DUBAI, **v 18 (Reuters) - Saudi Arabia's Advanced Petrochemical Co. has completed the sale of a 1 billion riyal ($266.5 million) Islamic bond, the company said in a bourse filing on Tuesday, its debut sukuk issuance. The five-year offering received investor orders worth 2.43 billion riyals and was sold to government entities, insurance companies, investment and money market funds, companies and financial institutions, the statement said. ...