I've been musing this around my head for quite sometime, so forgive me if this seems a little over detailed.
But if you didnt know, the British were actually in control of oil-rich Baku for a short period during their summer campaign into Azerbaijan. The
Dunsterforce, a collection of troops and NCOs under the command of British officer Lionel Dunsterville, were sent to help defend the Armenian Christians located within the city from an incoming attack by a joint Ottoman-Azerbaijani force. While this gambit eventually failed as the Ottomans were able to defeat them and the local Armenian militia, Baku, for at least a few weeks was under nominal British control from late-August to early-September of 1918.
So the central POD is what the opposite occured? What if the Battle of Baku was a decisive victory for the Dunsterforce, the Armenians, and the British in general?
While we can assume that the Brits wouldnt necessarily outright colonize the territory in the aftermath of a successful defense of Baku, but rather would allow it to serve as a staging ground for their general efforts to support the Whites in ongoing Russian civil war, I doubt that the latter's eventual collapse would prevent future incoporation of "British Baku" into the mandate system.
So lets say the this does eventually happen after the Bolsheviks defeat the Whites in 1920. What effects would this British Baku have on the economic vitality of the post-WWI British Empire?
We know that at least by 1901, Baku was generating
11 million tons or 212,000 barrels (33,700 m3) of oil per day. What effect would British control over nearly a third of global oil production by 1920 have on markets and politics worldwide?