Oil demand will soon outpace oil supply, warned Matthew Simmons in a July 1 talk to the American Association of Professional Landmen, an oil and gas trade group. Simmons, an outspoken voice warning of looming energy challenges, is also chairman of Simmons & Co., an energy-focused investment bank in Houston. “Demand has become a runaway train,” he warned, echoing a message in his recently published book Twilight in the Desert: The Coming Saudi Oil Shock and the World Economy.