Patent ID: 9027646
Filing Date: 2015-05-12
Classification: C09K

Abstract:
1. A method of reusing a produced fluid in a hydraulic fracturing operation, the method comprising: receiving the produced fluid from a well as a return of at least a hydraulic fracturing fluid in a hydraulic fracturing operation; providing a production brine recovered from an oil or gas extraction operation, the production brine having a conductivity of at least 150,000 μmhos/cm; measuring a conductivity of the produced fluid; treating the produced fluid by adding thereto at least the production brine to form a treated produced fluid, wherein the treating of the produced fluid comprises: increasing the conductivity of the produced fluid to at least 100,000 μmhos/cm; increasing an iron content of the produced fluid to at least 50 ppm; and adjusting the pH level of the produced fluid to between 5.0 and 6.5; and thereafter increasing an oxidation-reduction potential value of the produced fluid to at least 250 mV, thereby forming Fenton's reagent in situ within the treated produced fluid; storing the treated produced fluid for a sufficient time to allow flocculation of suspended solids in the treated produced fluid, thereby forming a clarified produced fluid from which the suspended solids have been removed; and injecting the clarified produced fluid into a well as part of a hydraulic fracturing fluid; wherein reaction of the Fenton's reagent causes formation of complexes of iron and the suspended solids; and wherein the formation of the complexes causes coagulation and flocculation of the suspended solids.