BUCHAREST May 6 U.S energy major Chevron has begun drilling for shale gas at its exploration well site in eastern Romania, the company said on Tuesday.
Chevron won approval to drill exploratory wells in the small town of Pungesti in the impoverished Romanian county of Vaslui last October but had to halt work when protesting residents blocked access to the site.
It resumed work in December, and drilling began last Thursday after completing safety and performance checks, the company said.
"Various measurements and rock samples will be taken to determine if natural gas is present and how it may be produced," Chevron said in a statement.
The U.S. Energy Information Administration estimates Romania could potentially hold 51 trillion cubic feet of shale gas, which would cover domestic demand for more than a century.
But hundreds of residents in Vaslui protested against Chevron's plans on concerns that the company would use fracking - the process of injecting water and chemicals at high pressure into underground rock formations to push out gas.
Critics, including the Romanian protesters, say it can pollute water supplies and trigger small earthquakes. Advocates say it has a strong safety record and point to countries like the United States, where extensive fracking has driven down energy prices.
Chevron, which also has rights to explore three licence blocks near the Black Sea, does not have plans to use fracking - - under its five-year exploration programme. It says it is abiding by all safety regulations.
(Reporting by Radu Marinas; editing by Susan Thomas)