Erosion by Sand and Ceramic Proppants During Slurry Injection and Proppant Flowback

Abstract

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 90604, "Erosion by Proppant: A Comparison of the Erosivity of Sand and Ceramic Proppants During Slurry Injection and Flowback of Proppant," by M.C. Vincent, SPE, Carbo Ceramics Inc.; H.B. Miller, U. of Arizona; D. Milton-Tayler, SPE, FracTech Ltd.; and P.B. Kaufman, SPE, Carbo Ceramics Inc., prepared for the 2004 SPE Annual Technical Conference and Exhibition, Houston, 26-29 September. During fracture-stimulation treatments, particle-laden slurries may damage pumping equipment and have been shown to erode perforation tunnels. During subsequent flowback operations, minor to severe erosion of surface equipment may be observed if formation sand and/or proppants are produced. This paper compares the erosivity of sand-based and ceramic proppants. The erosion mechanisms are examined, and theoretical and laboratory measurements are in agreement that low-density ceramic proppants, because of roundness and sphericity, are less erosive than more-angular sand products. Introduction Impingement tests designed to simulate flowback conditions demonstrated that use of a spherical lightweight ceramic (LWC) may reduce wellhead or other impingement-surface erosion by up to 95% compared with an angular sand. Additional studies with intentionally crushed proppant (to increase angularity) demonstrate that proppant shape is a dominant factor in controlling erosion. Surprisingly, flowback testing has shown that resin coatings applied to proppant can increase erosion 15-fold. Erosivity and abrasiveness of all proppant types were shown to increase with prop-pant damage. Erosion in chokes was found to be three times greater with sand than with LWC. Several laboratory studies have demonstrated that spherical proppants are less likely to flow back from the fracture than more-angular products.