Antenna operation for reservoir heating

Systems and methods are provided for maintaining the performance and operational stability of an RF (radio frequency) antenna that is positioned in a hydrocarbon-bearing formation, for heating the formation using electromagnetic energy in the radio frequency range. Contaminants such as water or brine, metallic particulates and ionic or organic materials frequently occur in a wellbore being prepared for RF heating, or in an RF antenna installed in the wellbore. Prior to applying RF electrical energy to the formation, the antenna is decontaminated by circulating a preconditioning fluid through the antenna and recovering a spent fluid for treating and recycle. Decontamination is continued while the spent fluid from the antenna includes, but not limited to, water, metallic particles, ionic species, organic compounds contaminants, etc. An operational power level of radio frequency electrical energy is then applied to the decontaminated antenna for providing thermal energy to the hydrocarbon-bearing formation.