“Russians treasured the fact they had a monopoly on oil and gas pipelines from Central Asia, as it gave them considerable clout,” said Marshall I. Goldman, a senior scholar for Russian studies at Harvard and the recent author of “Petrostate: Putin, Power, and the New Russia.” “By agreeing to having an oil pipeline, Georgia made itself more vulnerable.”

A big concern for the future is what will happen to oil from Kashagan, the giant oil field in the Caspian Sea that holds over 10 billion barrels of reserves. Located off Kazakhstan, Kashagan is the most ambitious attempt to date by Western companies to develop new supplies in the Caspian. It will be at least five years before oil starts flowing from there, but the operating consortium, which includes Exxon Mobil and ConocoPhillips, plans to transport some of Kashagan’s oil through the BTC pipeline.

That would involve building a new pipeline under the Caspian to connect to BTC. Russia has opposed similar plans in the past.

Image The BTC pipeline was designed to avoid Russian interference. Credit... Marco Longari/Agence France-Presse — Getty Images

The Baku-Tbilisi-Ceyhan pipeline, 1,100 miles long, transports 850,000 barrels a day of oil, or one percent of global supplies, from Azerbaijan through Georgia and Turkey, ending at the port of Ceyhan on the Mediterranean. Much of the oil is bound for Europe and the United States.

The oil comes from several fields in Azerbaijan, offshore in the Caspian. The line, which cost $4 billion to build, also carries some oil from Tengiz that is barged across the Caspian.

Before the BTC pipeline was built, the West struggled to find routes that would avoid what Western leaders considered to be potential trouble spots, but it was difficult. The United States did not want the line to pass through Iran, for instance. In the end, the United States government, BP, which operates the pipeline, and other private investors decided the line should proceed on its current route. That gave a boost to newly independent counties and to Turkey, an ally, but it also sent the line through three nations struggling with separatists.