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Porous ceramic filters have many applications, but in the oil field they are
used as a replacement for filter paper in the HTHP Filter Press. Available in
a range of pore throat sizes and permeabilities, ceramic filters enable the
operator to perform filtration tests under conditions similar to the formations
being drilled. This is a big advantage over the standard paper filters. Also ce
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ramic filters, unlike paper, have depth (usually ¼") so core analysis, invasion
and return permeability studies may all be performed. Bridging characteristics
of drilling and drill-in fluids may be analyzed.
Porous ceramics consists of closely-sized particles bonded together which
result in a uniform permeable material that forms a tortuous path for fluid
flow. The most common materials are Alumina and Silica, but there is an
almost unlimited variety of materials and shapes available. HTHP filtration
cell bodies must be recessed and extra ½" on the outlet side of the cell body
in order to accommodate the ceramic disk. A ¼" spacer is provided for usage
of filter paper if desired. Different sized ceramic disks to simulate cores and
an assortment of other pore throat porosities/permeabilities are available on a
special order bases.
These ceramic filters are classified by mean pore throat sizes and/or units
of permeability. Mean pore throat is the average minimum pore diameter
through the disk and it is measured in microns, or thousandths of a millimeter.
Permeability is measure of the volume flow of fluids through a porous or semi
porous media when subjected to a differential pressure. It is mathematically
equated by Darcy’s Permeability Law.
Ceramic Disk Filters
