Oil is commonly formed in rock or in sealed pockets under the seabed and it is from the Latin for 'rock oil' that the word 'Petroleum' is derived
we get fuel from under its because the ground it self have oil and god the only one who knows
Drilling oil and gas wells and hydraulic fracturing
International Seabed Authority
East Timor
Oil drilling often occurs on the seabed, that is, the very bottom of the ocean.
The tunnel is 50.5 km long (31.4 miles). of which 37.9 km. (23.5 miles) is below the seabed.
Drilling for oil on land is usually cheaper than drilling under the seabed due to several factors. On land, the infrastructure costs are lower, as there is no need for specialized equipment, platforms, or pipelines. Additionally, the depth and pressure of the reservoirs under the seabed can be much higher, requiring more complex and expensive drilling techniques. The harsh marine environment also leads to increased operational and maintenance costs for offshore drilling.
dead sea creatures on the seabed being compressed by debris after millions of years of decay oil may be extracted
shelly seabed
The Gulf of Mexico seabed seeps quite a bit of oil, anyway; the planet will surely have more difficulty recovering from the dispersants.
It is unpredictable, however statistics show that a tsunami as result is incredibly unlikely.