Oil pipeline firm The Williams Cos. is expected to report higher fourth-quarter and yearend earnings Wednesday afternoon based on higher transportation revenues for expansion projects and higher profit margins on natural gas liquids.

The Tulsa, Okla.-based company is expected to report fourth-quarter net profits of $268.61 million, or 41 cents a share, according to analysts polled by Thomson Reuters.  The company earned $259 million, or 44 cents a share, in the year-earlier period.

Revenue is expected to be $2.77 billion, compared to $2.42 billion in the year-earlier period.

For the full 2011, Williams is expected to report earnings of $937.21 million, or $1.16 per share, compared to $760 million, or $1.28 a share, in 2010. Revenue is expected to be $10.64 billion, compared to $9.62 billion in 2010.

Williams spun off its exploration and production business into a new company, WPX energy. The company began trading on the New York Stock Exchange on Jan. 3.

Since then, Williams has laid out several expansion projects. Most recently, the firm placed the Pascagoula Expansion project, jointly owned by Florida Gas Transmission, into service in late September. Two other projects - the Mid-Atlantic Connector and Mid-South Phase I- are expected to be rolled out into next year.

Energy Transfer Equity in December won a bidding war against Williams for natural-gas pipeline company Southern Union. The $5.3 billion deal is expected to close within the first half of 2012.

Shares of Williams closed Tuesday up 35 cents (1.20 percent) to $29.46.