High-cost regions from aging North Sea fields to untapped resources in East Siberia and deep-water projects off Latin America will suffer the most from the clash, say Standard Chartered Plc, Citigroup Inc. and BNP Paribas SA. The Organization of Petroleum Exporting Countries refused to cut output in November to eliminate a surplus caused in large part by U.S. production at a three-decade high, leaving more expensive operators to reduce supply.