Offshore drilling rig operator Paragon Offshore PLC filed for chapter 11 bankruptcy Sunday, with an agreed turnaround plan that will reduce its debts by about $1.1 billion. A casualty of plummeting oil prices, Paragon announced on Friday that it intended to file for bankruptcy protection, to implement a restructuring strategy supported by unsecured bondholders and senior lenders. Sinking oil prices have slowed drilling and…