RIO DE JANEIRO (Reuters) - HRT Participações em Petróleo <HRTP3.SA> and its Anglo-Russian partner TNK-BP <TNBP.MM> signed an accord with Brazil's state-led oil company Petrobras <PETR4.SA> to draw up a plan to sell natural gas from their Amazon fields, HRT said on Monday.
The companies agreed to develop a plan to "monetize" HRT gas within 30 days and have six months to complete their work, HRT said in a securities filing. HRT, later in the day issued a separate statement to confirm the accord. Its shares rose as much as 10.5 percent.
On September 17, HRT Chief Executive Marcio Mello told Reuters he planned to define how he would sell, or unlock value from gas fields the company had found in Brazil's Solimoes basin west of Manaus, Brazil by the end of 2012 and sign a contract to sell it by the end of 2013.
Petrobras already operates natural gas and oil fields in the Solimoes basin and has the region's only natural gas pipeline. In September Mello said he is considering plans to build petrochemical plants and electricity generation facilities near HRT's fields in the Amazon.
HRT shares were up 9.42 percent to 4.88 reais in Sao Paulo and are on track for their highest close since September 3.
Petrobras officials were not immediately available for comment.
(Reporting by Jeb Blount; Editing by Gerald E. McCormick; editing by Carol Bishopric)