Other than Shale, indeed oil exploration is moving deeper into the ocean and more miles beneath the surface. Which does make it costly to explore, recover and ship to consumers onshore and across continents. With big oil investments on hold and not just rigs, regaining the momentum to meet the demand will indeed be time consuming. In oil business they do say its a cycle. We just don't know how soon will the price accelerate back.
Delayed impact of Canada fire on US Stocks (Cushing) up to 20 MMbl over 2 weeks of reports is expected. Apparently the Oil from Oil Sands flows really slow through the pipeline. So while the fire was going on the oil already in pipe didn't have an impact on inventory. Similar situation with oil flowing from impacted Nigeria and Venezuela will show an impact on inventory. for at least 2 weeks - the impacted supply was 3-4 mbpd = 40-50 MMbl. However while Canada and Libya impact has ended and the production will come back in time, it is going to take 1-2 weeks for normalcy. Whereas impact in Nigeria 800 K and Benezuela 200K and other impacts such as rest of LATAM and US shale will continue to the tune of 1.5-2 mbpd - balancing the output to Demand.