Watching the World Blue barrels and a concrete iceberg

In this column 2 weeks ago I confessed ignorance of how the word barrel had come to be abbreviated "bbl" by the oil industry (OGJ, July 31, p. 38).

Two readers have filled that void in my knowledge.

Olav Nipen, chief geophysicist for international exploration at Norsk Hydro, faxed me this message regarding units of measurement:

"I certainly agree that the SI (Systeme Internationale) system should be more used. In Norway, I think we have made quite some progress in using the metric SI system within the upstream petroleum industry."

Standard storage

Nipen continued, "It was very surprising that you did not know the reason for using bbl' for barrel. I have been told that bbl is an abbreviation of blue barrel, from the blue paint on barrels in the old days."

Brendan Hemming, a London consultant, telephoned to tell me bbl is short for blue barrel, and that blue barrels were originally used by the old Standard Oil Co.

Standard's barrels apparently were made to an exacting specification and to a standard size, and the blue color distinguished them from other companies' barrels, which were not necessarily made to either.

According to my book of quotations, Cicero said, "I am not ashamed to confess that I am ignorant of what I do not know." Sounds like he too found out about blue barrels the embarrassing way.

So thanks to Messrs. Nipen and Hemming for enlightening me.

Thanks are due also to another reader, this time from Wooster, Ohio, for giving me a chance to write once more about a stunning piece of engineering.

Ross Schoolroy, president and owner of oil and gas producer Greenridge Oil Co., wrote a letter to our news editor about a photograph we published of Norway's giant Troll gas platform being towed to the field (OGJ, May 29, p. 17).

Schoolroy's company operates 400 miles west of New Jersey's Atlantic Coast, and you don't find many platforms like Troll in Ohio. He asked for further details about the structure and what kept it from tipping over.

While the picture showed 140 m of the platform's concrete legs above water, it did not show that below the surface the legs extended down to a base of 19 concrete foundation pile cells, open at the bottom.

Below the surface the structure extended 230 m during tow-out to North Sea Block 31/6, where water depth is 300 m. Here the seabed is so soft that operator Norske Shell AS designed the platform with skirt piles that could be sucked 36 m into the seabed to secure it.

Bottom heavy

A Shell official explained that it would have been virtually impossible to topple the platform during the tow because it was like an iceberg, with most of the weight beneath the waves.

The platform weighed 1 million metric tons during tow-out, and 400,000 metric tons was ballast water. This ensured the platform stayed as upright as a weighted fishing float.

"The tow-out was designed to be able to take place in very bad weather if necessary," said the official. "To tip the platform over, we would have needed to hit something on the sea bottom. You can be sure we surveyed the tow route thoroughly first."