I eat breakfast next to the guys from Schlumberger company. They dig 5.000 up to 15.000 metres deep holes into earth below the Indian ocean and pump out gas and oil. It's about 200 km out in the Indian ocean, east of Pemba. They fly out each day with helicopters after breakfast and come back in the afternoon. So like normal 8-hour working day. If somebody is interested into this kind of job, check their web page.