The Trans-Caspian Oil Transport System is a proposed project to transport oil through the Caspian Sea from Kazakhstani Caspian oilfields to Baku in Azerbaijan for the further transportation to the Mediterranean or Black Sea coast. The main options under consideration are an offshore oil pipeline from Kazakhstan to Azerbaijan, and construction of oil terminals and oil tankers fleet. A strong push for the project has been from the partners of the Kashagan oilfield project and in particular Total who has a share in both the field and the BTC pipeline. They have estimated that such a project would cost roughly US$4 billion. The project also faces opposition from Iran and Russia, both alternative avenues for Kazakhstan's oil and gas who would likely object to competing pipelines being built.