In-Depth Laboratory Proppant Transport Study Using HVFRs for Marcellus High TDS Environments

Abstract

Summary Excellent proppant transport can be accomplished by introducing high-viscosity friction reducer (HVFR) fracture fluids. However, HVFRs face several challenges that prevent these fluids from providing good proppant transport performance, including the presence of total dissolved solids (TDS) in the produced water. TDS can negatively impact the viscous and elastic properties of HVFR. This study evaluated the rheological and proppant transport performance using HVFRs at extreme salinity conditions using water samples from the Marcellus Basin. The anionic and cationic HVFRs with a concentration of 4 gpt were used. Experimental evaluation work, including the rheology, static proppant settling measurements, and dynamic proppant transport, was conducted using three Marcellus TDS concentrations (68,000; 137,000; and 229,000 ppm). All the experiments were performed at a high-temperature condition that mimics the Marcellus reservoir temperature of 65.5°C (150°F). The results show that the existence of TDS was largely impacted by both types of HVFRs, but the cationic HVFR exhibited better resistance to the Marcellus TDS compared to the anionic HVFR in terms of transporting proppant. The viscosity of the anionic HVFR was reduced more than that of the cationic HVFR, as TDS concentrations increased to 229,000 ppm. However, the elasticity of both HVFRs was weak, as a switch was made from using low TDS to high TDS. This could imply that HVFR viscosity provides the main contribution to proppant transport in high TDS environments. Therefore, it is crucial to evaluate the impact of TDS on the effectiveness of HVFR by investigating HVFR rheology, static proppant settling, and dynamic proppant transport in the TDS environment.