LONDON, Jan 31 (Reuters) – The structure of the global oil market was increasingly tilted to the downside on Monday, pointing to the likelihood of a reduction in supply of West African crude oil, which remains stuck at peaks last seen in mid-2020.

* The six-month spread between Brent for March delivery versus September delivery was $6.75 on Friday, the steepest since 2013.

* Backwardation market structure is achieved when short-term prices are higher than those of later-dated contracts, resulting in prompt oil prices…