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Invention prized

March 24, 2000, 08:00 CET

A prestigious award is being presented to two Statoil engineers for discovering a way to prevent drilling mud leaking into the surrounding rock.

Egil Sunde and Hans Konrad Johnsen are due to receive Hart's meritorious engineering award at the Offshore Technology Conference in Houston, Texas, this May.

Their InstanSeal invention comprises a chemical which seals fractures in the rock and prevents mud escaping into sub-surface formations during drilling.

Such loss of fluid can disrupt and delay operations and, in the worst case, lead to an uncontrolled blowout.

A staff engineer in the well technology sector, Mr Sunde explains that InstanSeal is pumped down the well as a liquid.

It flows at high speed out of the bit and into the formation, converting to a hard but flexible compound which fills fractures and keeps the mud in place.

Demand for this product is highest in Canada and the Middle East, Mr Sunde reports. Much of the drilling in these two regions is on land, and loss of mud circulation represents a very common problem in such wells.

"Mud loss isn't a particularly serious issue on Statoil's Norwegian fields at the moment," he says. "We've tested InstanSeal on Gullfaks with good results, but an improved version would be needed before we could draw benefit fully off Norway."

InstanSeal is licensed to France's Schlumberger, which markets it for the moment under the Statoil trademark.