[JimboOmega]

But more oil is used to transport the oil (in trucks/trains), so I think that increases CO2 usage overall.

Also higher prices mean more oil is exctracted - and sometimes more is used to do the extraction (IE, more marginal EROEI projects are undertaken)

[Symmetry]

It's higher profit for extracting that would mean that more oil would be extracted, not higher prices to the consumer. Higher transport prices decrease ROI.

You have a point about transport CO2 use but I'd expect that would use a small amount proportionally.