The Financial Post reports in its Wednesday edition that Canadian energy firms should prepare for a tough time getting access to credit as they return to their lenders in the months ahead. The Post's Jonathan Ratner writes that low oil prices are expected to force Canadian banks to cut their credit lines for many exploration and production firms by as much as 20 per cent. One reason is because many of the hedges that oil producers have in place are maturing, which means reserves will be assigned lower valuations. There have been no major flare-ups yet, but Canaccord analyst Gabriel Dechaine notes that there was a spike in third quarter oil and gas loan impairments. He says National Bank of Canada has potentially the greatest relative exposure to possible credit quality deterioration in the banking sector. He also highlights Bank of Nova Scotia as another name with higher-than-average exposure to the oil and gas sector. Canaccord says Trican Well Service, Calfrac Well Services and Entrec have the highest degree of leverage. Meanwhile, Total Energy Services, Secure Energy Services, Canyon Services Group, Essential Energy Services and McCoy Global are considered to have the most flexible balance sheets.