Japan Oil Development Co. will file for court protection from creditors under the fast-track Civil Rehabilitation Law, with an estimated debt of more than 400 billion yen, sources said Tuesday.

Japan Oil Development was scheduled to convene a board meeting Wednesday and apply for the legal action with the Tokyo District Court later in the day, the sources said.

With no prospect for business improvement, the nation's largest oil development company, which operates under the umbrella of the government-affiliated Japan National Oil Corp., has abandoned efforts to rebuild its operations on its own, the sources said.