Oil is formed from dead plants and animals that died 10-600 million years ago. After the organisms died the fell into the sandy mud at the bottom of the ocean. Over the years, the organisms have formed sedimentary layers that contain oil. The job of finding the oil in these layers is up to geologists.
Some techniques in finding the oil are: Gravity Meters to measure Earths gravitational field to see if any oil is moving/flowing. Seismology that creates shock waves to send through hidden rock layers. And finally there are magnetometers which measures changes in the Earth’s magnetic field.
Once the site has been selected, you have to survey it to find where the oil is exactly. You must then set up a rig and start to drill. There are five basic steps when you drill a hole, they are.
1. Attach the drill bit
2. Attach the Kelly and turntable to start to drill
3. While you drill, you need to circulate the mud through the pipe
to get rock cuttings out of the hole.
4. Add new drill pipes as the hole gets deeper
5. Remove everything and leave the ocean floor as untouched as possible.