A Brazilian conglomerate unveiled a proposal Thursday to build a multibillion-dollar natural-gas refining complex in West Virginia—the biggest such development in the state as it tries to profit from the region’s drilling boom. The proposed project by Odebrecht Group, a privately held São Paolo-based engineering, construction and petrochemical company, would include a plant known as an ethane cracker, where natural gas is turned into ethylene, a chemical-industry feedstock. The complex would also include three plants to produce polyethylene, which is used to make numerous products, from plastic bags to pipes. Odebrecht said the project is subject to securing both financing and long-term contracts to obtain ethane through pipelines, as well as regulatory approvals. A company spokeswoman declined to provide further details on the project’s cost or timing. Drilling in the Marcellus Shale and Utica Shale—massive natural-gas deposits beneath parts of West Virginia, Pennsylvania and Ohio—have made Appalachia one of […]