Most oilfield workweeks range from 60 to 84 hour weeks (some even more hours).
For Drilling Consultants, they are on location 24/7 for their 'hitch', for some rigs there are two working 12 hours on, 12 hours off (84 hrs/wk), on other rigs, they are on call 24 hrs and work shifts of up to 14 days on/off (a few work the whole well, straight through).
The Alaskan North Slope operating and maintenance positions are similar to O&M in the offshore or other remote land positions. But most every job like this has nothing to do but eat and sleep (and possibly drink). The rec-rooms have gotten nicer over the decades but still rather limited by general public standards. They work 7/12s but are off half the time; 2/3/4/5 weeks on then the same time off. Greater times for start-up or turn-arounds.
It is not for everyone, but it can be rewarding. What I have found at nearly all these place was consistently good food. That was a bit of a stretch living in Yemen; first and last time I ate spam as a pizza topping.