A vessel for exploration of hydrocarbons includes one or more risers extending from the vessel to the seabed, a hydrocarbon processing unit connected to the one or more risers and to a storage or transport structure for storing the processed hydrocarbons. The vessel is anchored to the seabed, the vessel includes a lifting member for lowering risers vertically towards the sea bed and for connecting a riser with a first end to a subsea hydrocarbon structure, which riser includes a connector on a second end, the vessel having a connector for attaching to the riser connector and for placing the riser in fluid connection with the processing unit.