Why Subsea ?

you dont need to build a jacket?

Best regards

Morten

Thanks MortenA,
Of course if we choose subsea completion, we will not need any jacket. But the cost to have some subsea completion are very high if you compare with others, especially if in life of field we have some problem with the well. To rent the vessel, they daily rate is amazing.

Regards
13392017

That's the payback. (+ no damage from hurricanes)

Actually, its usually the case that many jackets can be saved when you consider that multiple tiebacks can made to only one platform for wells up to a radius of what, 50 miles or so.

BigInch-born in the trenches.

Im no expert in this field. In Denmark we have few subsea compleations because the waters are shallow (<70 m). From what i have been told this means that the extra cost associated to cost of hydraulics and such means that small monocollumn jackets (that my company also designs are cost competetive. When adding to this that well intervention is more costly for sub sea and certaian operations cannot be performed without a drilling rig that might be possible on the minimum facilities platform then life cycle cost of the minimum facilities platform wins.

Best regards

Morten

Its only cost effective when the water is deep and platforms cost 500 MM+ In shallow waters, where you can put in a minimal "Seahorse" type structure for only a few million, its cheaper to put the wellhead control on the small deck and run a pipeline off of that.

In GOM there are probably more than 1000 platforms or minimal structures built in 50 ft or less water depth, but some drilling is being done now in 4000-5000 ft depths. Out in 3500 ft depths, fixed platforms generally are far too expensive to build unless the field is a GIANT, and totally impossible in 4000-5000 ft for any size field, so subsea becomes the ONLY option, with pipeline tie-backs to depths in which tensioned structures, or maybe a fixed platform can be built.

BigInch-born in the trenches.

Heres a link with some info on a typical "normally unmanned platform" in Denmark:


Best regards

Morten

Nice chart with 135 variations.
Can you find it?


BigInch-born in the trenches.

Nive They all look more or less the same to mee anyway

Best regards

Morten

Ha Ha me too!

BigInch-born in the trenches.

The other big area for subsea is marginal fields: leased FSPOs for example or where you have a satellite filed near existing infrastructure that cannot be drilled from that infrastructure either becasue it is just too far away or because there aren't any spare slots on the infrastructure.

However, the big problem of subsea is the difficulty of any kind of well intervention (I thnk there are only a handful of subsea wireline lubricators available worldwide), which is why all the work into TLPs, mini TLPs, spars, truss spares, deep draught floaters was done to get dry trees into the deep water.