The firms' bosses told a Doha press conference that their North Oil Company would operate the field from July 14.
Qatar Petroleum chief executive Saad Sherida Al-Kaabi told the AP there's "a strong possibility" that the geological structure in the area where the partnership is licensed to drill could potentially hold hydrocarbons.
Qatar declared a moratorium in 2005 on the development of the North Field, which it shares with Iran, to give Doha time to study the impact on the reservoir from a rapid rise in output.
Saad Al-Kaabi - who heads state-owned QP, the largest exporter of Liquid Natural Gas and one of the biggest oil companies in the world - said today he expected US policy to remain similar to that exercised under previous presidents.
The reduction -- beginning on January 1 -- comes following the recent decisions by OPEC and non-OPEC oil-producing countries to cap output.
Under the terms of the deal announced, Chevron will hold onto a 45-per cent interest in the offshore leases, while Morocco will retain a 25 per cent stake. Qatar Petroleum says the Moroccan government has approved the deal.
Shell owns 50 percent of Parque das Conchas, its main Brazilian asset. Qatar's state oil company Qatar Petroleum owns 23 percent and India's ONGC owns 27 percent.
Qatar Petroleum has expressed interest in buying a 5.2 per cent stake in Petronet LNG Ltd, a potentially conflict of interest proposition as it will give the gas supplier a vantage position in India's largest fuel importer.
A senior Libyan rebel official said on Sunday Gulf oil producer Qatar had agreed to market crude oil produced from east Libyan fields which are no longer in the control of Muammar Gaddafi.