Cutting supply is going to be difficult. Although a massive Royalist vs Islamist civil war in both Saudi and Iran is theoretically possible. It's hard to see such continuing very long, though. One would think one side or the other would win.
Having India and China start growing sooner could massively up the demand for oil earlier. For that, you'd need to get rid of the Socialists in both places. However a KMT victory in China would probably require a pre-War PoD (like getting rid of Chiang); and to get rid of the Fabian Socialism in India probably means getting rid of Gandhi and Nehru.
Hmmm... WITHOUT getting rid of those three...
People in Britain become terrified at the prospect of German bombing (read Neville Shute's prewar stuff, for instance, as an example of how effective aerial bombardment was going to be). So backup aircraft plants (airframes and engines) are built in India, also some work with ship yards. Thus the Indian airforce has local production, and when it's obvious that the German raids aren't nearly as effective as people were afraid they were going to be, those Indian Hurricanes (or whatever is built there) are used (partly) to equip the Indian Airforce. More planes are available in North Africa, more in Southeast Asia. Indian troops and airforce hold Malaya and prevent the Japanese from taking Thailand and Burma. The Burma road survives - and the US builds up the Burman-Yunan rail line. These mean massively more supplies reach Chiang - enough more that he actually uses some against the Japanese. [Unfair, I know, still.] MacArthur is sent to China, and Stillwell to Australia. Chinese units loyal to Chiang are provided with lots of equipment and training, and he ends up the war in complete charge.
Indian pride in their war fighting and industrial prowess counters the pacifism of Gandhi and somewhat discredits his whole 'simple, self-sufficiency' philosophy.
Instead, India looks to build her own industry and exports, like OTL South Korea and Japan did. Instead of wearing homespun, Indian leaders wear locally produced machine spun/woven cotton (there's still the boycott of Lancashire cotton products).
Chiang, seeing the rising economic and military power to his south, realizes HE has to introduce reforms. China starts developing - far more slowly than India or e.g. Japan, but opening slowly (if not, so much, to foreigners, at least to local entrepreneurs).
By 1960, oil consumption in India and China, together, matches that of the US (still a tiny fraction per capita, of course), and the economies are still growing.
Prices of oil start rising, slowly, as the world demand rises.
By 1970, every Indian family has at least a motorcycle, many have a car, and the same is true in Chinese cities. Even in the Chinese countryside, every village has a truck or two.
