Ceramic Filter Disks, 2.5" x .25"
Porous ceramic filters are commonly used for everything from sewage treatment
to medical equipment monitoring. In the oilfield, ceramic filters are used
as a replacement for filter paper in the HTHP filtration test. Available
in a wide range of pore throat sizes, ceramic filters enable the operator
to perform filtration tests at similar porosities to that of the formations
being drilled, a big advantage over filter paper. Also, ceramic filters,
unlike paper, have depth (usually ¼"), so invasion and return permeability
studies may be performed and bridging characteristics of drilling and drill-in
fluids may be analyzed.
Porous ceramics consist of closely-sized particles bonded together, resulting
in a uniform, permeable material that forms a tortuous path for fluid flow.
The most common materials used are alumina and silica, but there is an
almost unlimited variety of material characteristics, shapes, and sizes
Ceramic filters are normally classified by mean pore throat size and/or
units of permeability. Mean pore throat size is the average minimum pore
diameter measured in microns, or a thousandth of a millimeter. Permeability
is a measure of the volume flow of fluids through a porous media when subjected
to a differential pressure and is mathematically equated by Darcy's Law.
Previously, mean pore throat size and permeability were roughly determined
using air standards. Recent research funded by the American Petroleum Institute
(API) used the latest mercury injection capillary pressure technology to
determine these characteristics. This new testing procedure identified
that the ceramic disk manufacturing process does not allow for absolute
consistency between ceramic disk batches. Therefore, it was determined
that the true mean pore throat size and permeability should result as a
mean of the statistical data. Even though the ceramic filters are the same
filters that have been provided for years, new API methods for determining
mean pore throat size and permeability have resulted in new specifications
as outlined in the chart below:
||Mean Pore Throat (µm)
|#170-55||10||3||775 mD||400 mD
|#170-53-2||12||5||850 mD||750 mD
|#170-53-3||20||10||3 D||2 D
|#170-51||40||20||8 D||5 D
|#170-53||50||35||15 D||10 D
|#170-53-1||55||60||20 D||20 D
|#170-53-4||120||90||40 D||100 D
Note: 1 Micron (µm) = 1/25,400" or 1/1,000 mm
HTHP filtration cell bodies must be recessed an extra ¼" on the outlet
side in order to accommodate the ceramic filter. OFI Testing Equipment
can retrofit existing equipment to specifications. A ¼" thick stainless
steel spacer ring is available for those who also wish to use filter paper.
Different sizes and an assortment of other permeable filters are available
on a special order basis.
For more information about this product or to request a quote, contact us.