Oil companies that have pumped trillions of barrels of crude from the ground are now saying the future is in their other main product: natural gas, a fuel they're promoting as the logical successor to coal. With almost 200 nations set to hammer out a binding pact on carbon emissions in December, fossil-fuel companies led by Royal Dutch Shell PLC and Total SA say they're refocusing on gas as a cleaner alternative to the cheap coal that now dominates electricity generation worldwide.