Quicksilver Resources Inc. and its U.S. units filed for chapter 11 protection on Tuesday, adding to a list of oil and gas producers who have folded amid low oil prices, Reuters reported yesterday. The company listed assets of $1.21 billion and liabilities of $1.35 billion in its bankruptcy petition in a Delaware court. Quicksilver said that its Canadian units were not included in the chapter 11 filing. Quicksilver Resources Canada Inc. has signed an agreement with its lenders for forbearance until June 16, 2015, of any default under the agreement arising from the chapter 11 filing. The case is In re Quicksilver Resources Inc., Delaware Court, District of Delaware, Case No. 15-bk-10585.