My sister has been a petroleum Geologist on the production side since 1980. Virtually all she worked on was the existing California oil fields and she had plenty of work. She's mostly retired now because everybody pretty much stopped drilling new wells in the US in the 2018-2019 time frame. The shale oil had become a glut on the market and anybody with leases on low volume wells was losing their shirt with the low oil prices.
Drilling new wells in existing fields is quicker than bringing an entirely new field online, but each new well takes a few months of Geology work to site the well properly and anticipate at what depth the oil will be found. The landscape under the Earth can vary just as much as the surface.
Once the Geology is done, all the services to drill and finish the well need to be booked. That's tougher now because when the price of oil cratered, a lot of people retired, went and did something else, or moved abroad to drill wells overseas. The well drilling equipment near the end of life was scrapped, the newer stuff went overseas, and nobody has made any new equipment in ~5 years. Again, a lot of the expertise is off doing something else.
The average age of the technical skills in the oil business is quite high because the major oil companies quit training new talent in the early 1990s. It used to be that the major oil companies were where everyone started fresh out of school. Some would stay on, while others would branch out to smaller companies that didn't have the money to train new talent. When the majors quit training, the average age of the technical people started getting older and now a high percentage are retirement age or older.
I have a friend who was a career Geophysicist at Marathon Oil. He took early retirement at 55 and worked for a couple of smaller Geology firms for about 10 years. Every place he worked, he was one of the youngest professionals in the office.
The oil business is struggling to ramp up production to replace Russian oil because the talent to do the job just aren't there anymore.