DEVELOPING A MOLECULAR-LEVEL UNDERSTANDING OF THE EFFECT OF OXIDATIVE BREAKERS IN SHALE-FRACTURING FLUID INTERACTIONS: IMPLICATIONS ON HYDROCARBON RECOVERY AND CRITICAL METAL (CM) RELEASE
The goal of this study was to develop a molecular-level understanding of the fluid-rock interactions between Marcellus Shale OM and oxidizing HF fluid (HFF) at the formation temperature. Three synthetic HFF solutions containing oxidative breakers, sodium hypochlorite, sodium bromate, and ammonium persulfate, were reacted with shale OM for a 14-day period to mimic the shut-in period. The molecular structural parameters of shale OM (i.e., kerogen) were characterized before and after the reaction using 13C solid-state NMR analysis. In addition, the reacted fluids were characterized using ICP-MS analysis to determine the amount of CMs released. Our preliminary results indicate sodium hypochlorite, sodium bromate based HFF can significantly degrade kerogen by 46% and 60%, respectively. Interestingly, it was determined that oxidative breakers mainly degrade the protonated aromatic fraction of the kerogen and release several CMs such as V, Co, Mg, Mn, Al, Ti, and Cu. Our results demonstrate the oxidative breakers could play a key role in improving the recovery of HCs and designing strategies for CM extraction from HF operation.