You’d have to go out in the Gulf and sometimes tie up to a platform and wait until further instructions came in. Many of the platforms were (and are) caps on existing wells. They have no crew. The captain backs the boat in close to one of the legs that has ladder rungs welded onto it. The legs are big, about 3 or 4 feet in diameter, and covered with giant barnacles, oysters, and very slippery seaweed. If the swell knocks you into the leg you’re going to be bleeding.
Once the boat is close, if you’re the deckhand you take a fat rope that is attached on one end to a giant cleat on the back of the boat, then loop the free end around your shoulder. You dive into the water, swim to the leg, and then wait for the right moment of ocean swell to try and grab the ladder. Lunging at just the right moment, you grab a ladder rung and climb up quick before the next swell comes and knocks you off again. The captain has to keep the boat close but not let the rope get sucked into the screws (yanking you into the whirling propellers). He tries to avoid letting the boat crash into the rig. He tries to keep the boat from crushing you while you are climbing up to tie the rope onto the platform railing. Usually that’s about 10 to 15 feet up. You tie a knot (say a double half hitch) around a railing and then wave at the captain, who backs up the boat until it’s basically right under the platform. Then you have to leap down onto the back deck, which is bouncing up and down with the swell. The thought of being crushed and then shredded is definitely on your mind: