Oil & Natural Gas Corporation (ONGC) today reported a 11% increase in net profit at Rs 3,887.76 crore for the third quarter ended December 31, 2005 when compared with Rs 3,493.32 crore in Q3FY05.According to a release issued by the company to the BSE today, total income increased to Rs 13,038.01 crore in Q3FY06 from Rs 12,565.13 crore in Q3FY05.