In the build up to D Day there was also a requirement to bomb targets away from Normandy more than Normandy itself which means targets were bombed for psychological not military reasons. It is very difficult to destroy a refinery, you can damage it and it can be repaired. It should not be forgotten how much the Russian advance removed oil capacity from the Nazis or how much it concentrated the remaining targets to be hit.The Oil Plan officially started after the invasion.
The Transport Plan was in place in the lead up to the invasion.
The two plans were put forward by the British and the 8th AF. The British (Portal?) pushed the Transport Plan and the the 8th AF the Oil Plan (Spaatz). The Transport Plan was chosen, but Spaatz was given permission to bomb oil facilities when the transport targets could not due to weather.
The Transport Plan was aimed at restricting movement of men and materials in occupied Europe, particularly in and around the invasion area. There may have been some effect on oil production because transport of coal to the synthetic oil plants was restricted.