Royal Dutch Shell PLC and EnCana Corp. are looking for a partner to develop 54,000 hectares of exploration leases in the Haynesville Shale area of Louisiana.

The companies are taking bids for as much as a 50 per cent interest in the properties through a data room, Calgary-based EnCana spokeswoman Carol Howes said in an interview. The proper-ties are in Sabine and Natchitoches parishes, on the southernmost part of the area the companies are exploring, according to Shell.

The companies aren't releasing financial details of the land offering, Howes said. The partner could gain an interest of up to 50 per cent in the properties, with Shell and EnCana holding an equal stake in the remainder.

"We optimize these kinds of land positions all the time," Howes said. "We go in, buy a large land position and optimize. There may be a deal, there may not."

The Haynesville play holds an estimated 50 trillion cubic feet of gas, enough to supply U. S. household demand for more than a decade, according to analysts at Calgary-based Ross Smith Energy Group Ltd. The formation straddles Louisiana, Arkansas and East Texas.

"This decision is no reflection on the value Shell sees in the Haynesville shale gas play, but rather is a means to expedite evaluation of the partnership's Haynesville Shale portfolio considering lease expiry outlook and allocation of resources," Shell spokeswoman Robin Lebovitz said in an e-mail from the company's Houston office.

Hague-based Shell is Europe's largest oil company.

EnCana will boost spending on its Haynesville properties to $290 million this year. Chief executive Randy Eresman said at a news conference last month the shale's proximity to U. S. markets and pipelines will help lower-cost producers in the region profit when gas prices rebound.

New York gas futures have dropped 26 per cent so far this year.

EnCana, Canada's biggest natural-gas producer, fell 15 cents to $61.05 on the Toronto Stock Exchange.