Some oil companies might want to induce North Sea earthquakes to improve the flow of oil or gas. The tremors could become more common as many fields reach their maturity and oil companies turn to secondary recovery techniques to maintain or extend production. The most common method used in the North Sea is to pump sea water into the reservoir. A chemical gel is often added to the water. Rocks, in some cases weakened by chemical corrosion, can rapidly rupture as a result of physical stresses caused by the influx of sea water.