Part No. 171-91 Permeability Plugging Apparatus Model PPT-189

The Permeability Plugging Apparatus (PPA) is a high pressure, high temperature instrument designed to simulate downhole static filtration. The PPA operates at temperatures and pressures that represent well conditions, and the filtration medium is positioned above the sample fluid.

The PPA is very useful in predicting how a drilling fluid can form a low permeable filter 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 permeability plugging test is useful in predicting a drilling fluid’s ability to form a semipermeable filter cake that will seal off depleted under pressure intervals and help prevent differential sticking.

Pressure is applied from the bottom of the cell and filtrate is collected from the top. This arrangement prevents particles that settle during the static test from contributing to the buildup of filter cake. This is important because settling would not normally happen in a well.

Hydraulic pressure is transferred to the drilling fluid sample through a floating piston within the cell. Hydraulic oil and sample contamination is prevented through an O-ring seal on the piston.

The maximum test pressure is 5000 psi (34,473 kPa). And the maximum temperature is 500°F (260°C). The maximum pressure for the backpressure receiver is 750 psi (5171 kPa).

The PPA assembly consists of the following items:

•     PPA Heating Jacket

•     5000 psi (34,473 kPa) psi stainless steel PPA cell

•     Backpressure Receiver

•     Carbon Dioxide Pressurizing Assembly

•     Hydraulic Hand Pump Assembly

•     Dial Thermometer

•     Graduated Cylinder