The usual rule within finished spaces is "any point along the wall must be within 6' of a receptacle (presuming the 6' appliance cable is hugging the wall, and does NOT cross thresholds)".
I don't really keep up with modern interior design, but I'm guessing oil tanks are not yet fashionable. So we can assume that the oil tank area is NOT a finished space. My advice would be stay 6' away from it, then.
If you need to slip by it with electrical cable, there's no clear Code on that, but I myself would install metal boxes on each end, and then connect them with EMT metal conduit with liquidtight fittings. That way there's zero chance of the wires taking physical damage, which could be the precursor to a fire, if say the oil tank and wires both took damage.