I personally think such study is definitely important considering environmental impacts when deciding whether or not to proceed with a project.
Secondly, in case such study is not made and it may result to major delays or maybe failure of the project. So its always a good idea to have this at planning stage so that any diversions, amendments etc. can be made at right time
I am not in the sector of the oil and gases, I am in the sector of IT, but any technical study make you expert in that technical field but not in the managerial field.
