When Tap preempted Roc's sale to Woodside and on-sold it to some Asian crowd, BHP preemted that sale and sold it to Apache. So they cared enough then as to who their J/V partner was.
I am quite sure BHP would rather have someone like Woodside or Chevron (who have common interests with BHP) than Northern as a joint venturer. With Chevron as a joint venturer there could well be synergies eg processing gas through Gorgon or Wheatstone.
