Here's a video on Casing and Cementing of off-shore wells

Even with cameras, once they pull up the drill string each time, how are they lowering it and getting it back in the hole each time ? (at the beginning, they do add casing pipe later, between the bottom and water surface) The water can be so deep that the drill-string will sway in the currents quite a bit I'm sure. So what sort of robotic thing is on the ocean floor to catch it, without getting smashed, and then put it back in the drill hole each time ? What year did they start under-water drilling ? Gravity alone might get you close to a 2ft target on the sea-bed, or lake-bed, in shallow water, but it won't stop you from missing or smahing up the "christmas-tree" once that's in place. And if the water is 1,000s of feet deep, the deflection angle can be pretty big, and what catches the drill-string without getting crushed ? So how do they do it ?

this video doesn't even mention the risk, every single time, of smashing the thing they place on the bottom

 

... I recall from someplace that deep water drilling platforms have a sophisticated positioning system, utilizing a feedback control system and multiple propellers to adjust the lateral position of the surface platform over the drill hole in a precise manner.
... There ought to be a video about it someplace.
Here is a related article:
https://en.m.wikipedia.org/wiki/Dynamic_positioning

 

Ok sure the ship's can stay pretty stable especially these days, but that's not what I mean

 

 

Ok so the riser pipes go from the seafloor assembly on the bottom, to the surface. And channels the drill string and fluids/etc.

So when they 1st arrive and there's no hole or anything, do they just put down the riser 1st, from bottom to top and run the drill/etc down it ? And then never really remove it I guess ?

What about if an exploration ship drills a hole, then caps it off and leaves it for a oil rig to be setup later. Do they remove the riser then? Or leave it with floats attached near the surface, or on the surface ? And then when the oil rig arrives , does some robotic arm have to go down and feed the new pipes/etc into whatever's left there....

What ever they do, they figured it out without beating up what's already down there, and without missing.

 

So when they 1st arrive and there's no hole or anything...

Come on, did you really thought they find a hole ready to tap? Are you trolling? It's not a video game.

 

No I'm just really wondering if at any time, after the whole process starts, does a ship/rig have nothing between the seafloor, and the surface, .....and so when they start lowering drill/pipes again, what lines it up and inserts it into the right place again, without missing, or crushing whatever they already placed on the bottom.

Maybe in the old days divers had to go down and line it all up

 

No I'm just really wondering if at any time, after the whole process starts, does a ship/rig have nothing between the seafloor, and the surface, ....

That does happen occasionally. Here's a story from 2010 or watch the movie.