When the American Petroleum Institute established standardized crush testing procedures in 1983 (API RP-56), the committee indicated that the test results should "provide indications of the stress level where proppant crushing is excessive and the maximum stress to which the proppant material should be subjected." However, over time many have forgotten not only how the test is conducted, but also its original intent. As such, many now misapply the results of crush testing as they select proppants for their fracture designs.
This paper will review the top ten myths associated with crush testing and its interpretation, addressing such common questions as:
Do standard test conditions (high proppant concentration and low temperature) provide realistic predictions of proppant performance?
Should proppant be tested wet or dry?
Does the loading procedure affect crush?
What happens if proppant is not uniformly distributed in a fracture?
Do all proppants fail in the same manner?
Are all proppant types equally damaged by 5% crush?
How can the industry misuse the test to report "superior" results?
Readers of this paper will be armed with a better understanding of 1) how crush testing is performed, 2) how crush results can be misapplied and 3) the correct use of crush test results. In addition, the authors will present an alternative methodology for evaluating proppant which incorporates all of the benefits gained from crush testing, but avoids the common pitfalls. Armed with this information readers can improve the design of fracture treatments, thereby achieving increased production rates and superior economic returns.