ONGC Petro Additions Ltd (OPAL), in which ONGC owns more than 95% stake, is looking to raise 50 billion rupees ($563.22 million) through a multiple-tranche bond sale, they saidONGC Petro Additions Ltd (OPAL), in which ONGC owns more than 95% stake, is looking to raise 50 billion rupees ($563.22 million) through a multiple-tranche bond sale, they said Latest News [ SOBAN NEWS: International and National ]