API RP 19D

This standard provides recommended testing procedures for evaluating proppants used in hydraulic fracturing and gravel-packing operations.

NOTE The proppants mentioned henceforth in this document refer to natural sand, ceramic media, resin-coated proppants, gravel packing media, and other materials used for hydraulic fracturing and gravel-packing operations. 

The objective of the document is to provide consistent methodology for testing procedures used to measure performance of hydraulic-fracturing and/or gravel-packing proppants. The testing procedures in this document are not designed to provide values of proppant conductivity under downhole reservoir conditions. Long-term test data have shown that time, elevated temperatures, fracturing fluid residues, cyclic stress loading, embedment, formation fines and other factors further reduce fracture proppant pack conductivity. Also, this reference test is designed to measure only the frictional energy losses corresponding to laminar flow within a pack. It is recognized that fluid velocity within an actual fracture can be significantly
higher than in these laboratory tests, and can be dominated by inertial effects.