Oil prices slip as reviving shale balances OPEC cuts

By Christopher Johnson LONDON (Reuters) - Oil prices slipped on Tuesday as lower production by OPEC and other exporters was undermined by growing evidence of a revival in U.S. shale production and sluggish demand. Benchmark Brent crude was down 30 cents at $55.42 a barrel by 1330 GMT. On Monday, the Brent futures contract closed down $1.09 a barrel.