Argo Petroleum said it filed under Chapter 11.

The Santa Monica-based oil and gas exploration and production firm called it a “voluntary” filing under the U.S. Bankruptcy Code but said creditors would probably have forced its hand otherwise. Argo has been in default on terms of its loans, and Continental Illinois National Bank had demanded immediate payment of a $38.8-million loan. Argo is the latest victim of the oil price collapse, which has been especially damaging to independent oil firms. It reported a loss of $7.3 million for the January-March quarter after a full-year 1985 loss of $36.8 million.