Laredo Petroleum says it would sell its stake in a Permian pipeline unit for $825 million. : Oct 2 (Reuters) - Oil and gas producer Laredo Petroleum said on Monday it would sell its stake in a Permian pipeline unit for $825 million, lower than some industry estimates and prodding the company's shares down nearly 8 percent. Laredo and private equity firm Energy & Minerals Group said they would sell the unit, Medallion Gathering & Processing LLC, for $1.83 billion to infrastructure fund Global Infrastructure Partners.