The company will now increase its working interest in the project to 30%.
The field development plan was approved in June 2010 and first oil is expected in mid-2011.
Endeavour said that the Bacchus project remains on schedule, and the pipeline riser has been installed on the Forties Alpha platform.
The 6.5km subsea bundled pipeline construction has been completed.
The bundled pipeline and its end manifolds are scheduled for launch from Wick on the East coast of Scotland in early March.
