(Adds background, output details)
By Marta Nogueira
RIO DE JANEIRO, Jan 19 (Reuters) - Brazilian oil and gascompany HRT Participacoes SA reached an agreement tobuy offshore assets of Royal Dutch Shell Plc in theCampos Basin, a source with knowledge of the deal said onMonday.
Further details of the agreement are expected to bepublished by HRT on Tuesday on the website of CVM, the localmarket regulator.
Bloomberg News, citing two people with knowledge of thematter, reported that the deal would give HRT 80 percent of theventure.
The fields involved in the deal are the Bijupira and Salemaareas, which were some of the first to be operated by a foreigncompany in Brazil on a commercial scale, the source that spokewith Reuters said.
Representatives of HRT and Shell said they do not comment onmarket rumors and declined otherwise to comment.
Shell operates the two areas with an 80 percent stake, whileBrazil's state-run oil company Petrobras holds theremaining 20 percent.
Combined, the two fields produce 30,000 barrels of oil aday, according to a Shell representative, more than four timesthe 4,300 bpd that HRT said it produced during the month ofNovember from its own wells.
HRT, which started selling stakes of its onshore natural gasprojects in the Solimoes Basin in the Amazon in 2011, has beenlooking to expand its offshore operations.
The current sharp decline in international oil prices havegiven smaller oil companies such as HRT a chance to pick up lessattractive assets that oil majors have been keen to shed in thecurrent market.
Shell recently revised its development plan for the twoageing fields to reduce the natural slowdown in their output. In2013 and 2014, it drilled four new wells in the Bijupira andSalema, giving them 12 wells and six injectors. (Reporting by Marta Nogeira; Writing by Reese Ewing; Editing byDiane Craft and Lisa Shumaker)