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Space Technology Goes Underwater to Find Oil and Gas Fields

22 May 2012

Technology developed to measure the force of gravity in outer space has been adapted so that it can be used to prolong the life of the North Sea oil and gas industries.

Astrophysicists at Aberdeen University are developing the technology, which will pinpoint small unexploited oil and gas fields on the seabed.

Prototype trials will take place this year of gravitational sensors fitted to Remotely Operated Vehicles (ROV), which work at great depths under the water.

The sensors will be able to detect variations of density on the seabed, which indicate the presence of undiscovered oil and gas fields.

Dr Charles Wang, an astrophysicist at Aberdeen University, is leading the project which is being carried out in collaboration with subsea specialist companies Fugro Subsea Services and Trident Underwater Engineering (Systems).

He explained: "Current gravitational sensor technology is too large and too power-consuming to take underwater, and the equipment is not sensitive enough to operate in subsea conditions. And it makes perfect sense that the closer you are to the source of potential oil and gas discoveries, the more accurate you can be in detecting it.

"What we are developing is a new type of compact sensor that requires low power, and can be used in deep waters for the first time to detect new sources in a way that is more sensitive, accurate and therefore cost-effective.”

Dr Wang and his team have developed the sensor which they are now refining for use on ROVs and other subsea craft. It is based on technology which was first developed to measure micro gravity variations in space.

He said: "A small variation of gravity can be due to a small variation of density and this could be due, for example, to the presence of an oil field.

"The usual gravity we experience and understand is Earth’s gravity, but in reality every object is a source of gravity. If you have a sensor with high enough sensitivity, it will pick up small gravitational changes which indicate the presence of an object.

"It is this technology which has been used for decades in the oil and gas industry to detect the existence of prospective oil fields.

"But so far this technology has been limited to work above the sea level, with companies using gravity measurements as part of their airborne survey work. What we are doing here at Aberdeen is developing a new sensor which will allow gravity measurements to be used, for the first time, in a subsea environment.”

He explained that the key to the development of the new technology was the use of atoms such as Rubidium.

"When we cool these atoms to a super-cold temperature and trap them in an atom cloud, they act like a highly precise laser that can measure gravity in a way that is much more accurate than a normal optical laser could achieve. No mechanical parts are involved in the process so it is much simpler and more reliable.”

The technology is known as a "cold atom trap”. Dr Wang said: "It is this exact same science that we are taking from space and applying subsea in helping the industry find previously undetected hydrocarbons.”