Mayor Michael Nutter released a report Monday that indicates selling Philadelphia Gas Works could yield a profit of $146 million to $496 million under the best-case scenario.

The sale would include conditions such as honoring current employee contracts and keeping the corporate headquarters in Philadelphia for a period.

The report says the sale process could take about two years. It would require state approval.

Gas Works spokesman Barry O'Sullivan says the utility has transformed itself in recent years from a financially troubled company into an attractive business. It has more than 1,600 employees.

The cash-strapped city asked Lazard to evaluate the options for the utility in July 2010.