The state-owned company has approved capital investment of $743 million in the project.
ONGC plans to install five well platforms and modify 13 platforms. The project also includes one clamp-on facility for wells at an existing platform and associated pipelines.
Facilities are to be installed by April 2016. The project is to be complete by May 2017.
ONGC expects the new phase to boost field recovery by 51 million bbl of crude oil and 186 bcf of natural gas by 2030.