The company, based in Denver, spent $3 million on rig lease buyouts, counted $10 million in merger-related costs and write-downs of $77 million among the overall contributors to the nets loss for the three months ending June 30.
President and Chief Operating Officer Patrick McDonald said in a statement his company's planned merger with Sabine was on pace and was included as one of the bright spots during second quarter 2014.
"Our proposed merger with Sabine continues to progress in a timely manner and we are working diligently to complete this transaction during the fourth quarter," he said Monday.
Sabine and Forest announced an all-stock transaction in May that combines their assets in East Texas, including the Eagle Ford shale basin.
In an August productivity report, the U.S. Energy Information Administration says Eagle Ford shale is on pace to produce 1.48 million barrels of oil per day and 6.5 trillion cubic feet of natural gas per day in August, making it one of the premier shale reserve areas in the United States.