Selection and Testing of Proppants for EGS

Abstract

In this paper, we present the results of investigating proppant pack performance when subjected to high temperatures (up to 320 °C) in the presence of water for one to two weeks. Crush resistance and proppant packing strength in dry and heated conditions were studied to understand the proppant performance in high temperature EGS environments. AE response was utilized to estimate the approximate packing strength and fines percentage was used to evaluate the crush resistance. In addition, surface features and fracture mechanisms were studied under magnification using SEM. Fluid heated with proppant was collected to observe proppant dissolution or chemical alteration. The results show that the heated proppant in EGS conditions has a lower approximate packing strength and yields a higher fines percentage, indicating reduced conductivity after its exposure to high temperature fluid for 14 days. The capability of polymer coating, encapsulating and trapping fines within polymer coating, is reduced by coating degradation in high temperatures fluid, resulting in significant increase in fines percentage compared to non-coated proppants.