Standard and Poor's meanwhile said Tuesday that it views Noble's recent profit warnings as credit negative. It downgraded Noble to junk from investment grade in January.
S&P will assess the full rating impact following Noble's full-year results on Thursday.
"The downgrade reflects the impact of the unexpected assets write-down on Noble's business and financial profile," said Moody's senior credit officer, Joe Morrison.
Moody's estimates the write-downs will increase Noble's adjusted net debt-to-net capitalization to about 58 percent at end-2015 from about 51 percent at end-September 2015.
"The asset impairment significantly heightens uncertainty regarding its ability to achieve adequate profitability and cash flow, given our expectation of a prolonged commodity down-cycle, and the consequent negative impact on its relationships with banks and counterparties," added Morrison.
The rating review reflects concerns regarding progress in resolving its liquidity issue as well as the consequences of the impairment charges, Moody's added.
Although Noble's sale of Noble Agri will improve the company's liquidity profile, its liquidity position will "remain constrained" until it refinances approximately $1.6 billion in bank facilities due in May, the ratings agency said.