Oxidative Kerogen Degradation: A Potential Approach to Hydraulic Fracturing in Unconventionals

摘要

Oil and gas production from shale formations has proven to be economical because of advances in hydraulic fracturing but remains very challenging in part because of the presence of the ductile, polymer nature of the hydrocarbon source material, kerogen. This organic matter is intertwined among silicates, aluminosilicates, and other minerals as fine laminae that weave among the shale rock fabric, adding soft mechanical cohesion to the material. A potential solution has been developed, a new type of reactive fracturing fluid composed of strong oxidizers such as bromate (BrO3-), which could mitigate the adverse effects of the polymeric nature of kerogen on the hydraulic conductivity of the fractured shale formation. High-resolution scanning electron microscopy of kerogen-rich shale samples before and after fluid treatment demonstrates notable porosity enhancement evident by cracks forming in the macerals and augmenting the volumetric porosity. The stability of the reactive components at elevated reservoir temperatures in addition to the demonstrated results suggest the potential for measureable improvements in hydraulic conductivity and hence in the ultimate recovery of oil and gas from future hydraulic fracturing operations.