It don't rain but it pour. Or, in the case of oil, it don't trickle but it gush. The world has recently been awash with tales of oil bonanzas in far-flung corners of the globe. A cold shower is now in order.

Two weeks ago BP announced a “giant” find in the Gulf of Mexico. BG Group has celebrated two finds in the pre-salt area off Brazil in just the last 10 days. On Wednesday, Anadarko announced positive results from the Venus well off the coast of Sierra Leone. The significance here is not so much what Venus may produce, but what it says about the prospectivity of the wider region. Executives enthuse that the chances of success in an arc stretching from Sierra Leone to Ghana's deepwater Jubilee field have increased, at a stroke, from 5 to 25 per cent.

All numbers in the oil industry – from the odds of discovery to the scale of reserves – are uncertain. Still, it is easy to understand why these latest – unconnected – finds have caused excitement. For small companies they can be transformative. Even for giants like BP, the discovery of a new field is a major event, shoring up its reserve base.