Evaluating the Performance of Bio-Polymers for High Temperature Proppant Suspension

Abstract Gravel Pack fluids are usually formulated to match the Well conditions and achieve the job objectives. Rheology, proppant suspension and transportation to the desired interval in the Well, predictable polymer degradation rate, and minimal formation damage are key fluid properties that determine the choice of polymer for the success of gravel pack operation. Various commercial polymers are currently available or in use to blend polymeric fluids. Hydroxyethyl cellulose (HEC) and Xanthan gums are one of the most popular gelling agents and are often readily available. Fluids formulated with Biopolymers such as Xanthan gums have shown some superior performance over Cellulose-based fluids such as HEC. In this study, Xanthan gum-based fluid and another biopolymer termed "Bio-2" were subjected to stringent conditions, based on a job design request. The Well temperature is between 190 °F to 210 °F and it was requested that the polymeric fluid should be able to suspend at least 10% of the proppant for 30 minutes after conditioning at the downhole conditions. The test result showed that 70 lb/1000gal (ppt) and 80 ppt of the Xanthan fluid showed good rheological properties with shear-thinning behavior and good gel degradation properties with sodium persulfate (SP) breaker, but 70ppt Xanthan fluid failed the proppant suspension test, while 80ppt Xanthan fluid passed the test at 190 and 200°F but failed at 210°F. Bio-2 also showed good rheological properties with a lower concentration of polymer of 40 ppt and excellent proppant suspension of 0% at 30 minutes at all the tested temperatures. Moreover, an organic acid was observed to be the most effective gel breaker for Bio-2 at low concentrations. Therefore, Bio-2 may be deployed in Wells with more challenging requirements, such as in highly deviated or long horizontal Wells, shunt packings, and other stringent conditions that require excellent proppant suspension and thermal stability.