Oil companies. Keep pumping and don’t sell until it is profitable to do so. As far as volume. As much as they can store. How much that is I have no idea.
Not feasible. Company “A” takes his oil off the market so Company “B” makes more money selling oil in a market with smaller supply.
Later, when prices are higher, Company “A” sells extra oil onto the market, driving prices lower.
Expand this past two companies to the entire industry.
and now you know why Saudi Arabia doesn’t want to cut their production so Iran and Venezuela can make more selling oil to a market with less supply. Saudi would be doing as you suggested, “storing” it by leaving some in the ground.