The testing of proppants to determine conductivity and permeability at closure stress is an important aspect of the design and evaluation of hydraulic fractures. The data obtained from these tests are important for proppant suppliers and manufacturers in evaluating their sources of supply or in adjusting or modifying manufacturing processes. For the operator it is a basis for comparing performance, quality and value. An understanding of how this data is obtained and its limitations is important in its use and application. The knowledge gained in the industries' understanding of the behavior of proppants has led to modifications and improvements to the conductivity testing apparatus and in test procedures.

Critical components of the equipment and test procedures, including loading of the cell, flow rates and cell design, will affect the test results to a greater or lesser degree. Thus it is important to clearly take into account the various components of the cell and how they may influence conductivity measurements. Further, the standard conductivity apparatus can be used to evaluate various proppant damage mechanisms such as gel damage, embedment, spalling, and stress cycling. At the same time an understanding of the limitations of the data must be appreciated to avoid misuse and misapplication. And while improvements have been made to the acquisition of this data, there remain some barriers to test repeatability that are inherent to the materials being evaluated.

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