Korea Gas Corp. has approached long-term suppliers of liquefied natural gas (LNG) to defer up to 10 autumn cargos to winter, showing it is lumbered with excess supply and pulling out of spot markets, industry sources said. High stocks and weak demand prompted state-run Kogas, the world's biggest corporate buyer of LNG, to offload a number of cargos this summer through a combination of time-swap deals and by deferring deliveries from suppliers. Deferrals were first meant to include only summer cargos…