Moisture-Resistant Sealing Materials for Downhole HPHT Electrical Feedthrough Package

Abstract

A bismuth oxide–based multicomponent glass system, xH3BO3-yBi2O3-(1-x-y-δ)MO-δ· rare earth oxides (REOs) with MO = TiO2, BaO, ZnO, Fe2O3, etc., and lanthanum series–based REOs, for making downhole high-pressure and high-temperature electrical feedthrough package has been developed using high-temperature melt-quenching and sintering technologies. By properly controlling phase structures in material-manufacturing processes, the obtained sealing materials have shown moisture-resistant properties in their monoclinic and tetragonal mixed phase structures but strongly hydrophobic properties in their covalent bond tetragonal phase. Sealed electrical feedthrough packages have been evaluated under boiling water immersion and 200°C/30,000 PSI water-fluid–simulated downhole harsh environments. The post electrical insulation measurement has demonstrated to be greater than 1.0 × 1014 Ω electrical resistance. This article will show that such a high–bonding strength and high–insulation strength sealing material could be used to seal electrical feed-throughs and connectors for 300°C/30,000 PSI downhole and subsea wireline, logging while drilling, and measurement while drilling tools' signal, data, and electrical power transmissions.