may be provided if it is
desired to use the low-pressure side of a dual manifold on a nitrogen bottle
instead of the standard CO2 cartridges.
Intro
Description
