I would imagine oil drilling costs are roughly the same unless of peculiar circumstances. That is why low global oil prices are bad for capital investments in new oil rigs.

Its lunacy that something that costs less than Usd 20 on average should sell for over usd 100 at final consumption.

Kenya's and Uganda's oil are likely to cost less than Usd 20 as they are onshore. I am assuming thats coz many onshore extractions cost less than that.

average break even cost would around $50 per barrel but you need $90 for the explorers to compensate for the risk of exploring a new frontier. The saudis care because they need oil at $90 to balance their budget but they need some shale oil producers to go bankrupt to cut off competition.

Oil boom will not end soon because by 2030 consumption will outstrip demand by far. This is a temporary price correction likely to end in 2018

All sub Saharan oil producing countries are suffering budget deficits and lower than expected revenues due to the fall in oil prices.
Nigeria had initially budgeted with crude prices at $90 which was revised downwards to $73 when the 78 mark was breached.
Last week they revised downwards to $65 when OPEC couldn't agree on oil production cuts.Now its at $66 I don't know what next for them.
Same case applies to Angola and equatorial Guinea who also together with Nigeria were major exporters to America but now America is no longer buying their oil.
Nigeria wanted to start selling oil to S Africa but they couldn't agree because to S Africa its cheaper buying oil from Iran than Nigeria.
Meanwhile the glut continues

Now this is going to be one of the most interesting high stakes poker games ever. @Quicksand, as you are saying, the Saudi Arabians are happy to keep the international prices low so as to drive capital away from US shale investments, including research.

Saudi has enough cheap production and can afford the steep price cuts, plus most of their oil revenues go into sovereign funds.

Other Opec countries like Nigeria, Venezuela and Angola have very expensive deep sea wells and generally consume all their oil revenue, so they are facing huge budget deficits, their problems are compunded by the fact that they cannot increase production due to a supply glut.

Where does this leave Russia, their oil production also happens to be very expensive but they have huge supplies. They are likewise loosing.

For the new oil frontiers like Kenya, TZ and Mozambique, its a mixed bag. I think for Kenya, the gava is very committed to seeing production plus our finds are onshore and easily accessible. For Mozambique and TZ, those huge gas deposits are in real deep waters and may hav eto be placed on ice until the market settles.

But you are forgetting that tullow and africaoil borrowed to fund the exploration in turkana field and GoK took on eurobonds in the hope of paying back when the oil from turkana kicks in 2017

Now crude oil at $50's this is headed to 30's

Where is the infrastructure? You have no roads leave alone the pipeline how do you expect them to export? FYI before they start pumping out oil, they have to know how big the resource is, is it worth the investment?