Mukesh Ambani’s Reliance Industries (RIL), has agreed to pay Pioneer Natural Resources Co. and its partner Newpek LLC a sum amounting to $1.3 billion (Rs.5,850 crore) for a 45 percent stake in its Eagle Ford shale formation.In the Joint Venture (JV) Company, RIL will hold 45 percent stake with Pioneer at 46 percent and Newpek at 9 percent.