under three weeks, page-24

The Cheval North well is in 2600m of water, and has to be drilled to a minimum depth of 1500m, according to ophir website.
The rig they're using is the Maersk Deliverer, which is brand new this year, so state of the art drilling may be cheaper.

Although the main reason would be drill depth, if the minimum level is 1500m, then I'm presuming they expect to hit oil around that depth, which makes sense because the CSEM they carried out returned very positive results. Therefore, one would presume the prospect is well within CSEM operating range ie less than 2500m (since maximum range is 2500-3000m below seabed).

Our southern fan prospect where shell carried out CSEM was inconclusive because of carbonates and depth limitations. I can't find any information as to exactly how deep our prospects off senegal are, if anyone knows please post.

So one can only presume our targets must be over 2500m below the seabed. So if ophir are drilling 1500m at 35mil it would make sense that our well, being 2500-3000m (or deeper) would cost 50-60mil. I'm pretty sure water depth doesnt really come into play since these rigs can operate in water up to 3000m deep anyway. The main aspect that would effect these figures would be the geology, something like harder rock taking longer to drill through etc.

On a side note, makes me wonder why shell bothered spending millions on CSEM when they knew there would be depth limitations associated with this method. Although I guess they didnt expect to have extensive carbonates bunging their readings as well.