BRIEF-Exxon Mobil CEO says oil markets 'more balanced,' but still sees uncertainty

Chief Executive Darren Woods says continues to expect volatility in oil markets for near term

* CEO says oil markets have become 'more balanced,' but adds 'uncertainty remains'

* CEO: 'We remain in excellent financial condition'

* CEO says annual capex of $25 billion likely by end of decade

* CEO says startup of Liza phase 1 project still forecast for 2020

* CEO says 'very excited about future potential' in offshore Guyana

* CEO says considering adding trains to Papua New Guinea liquefied natural gas project

* CEO says 2020 capex outlook does not factor in significant cost inflation

* Says production outlook factors in 3 percent base decline rate

* Says Argentina shale 'as good as' shale reserves in contiguous United States

* Says continues to try to cut well costs in Argentina, which are roughly 2-3 times higher than United States

* Says looking for shale projects outside Western Hemisphere, including Middle East