By a Newsnet reporter
Petroleum giant BP has unveiled a new technology which will increase the amount of oil that can be extracted from oilwells. The new technology will first be put into operation in the St Clair Ridge oilfield west of Shetland, where it is expected to produce an extra 42 million barrels compared to older techniques. The new technology will greatly improve the efficiency and lifespan of oilfields.
Crude oil in an oilfield must be under pressure in order to be pumped to the surface. The natural pressure in an oilfield, caused by the immense pressure of the overlying rock, is typically sufficient to pump only around 10% of the oil contained in the field to the surface.
Oil companies have long used a technique of pumping sea-water into the field in order to boost the pressure on the oil and increase the amount they can extract, however even this method means that around two thirds of the crude remains in the oilfield.
The new method developed by BP involves removing much of the salt from the sea-water before pumping it into the oilfield. Water which is too salty causes the crude oil to stick to the surrounding rocks. The new method reduces this natural "stickiness", and permits a greater quantity of crude to be pumped to the surface with the same water pressure.
Called Low Salinity Enhanced Oil Recovery (LoSal® EOR), the new technique is expected to make a significant contribution to extending the lives of existing oilfields. BP will be investing £75 million in desalination equipment for the Clair Ridge field, after successful trials of the new extraction method in oilfields north of Alaska.
Head of upstream technology at BP, Jackie Mutschler, explained:
"Oil industry wisdom says you shouldn't inject anything too 'fresh' or the clays within the oil-bearing sandstones can swell and reduce the ability of the oil to flow.
"So BP looked at the fundamental chemistry which makes the oil molecules stick to the rock surfaces in reservoirs.
"What we discovered is that by reducing the salinity, and hence the ionic concentration of the injected water, more molecules of oil could be released from the surface of the grains of the sandstone rock in which they're held."
Bob Fryar, BP's executive vice president for production, said:
"LoSal® EOR and other technologies developed by BP are increasing the world's energy supplies, improving recovery rates and getting more for every dollar we invest. LoSal® EOR has immense potential for increasing the amount of oil recovered from the ground. If it can be successfully applied to similar fields around the world it would increase the world’s recoverable oil by billions of barrels."