Proppants are used in the hydraulic fracturing process to increase the flow of hydrocarbons to the wellbore and laterals thousands of feet below ground. The technology and science of proppant pack and fracture performance, both initially and over time, continues to develop. And each unconventional formation is different. Each downhole set of conditions is different.
Most important in the selection process for a proppant for a specific well is setting forth a minimum conductivity threshold taking into account all propped fracture conductivity damage factors that may be apparent, e.g., non-Darcy flow, multiphase flow, gel residue damage, embedment, etc. Evaluation of the “right” proppant also involves examination of reservoir specific testing and analysis which may include crush profiles, point specific conductivity measurements, cyclic loading, proppant flow-back analysis, etc. (SPE 116054)
The new testing procedures for comparison of conductivity data are incorporated in two ISO testing standards. ISO 13503-5 “Procedures for Measuring the Long-Term Conductivity of Proppants” replaces APR RP 61. The revised procedures for API RP 56, 58, and 60 are described in ISO 13503-2 “Measurement of Properties of Proppants Used in Hydraulic Fracturing and Gravel-Packing Operations”. Importantly, per SPE 110697, these two new procedures allow for evaluation and comparison under described laboratory test conditions. “They are not designed to provide absolute values of proppant conductivity under downhole reservoir conditions. Test data has shown that time, elevated temperatures, fracturing fluid residues, cyclic stress loading, embedment, formation fines, and other factors will further reduce proppant pack conductivity.” (SPE 110697)
Chieftain’s technical resources and strategic partners can help your Company with its proppant requirements, today and as they evolve in the future.
The following resources may prove helpful:
American Petroleum Institute – www.api.org
Independent Proppant Testing Labs
Proptester – www.proptester.com
Stim-Lab - www.corelab.com/pe/stimlab/default.aspx