The global refining industry faces the challenges of upgrading its capacity to produce less-polluting fuels while processing increased volumes of poorer-quality crudes, Standard & Poor’s said in a recent special report on fluctuating oil prices.More heavy and sour crude is coming onto the market, and the complex process of refining this crude into fuels that meet stricter low-sulfur regulations is costly, S&P analysts said.A growing price differential between light and heavy crudes will make it harder for refiners as they process greater volumes of lower-quality crude. Consequently, refiners must find the capital to fund enormous construction demands, S&P analysts said.O...