Niska Gas Storage Partners LLC, the natural gas-storage company whose value has collapsed from over $1 billion to just $80 million as energy prices slumped, is exploring a sale, people with knowledge of the matter said.

Niska, controlled by private equity funds Riverstone Holdings and Carlyle Group LP, is working with Evercore Partners Inc. to find a buyer, said the people, who asked not to be identified because the matter isn’t public.

The sale is part of a broader restructuring effort that’s come as Niska struggles to revive its prospects amid a natural gas glut. In February, the company ceased distributions to shareholders to preserve cash.

Niska is one of many small companies in the energy industry, from explorers to oil-services providers, that have struggled as oil prices halved since June. Companies are slashing spending, suspending projects, and laying off workers to preserve cash -- while they look for investors still willing to bet on a recovery.

Niska stores gas for energy producers, investors, and power companies that want to hold onto it until cold weather or other factors push up demand -- and prices. The problem for Niska: a surge in gas production on the East Coast of the U.S. and elsewhere means customers aren’t stockpiling as much gas as they used to.

Amid the energy-price slump, Niska’s share price has fallen from a closing high of $16.32 last May to below $2 more recently. The shares rose 6.6 percent to $2.11 as of 12:15 p.m. in New York, giving it a market value of $80.2 million. Any buyer would also have to absorb nearly $827 million in debt, data compiled by Bloomberg show.

Riverstone and Carlyle control about 54 percent of Niska’s outstanding shares, according to data compiled by Bloomberg. They acquired the business from Canadian oil and gas company Encana Corp. for about $1.5 billion in 2006, data compiled by Bloomberg show. The company raised $413 million in a 2010 initial public offering, pricing its shares at $20.50.

A spokeswoman for Niska declined to comment. Representatives for Evercore and Riverstone did not return phone calls seeking comment. A spokesman for Carlyle Group referred questions to Riverstone.

Niska, which describes itself as the largest independent provider of natural gas storage in North America, reported a loss of $260 million in the quarter ended Dec. 31, compared with $13.3 million a year earlier.

Boardwalk Pipeline Partners LP and Crestwood Midstream Partners LP, which also provide gas-storage services, have also struggled, but they are less vulnerable than Niska because they are more diversified.