Net profit was down more than 50% to $713 million, but above expectations of around $413 million, and core earnings were down 41% to $2 billion and pre-tax profits were down to $890 million from more than $2 billion a year earlier.

BG is subject to a $90 billion takeover offer from Shell, which is likely to be completed next year.

Shell must be happy with its offer, which looks slightly more attractive than it did last year.

Oil prices have risen 20% since Shell lodged its bid for BG, and BG has doubled its LNG earnings forecast for 2015 to between $1.6-$2 billion.

BG's LNG unit, one of the main pillars of the business which Shell said justified its takeover offer, ramped-up volumes in the first quarter, selling 21 more cargoes than the same time last year thanks to the newly opened $25 billion Queensland Curtis LNG facility in Australia.

The group also ramped up oil production in Brazil.

BG has also said that a reduction in the pipeline tariff means the sale of the QCLNG pipeline to APA Group will raise slightly less than the $6.3 billion expected.

BG CEO Helge Lund, who came across from Norwegian state-oil giant Statoil, says BG remains happy with the Shell offer, and he says he is working to deliver BG in tip-top shape to its would-be owners, and he does not expect a counter-offer to Shell's proposal.

But his words are ominous for BG's 5000 staff, some of whom will be facing the chop following the merger.

He has urged Shell to adopt a "merit-based" selection process in integrating the thousands of employees whose jobs could be at risk following the takeover.

Separately, the managing director of Iran's Pars Oil Company claims Shell has voiced interest to resume activities in the country's energy sector, with indirect talks underway even though the international sanctions on Iran are some way off being lifted,

Iran's oil exports have been cut by more than 50% to nearly 1.1 million barrels of oil per day from a pre-2012 level of 2.5MMbopd.

Shell is one of several large oilers keen to get involved in new oil contracts with Iran, primarily from Europe, China and Russia.

Iran expects to unveil its new oil contracts in September.

The new format of Iran's oil contracts will be a modification of the traditional buy-back risk service contracts and has been specifically designed to increase the attractiveness of Iranian oil projects for foreign investors.