Canada's oil and gas companies continue to reel from the industry downturn. Encor could be in breach of loan covenants by midyear and is in the midst of debt restructuring plans with lenders. It has hired an investment banker to seek a merger or a takeover offer. Encor reported a loss of $89.7 million (Canadian) for 1991. Western Geophysical. Calgary, a unit of Western Atlas, Houston, is being closed down by its parent because of depressed activity levels.