(August 11, 2020, 1:15 PM EDT) -- WASHINGTON, D.C. — Two petitioners on Aug. 7 urged the Patent Trial and Appeal Board to cancel five claims of a patented packer apparatus used in hydraulic fracturing, on grounds that such tools "have been known in the oil and gas industry for more than fifty years" (Exacta Frac Energy Services Inc., et al. v. Paul Bernard Lee, No. IPR2020-01424, PTAB)....