Canadian-owned Talisman Energy (TLM.NYSE, TLM.TSE) will explore for oil off the Vietnamese coast despite China’s rival claims to the area, The Wall Street Journal reported. International oil companies in the South China Sea have increasingly become involved in territorial disputes. Exxon Mobil (XOM.NYSE, XONA.FRA) drilled wells in contested territory in 2011 and 2012, saying sovereignty disputes are for governments to resolve. Chevron (CVX.NYSE), on the other hand, canceled exploration plans east of Vietnam in 2007 after China said its actions violated Chinese sovereignty. Tensions have been high since China sailed a rig into waters claimed by Vietnam in May, which it removed Tuesday.