The documents, seen by the BBC and the Bureau of Investigative Journalism, relate to proceedings brought in London by a company owned by Russian billionaire Chalva Tchigirinsky, who claimed the oil fields had been stolen from him and other investors.
At the time of the case, Tenenbaum was helping to manage Abramovich's wealth and gave evidence during the proceedings. The leaked documents now suggest there was a premeditated attempt by Abramovich to reduce the value of the other investors' stake in the Siberian venture.
The dispute centred on oil fields developed jointly between Abramovich's company, Sibneft, and the Russian subsidiary of the British company Sibir Energy PLC, owned by Tchigirinsky. Sibneft contributed money, while the subsidiary Yugraneft provided the licences for the oil fields.
The partnership, known as Sibneft-Yugra, ended acrimoniously. Sibir's 50% interest in the joint venture had been diluted to less than 1%, which it said was done without its knowledge. Unsuccessful attempts to sue Sibneft in both Russia and the British Virgin Islands led to the court proceedings in London.
At the 2008 hearing, Yugraneft claimed to have been the victim of a massive fraud directed by Abramovich.
Roman Abramovich's lawyers say their client denies all the allegations made against him. Lawyers for Tenenbaum say he denies in the strongest terms any suggestion that he committed perjury or contempt of court.