Unocal’s reserves take center stage

Oil industry pioneer Unocal Corp. was thrust this week into one of the hottest takeover battles in years, when China National Offshore Oil Company Ltd. decided to take on Chevron Corp. for ownership of the 115-year-old company’s assets.

What’s at stake is Unocal’s vast portfolio of proven oil and gas reserves — most of them strategically located a short tanker ride from the factories fueling China’s roaring economy