* BP controlling wells at Valhall offshore field from land
* Other oil companies considering following suit
* Norway is testing ground for new method
(Reuters) - Oil and gas companies are moving their control of some offshore platforms to offices on land to cut costs and improve efficiency, but labour unions say such moves reduce safety.
Some oil companies already monitor platforms live from land to assist offshore crew. They can also remotely control small unmanned platforms and subsea production units.
Now they are starting to control some operations of larger, manned platforms, and Norway, the world's seventh-largest crude exporter, is serving as their testing ground.
Unions say the move endangers safety, a top focus of regulators and the industry since BP's Macondo accident in the Gulf of Mexico in 2010, which killed 11 people and resulted in a massive oil spill.
"Would you board a plane without a captain?" asked Christopher Birknes, a representative of trade union Industri Energi at BP.
"What happens if there is an emergency situation and communication is lost between the platform and the onshore control room?"
Leading the way is BP, which has moved control of the oil and gas wells at the Valhall field in the North Sea to its head office in Stavanger some 350 km away (217 miles).
There is still a control room at Valhall, where processing, injection activities and the monitoring of safety systems takes place. If all goes well, however, BP says it may move control of injection and processing activities onshore, leaving only the monitoring of safety systems offshore.
Total plans to control from land the platform at its Martin Linge field, which is due to start production in 2016. Statoil also is considering whether to transfer some control room activities onshore.
Safety has been a focus in the North Sea in recent years. In 2012, a gas leak at Total's Elgin field in the British section of the North Sea took weeks to get under control. Production was shut for 11 months.
In Norway, oil safety regulator Ptil told BP in April it must review the way it handles risk and maintenance at offshore installations following a leak at the Ula platform, which could have caused a major accident.
SPECIALISTS ON HAND
BP says the new procedure enhances the management of production operations and increases safety, with engineers at the head office on hand to assist the control room operators, who are in live contact with their offshore colleagues.
"In the old days, you would have to fly out specialists. This will save us time and money," BP Norway spokesman Jan Erik Geirmo said.
Total said land-based control of its Martin Linge field would mean fewer people offshore to evacuate in case of an emergency.
"We could evacuate them quicker if something happens as we would need to fly fewer helicopters," spokesman Leif Harald Halvorsen said.
Oilfields in Norway tend to be smaller than years ago after companies depleted the biggest fields, putting pressure on firms to find ways to cut costs.
Costs off Norway are expected to increase 6 percent per year until 2016 due to increased prices for equipment, material and labour, according to a 2011 report by the Norwegian oil industry lobby group.
"We need simpler and simpler solutions," said Ivar Aasheim, Statoil's senior vice-president for field development off Norway. He said Statoil also was considering whether to move some control room activities onshore.
"It could happen in three to four years' time if we decide to go ahead with this," he said.
He added, however, that the company was conscious of the potential challenges and would not implement any solution if officials thought it would endanger safety.
"BAD FOR SAFETY"
Norwegian trade unions are up in arms about BP's changes at Valhall, which they see as a test case for the rest of the oil industry.
One criticism is that onshore operators are not on the platform, making it more difficult to communicate.
"To work in a team, you work better when you are near one another. If you are unsure, you can sit down and talk. You can't do it in the same way with someone far," said Dag Unnar Mongstad, a Statoil trade union official. "We do not feel safe."
Mongstad, who belongs to the Industri Energi union, is also concerned about information being missed, because control room operators onshore would not be working the same hours as offshore workers.
At Valhall, offshore staff work two 12-hour shifts 14 days in a row, while onshore staff work three eight-hour shifts on weekdays and two 12-hour shifts on weekends.
Onshore operators may not immediately notice things that happen on the platform because they are not there, critics say.
Birknes, the trade union official at BP, is also worried about the risks of losing communication between platform and land and of hacking attacks.
Industri Energi conducted a survey among members working at Valhall. Some 69 percent said they felt more unsafe after BP moved well control operations offshore, while 31 percent felt as safe as before. None felt safer.
All said they would fell less safe were BP to move all control room operations onshore.
But Industri Energi and another union, SAFE, have been unsuccessful in efforts to stop BP's changes at Valhall.
The Labour Ministry last week confirmed a decision by Ptil, the oil safety regulator, to approve BP's onshore operations and said that "systems are sufficiently robust to ensure the offshore control room (at Valhall) will always be able to perform a controlled shutdown (of production)".
"The guiding principle to approve BP's solution was that they can ensure safe operations of the Valhall field at any time. The authority considers that this is properly addressed," Ptil spokesman Oeyvind Midttun said.
By Gwladys Fouche and Nerijus Adomaitis