Small and medium-sized oil companies, squeezed by the oil price slump, may have to raise expensive new finance, sell assets or seek new investors to plug any funding gaps as banks tighten up on lending.
Many of these companies have already cut spending and axed thousands of jobs following a more than halving in the oil price to around $50 a barrel since June last year.
But they may need to do more as revenues fall and the oil price looks set to stay low. Oil's fall last month to its lowest since early 2009 at just above $40 a barrel has dashed hopes in the oil industry for a swift recovery.
In many cases, banks lend money based on a company's oil and gas reserves base, in what is known as reserve-based lending, so, in theory, the lower the oil price outlook, the smaller the loan or credit line.
"Banks will be broadly supportive but for some riskier clients and transactions, there may be a gap in financing that didn't exist before and they will have to find alternative financing," one banker, who heads a loan syndicate, said.
"There is concern that banks will redenominate and reduce existing financing for energy companies. Banks are looking at this now, it's a live issue."
The companies and their banks sit down twice a year to review finances, which used to be a fairly routine conversation when oil was riding high. Most companies emerged from the April round of talks, known as "redeterminations" relatively unscathed because of expectations of an oil price recovery.
The current round may be more difficult as banks will have cut their long-term oil price forecasts, according to several bankers and consultants.
"Managements and boards have had to come to terms in recent weeks with the 'lower for longer' oil price view," Rupert Newall, head of EMEA energy investment banking at BMO Capital Markets, said.
Exploration and production companies with large project financing needs include Africa-focused Tullow Oil, North Sea producers Lundin Petroleum and Ithaca Energy , according to bankers and analysts.
Nomura has estimated Tullow Oil's net debt will rise to $4.7 billion by the second half of 2016, when its TEN project off Ghana's coast is planned to start production.
Tullow's net debt at the end of the first half of 2015 was $3.6 billion.
Tullow and Ithaca declined to comment. Lundin did not immediately respond to requests for comment.
In the United States, where some oil companies borrowed heavily to invest in shale, several have run into trouble this year, including Oklahoma-based Samson Resources.
But Jo Clark, a transaction advisory consultant at EY, said the chances were low of similar problems in Europe.
There have been a few casualties. Oil producer Afren , for example, decided to go into administration in July when it failed to win support for a refinancing plan.
Credit rating agency Standard & Poor's on Thursday cut its long-term corporate credit rating on British oilfield services company Expro Holdings Ltd to CCC+ from B-, citing its high leverage and the challenging market conditions in oil and gas.http://www.reuters.com/article/2015/09/17/oil-companies-debt-idUSL5N11A2HR20150917