API RP 13C: An Explanation and Answers to Frequently Asked Questions-chapter 1

Brightway manufactures a full inventory of shale shaker screen that combine fluid capacity with long life.

Our screens are manufactured in a board range of mesh sizes to ensure maximum solids control efficiency regardless of the formations drilled.

In shale shaker screen production, we follow the standard of API RP 13C.

As a professional manufacture, we pay great attention on the API standard.
Let's learn the API RP 13C

API RP 13C:  An Explanation and Answers to   

Frequently Asked Questions  

This document is available for distribution throughout the Industry.

Summary
API has revised the shale shaker screen testing procedures and numbering convention. By using the   new API Screen Number, confusion among screen types is reduced and comparison between screen   types can be made fairer. Some screens which may previously have been named “200 mesh” may   now have an API Screen Number of only 100 to 140. However, ALL screens which are tested   according to RP 13C and have the same API Screen Number will remove solids of a similar size.

Note: The change from using D50 to D100 (50% of a specific particle size removed versus 100%) will   change the rating of most screens  – the extent of the change being dependent upon screen   type/design.

The new number describes the size at which particles will be rejected (removed) under laboratory   test conditions. The new API number is NOT intended to describe how the screen (or indeed the   shaker) will operate in the field. This will depend upon several other parameters such as fluid type   and properties, shaker design, operating parameters, ROP, bit type, etc.

The greatest value of the new numbering system is that ALL conforming screens are measured using   the same process which will allow cross-comparison of screen designs/types based on a uniform   solids size removal value.

Any manufacturer labeling their screens as “conforming to API RP 13C” must supply the test data   for that screen upon request to the end user/purchaser.

Definitions

Mesh:  Mesh, as it relates to a piece of woven wirecloth, is a measure of the number   of holes in a linear inch (such as 100 mesh) or in a linear inch in each direction (such   as 100 x 60 mesh).

D50 Cut Point: The D50 cut point of a screen is the particle size at which half of those   particles reporting to the screen will pass through the screen and half will be   retained.

D100 Cut Point: The D100 cut point of a screen is the largest particle size which will   pass through the screen.

API Screen Number:   The API Screen Number is determined using a specific test   procedure (as described in API RP 13C). The test uses a specifically graded sample of   aluminum oxide, which passes through the unknown screen mounted amongst a   stack of ASTM test sieves.  The test method determines the D100 cut point of the test   screen and relates it to the D100 of an ‘equivalent’ standard ASTM test sieve.

Screen Conductance:
Conductance, measured in kilodarcies per millimeter   (kD/mm), defines a Newtonian fluid’s ability to flow through a unit area of screen in   a laminar flow regime under prescribed test conditions. All other factors being equal   the screen with the higher conductance number should process more flow.

Non-Blanked Area:  The non-blanked area of a screen describes the net unblocked   area in square feet (ft²) or square meters (m²) available to permit the passage of   fluid.

***To be continued***