Wasn't this well drilled down to a depth never achieved before? Weren't there technological hurdles to overcome to extract the oil? I'm just curious if anyone has a link or more information about this.

Other wells have been drilled down to the pre-salt layer in the Santos Basin. In this particular area of Carioca none has done so. Information about a particular well where drilling started less than one month ago can't be that much.

There have been deeper wells in the Gulf of Mexico. Take a look at the Jack Project led by Chevron. There were wells approaching 30,000 feet below surface drilled into Oklahoma mainly for gas sometimes oil. I read a rumor of deep wells in the Caspian Azeri area that I could not confirm.

The Tupi project is expected to yield up to one million barrels per day and take about nine years to develop.

This subsalt strata is likely to yield more finds.