Oil giant Royal Dutch Shell is to buy exploration firm BG Group in a deal valuing the British business at about £47 billion.
The companies unveiled details of the huge merger, the biggest in the industry for several years, in a statement to the London stock exchange.
The swoop by the Anglo-Dutch company comes as the oil industry looks to become more efficient and reduce costs in the face of falling energy prices. BG Group, which employs about 5,200 staff in 24 countries, was created in 1997 when British Gas demerged into two separately-listed companies.
Shell has confirmed it is planning to drill in Alaska in 2015, according to ITV News Business editor Joel Hills.
Energy company Shell has confirmed that its fourth quarter 2014 earnings have risen to $4.2 billion compared with $2.2 billion for the same quarter a year ago. On a "current cost of supplies" basis, full year 2014 earnings were $19.0 billion compared with $16.7 billion in 2013. In the firm's Q4 results, which come despite the cost of oil plummeting recently, it also noted savings of over £15 billion in potential spending over the next three years.
In it's full year update, Shell said it had options to further reduce spending, but was "not over-reacting to current low oil prices".
The cause of the fire and explosion that broke out at a Royal Dutch Shell chemical plant in the Netherlands late last night is still not known, according to a spokesman.
Royal Dutch Shell spokesman Thijs van Velzen said two people received minor injuries. "All the people that were present are safe," he added.
Mr Van Velzen said he did not know the cause of the fire.
Police and emergency services also said that the flames were dying down and smoke was rising straight up, but advised people near the plume to close their doors and windows.
The blaze was close to the scene of another major fire three years ago at a chemical storage facility.
A major blaze has broken out at a chemical plant operated by oil giant Shell near the Netherlands port city of Rotterdam.
Local police and fire authorities have said that nobody has been injured in the explosion or have yet been reported missing.
In this short video, reportedly of the incident earlier tonight, a fireball is clearly seen on the horizon.
A large fire has broken out a a Shell chemical refinery in the Netherlands, according to local media.
People nearby heard two huge bangs and saw a flash of light, the reports say.
It is not yet known if there are casualties or the extent of the damage.
Images on social media show a fireball rising from the plant which is in Moerdijk, south of Rotterdam.
Shares fell 4% after the profit alert, which comes after an already disappointing past few months for the Anglo-Dutch group.
Shell has blamed lower oil and gas prices and "weak industry conditions" in the processing and distributional of oil, as well as higher exploration expenses and lower volumes.
The group also said it expects hefty writedowns of 700 million dollars (£429 million) for the fourth quarter and 2.7 billion dollars (£1.7 billion) for the full year relating to its its upstream business.
These are expected to hit results even further, sending fourth quarter earnings 70% lower to around 2.2 billion dollars (£1.3 billion) and 2013 earnings 38% down to about 16.8 billion dollars (£10.3 billion).
Oil giant Royal Dutch Shell has warned its results for the fourth quarter of 2013 are expected to be "significantly lower than recent levels of profitability".