By Joe Leahy in Mumbai

In its press release announcing it will invest up to $1.36bn in a partnership with Pioneer Natural Resources of the US, Reliance Industries mentions that its annual revenue is $44.6bn.

The point immediately raises the question of why India’s largest private energy group is spending so much management time on buying up stakes in non-conventional shale gas deposits, such as Pioneer’s Eagle Ford field in Texas.

Why is Reliance not going for the jugular and picking up bigger, more conventional assets?