• Shares of Petroleos Brasileiro SA are now trading on the New York Stock Exchange as American Depositary Receipts as PBR, making Petrobras the world's seventh-largest publicly traded oil company. • Burlington Resources Inc., Houston, has entered West Africa with the acquisition of a 25% interest in the AGIP-operated M'Polo, Chaillu and Meboun blocks, covering 5.3 million acres in offshore Gabon. • Triton Energy Ltd., Dallas, has acquired a 38% interest in the Tolo and Otiti blocks offshore Gabon. Its partners in the two blocks are Australia-based Broken Hill Proprietary Co. Ltd., the operator, and Sasol, a South African company. • CanArgo Energy Corp., Calgary, has concluded an agreement with JSC National Oil Co. and the state agency for the regulation of oil and gas resources of Georgia on its participation in the Norio Block XIC in eastern Georgia. The agreement mandates that CanArgo will be granted a one-year right to negotiate exclusively for a production sharing contract for the block. -Heather H. Read