Petrobras Singapore’s office, a representative of the Brazilian national oil and gas company, said it is moving to a new office from July 27.   Its new office will be at 435, Orchard Road, Unit19-05/06 Wisma Atria, Singapore 238877. Its telephone number is 65-67351140, while its fax number 65-67349087. Telex: 051 94076404 PSIN G.  …