(Corrects day in paragraph 2 to Thursday)
TOKYO, July 30 (Reuters) - Idemitsu Kosan Co Ltd,Japan's second-biggest refiner, has agreed to buy about a 33percent stake held by Royal Dutch Shell in fifth-rankedShowa Shell Sekiyu for about 160 billion yen ($1.3billion), the Nikkei business daily reported.
The deal will be announced later on Thursday, the Nikkeisaid.
Showa Shell shares soared as much as 13 percent on thereport, while Idemitsu fell 3 percent.
Showa Shell was not immediately available for comment. AnIdemitsu spokesman declined immediate comment.($1 = 124.0900 yen) (Reporting by Chris Gallagher and Osamu Tsukimori; Editing byChang-Ran Kim)