Again, without beating this to death, SDLP and Tullow have a signed contract. I haven't read it, but within that contract there is language specifying what constitutes 'Force Majeure' and what the remedy is in the case of a Force majeure event. The language of this clause is probably pretty clear and unambiguous.
Without having read it, these clauses exist specifically as escape clauses to deal with unforeseeable "act of God" type scenarios. A hurricane comes and sinks a rig. Suddenly, there is a war. Gov't acts to nationalize some assets, etc. The act in question, by the way, has to be both unforeseeable, and impossible to deal with. If there is some way of dealing with the situation, then it behooves the one under contract to try and rectify it instead of voiding the contract.
Key is UNFORSEEABLE.
Assuming it is what happened, once warned by the gov't of Ivory coast that it claims jurisdiction over a particular parcel, Tullow cannot credibly claim that IC disputing drilling there was unforseeable. It WAS forseeable, it WAS forseen, and Tullow was explicitly warned about it. If Tullow started drilling there anyway, then it assumes the risk of having done so, and it can't pass that risk onto the contract counterparty.
More specifically, having assumed a KNOWN risk here, it was Tullows responsibility to plan for this contingency, not invoke "Force majeure" and void the entire contract. In this case, I think there was is an agreed upon alternative arrangement, for a rig unable to work, namely for for Tullow to pay the downtime dayrate for this rig to Seadrill.
I'd add here that it actually doesn't matter whether or not Ivory Coast's claim has merit, either. Ivory Coast may eventually lose on this territorial claim, and Tullow may well be allowed back to drill in the exact same spot. The fact that it was likely to act on this claim was foreseeable, and therefore Tullow should have had a provision in place to deal with it.