Improved safety and more oil can be the result, if the problem of sand production is solved based on the properties of each well.
These are the conclusions of a pilot project carried out on the Gullfaks A platform in the North Sea.
Sand production in oil wells can lead to erosion and, at worst, holes in the flowlines. The limit for permissible sand production has therefore traditionally been low. For Gullfaks, this has led to production limits for over half the wells. Without these limits, production from the field could increase by approximately 30,000 barrels of oil per day, reports project manager Halvor Kjørholt.
Statoil has developed a new technology to calculate erosion in the wells based on production data. The project has shown that it is not appropriate to apply the same sand production limit to all wells.
Mr Kjørholt explains that the same amount of sand results in more than one thousand times as much erosion in wells with high flow rates – that is wells which produce a lot of gas with the oil – compared to wells with low flow rates.
Not only is erosion now being monitored in all of the wells. Two pilot wells have also got new sand rate gauges and permission to increase sand production. So far, these two wells have together produced an extra 3,000 barrels of oil per day.
“The results so far are better than expected, but the pilot project will continue until October. If results continue along these lines we hope to be able to adopt the technology on the entire Gullfaks field and in time on other Statoil operated fields,” says Mr Kjørholt.