MELBOURNE (Standard&Poor's) Dec. 3, 2010--Standard&Poor's Ratings Services today said that it had lowered its corporate credit and associated debt ratings on Woodside Petroleum Ltd. (Woodside) to 'BBB+' from 'A-'. The outlook is stable. The downgrade follows a further delay and higher costs for Woodside's Pluto project. "In our opinion, further delays and cost overruns for Pluto will hinder a timely recovery in Woodside's credit metrics to levels we expect for the 'A-' rating, especially positive free operating cash flow after capital expenditure," Standard&Poor's credit analyst May Zhong said. "Furthermore, the project delay means that the gap between completing Pluto and Woodside moving forward with other growth projects may be shorter, providing less time to