BOGOTA - Colombia's state oil company Ecopetrol said on Thursday it could seek up it $3.7 billion in debt this year, including issuing bonds on the international market, and is studying other types of credit.

Ecopetrol plans to invest $6.2 billion in 2009 and is looking to spend up to $10 billion to purchase assets overseas in the next six years as it expands its international operations.

Ecopetrol President Javier Gutierrez said the oil company was in the process of selecting an investment bank to lead any bond placement, but he did not give a date for a debt operation.

(Reporting by Javier Mozzo in Bogota, editing by Gerald E. McCormick and John Wallace)