Generic Correlations for Proppant-Pack Conductivity

With the large number of fracture stages and the size of jobs being pumped in horizontal wells, many companies have elected to use nonstandard or noncommercial natural sands as propping agents. The Stim-Laboratory Proppant Conductivity Consortium, supported by approximately 50 proppant suppliers, pumping service companies, and operators, has developed consistent laboratoryconductivity-test procedures during the past 30 years that have become de facto industry standards. One outcome of this long history of proppant testing is a set of correlations that can predict the baseline conductivity, as a function of closure stress and rock (substrate) properties, within the range of uncertainty of laboratory tests. Inputs to the correlations are basic material-property measurements such as specific gravity (SG) and median particle size of the sieve distribution. The correlations can be used to compare materials of unknown properties with standardized data sets, or to develop useful predictions of how a non-American Petroleum Institute (API) standard material is likely to perform. The correlations are general enough for application to brown sand, white sand, resin-coated materials, and ceramic proppants of various sizes and densities. These correlations have been found to be sufficient for comparing proppants and for estimating their performance in production computations, when adjustments for appropriate damage and cleanup are made to the calculated-baseline-conductivity values.