Intelligent oil-wells

The equipment is supplied by a small SINTEF start-up company in Trondheim called ResMan as, whose work is based on many years of research at SINTEF and the Institute of Energy Technology (IFE).

It has taken about a year to develop the prototype for Statoil that has just been installed on the Urd field in the Norwegian Sea. Scientists believe that it will offer operating companies completely new possibilities for well control.

Water problems

“When oil is produced, all the fluids in the reservoir, including the water, start to move. Water in movement can have a planned positive function, because it can force the oil to move in the direction of the wells, thus increasing production. But there is still a great deal of uncertainty regarding just how water moves through a reservoir, and it often flows into production wells where it mixes with the other fluids. The result may be a reduction in saleable production, and in the worst case, serious well problems and operational shutdown,” says Fridtjof Nyhavn, managing director of ResMan as.

Unwanted inflows of water are the single most important factor causing production problems. A company such as Statoil alone produces enough water to fill a 350,000 tonne tanker a day. Much of this water could be replaced by saleable oil if measures to prevent water from flowing into the wells were implemented. Information about just where water flows into wells is a fundamental requirement for planning such measures. At current oil prices, even a one percent increase in Norwegian oil production would be worth NOK 4 billion a year.

“We decided to test this technology on Urd as we regard it as an extremely useful tool for the future,” says Statoil’s Sigurd Hundsnes.

The system

The ResMan system consists of a number of plastic staves, which are installed in the well in the production zone. The staves are doped with tracers that are unique to each section of the well, and these tracers are liberated if the plastic staves are surrounded by water. As long as there is only water in the well the tracers will not be liberated. It is this liberation of tracers – controlled by condition and environmental conditions – that is described as “chemical intelligence”. Measurements using chemical intelligence can be made without having to send any sort of cabling down the well.

Once it has been fully developed, the ResMan system will provide information about what is flowing, where, and in what quantities, at the interface between reservoir and well, but also internally in complex well completions.

“The pilot tests on Statoil’s field are extremely important for us,” says ResMan’s director of development Anne Dalager Dyrli. “We have demonstrated the system in the laboratory under conditions similar to well conditions, and we have produced sufficient plastic staves at full scale to meet the needs of a complete well. All of these steps, up to installation in a well, have taken place without any problems worth mentioning. The fact that production is now under way according to plan on the field shows that the ResMan system in the well situation has no negative effects on production and that the downhole parts of the system are functioning properly. The measurements (topside aspect) will be demonstrated in the event of a subsequent water breakthrough.