Lets assume a departure from a runway with no published SID no emer/compulsory turns published.
If there is no published SID, you're on your own unless your company has crunched the numbers on all relevant obstacles in the vicinity. It could be a very big mistake to simply assume that there are no relevant obstacles along your climb path.
In any event, ATC is not responsible for your clearance from obstacles. They issue take-off and route clearances on the basis that you will avoid obstacles for yourself. This is certainly the case in many developing countries, where they might not even have an up-to-date Annex 14 survey.
Your company really should provide you with procedures for this situation so that you know where the relevant obstacles are and, more importantly, how to avoid them.