DUBAI, June 19 (Reuters) - Qatar Navigation (Milaha) QNNC.QA has reached a preliminary agreement to buy Qatar Petroleum's stake in oilfield services firm Al Shaheen Holding, Milaha said in a bourse filing on Sunday.

Qatar Petroleum hired HSBC in February to advise it on the sale of Al Shaheen as the state-owned Qatari energy giant, grappling with low oil and natural gas prices, seeks to divest from non-core businesses.

Al Shaheen has three joint ventures in oilfield services, two with GE Oil and Gas and one with the Middle East unit of Weatherford.

Qatar Navigation said a binding agreement for the transaction had not been finalised but the deal was expected to be in the range of $110 million to $180 million and would be funded from existing cash reserves. Subject to due diligence and a final agreement, the transaction could close in the fourth quarter of this year, the company added.

(Reporting by Hadeel Al Sayegh; Editing by Andrew Torchia) ((Hadeel.AlSayegh@thomsonreuters.com; +971566883310;))