Oil prices slumped up to nearly 8 percent to the lowest in more than a year on Friday, posting the seventh consecutive weekly loss, amid intensifying fears of a supply glut even as major producers consider cutting output. Oil supply, led by U.S. producers, is growing faster than demand and to prevent a build-up of unused fuel such as the one that emerged in 2015, the Organization of the Petroleum Exporting Countries is expected to start trimming output after a meeting on Dec. 6. But this has done little so far to prop up prices, which have dropped more than 20 percent so far in November, in a seven-week streak of losses. Prices were on course for their biggest one-month decline since late 2014. A trade war between the world’s two biggest economies and oil consumers, the United States and China, has weighed upon the market. […]