Among the "Seven Sisters" of world oil, the Royal Dutch/Shell Group of Companies is probably the most decentralized, the most international - both in management and scope of operations - and the most complex in organizaiton.

The group is actually a British-Dutch holding company with 60 percent owned by Royal Dutch Petroleum Co. and 40 percent by Shell Transport and Trading Co., the two companies that merged in 1907.

The stocks of both companies continue to trade independently, as does the stock of Shell Oil Co., the 69 percent owned by U.S. subsidiary which by itself ranks as the 13th largest U.S. industrial corporation, based on 1977 sales of over 10 billion.

The company is run by a group of eight managing directors - C.C. Pocock is the current chairman - and it has dual headquarters in London and the Hague. Continuing the traditions of its origins, the company's financial and trading activities remain centered in London and the technical and exploratory operations are mainly run from the Netherlands.

Shell Oil U.S.A. is pretty much left to run its own, and is the largest gasoline marketer in the country, by some measures, and ranks fourth in domestic crude oil and natural gas liquids production. Dividends from Shell Oil are reinvested by a group back into Shell Oil stock to maintain the 69 percent equity position in the company.

"It can be described as a series of dukedoms rather than a centrally run operation," commented Joseph Tovey, an investment banker specializing in the oil companies.

Second in size among the oil companies to Exxon, outside the U.S. Royal Dutch-Shell is by far the largest corporation in the world. Overall revenues last year totaled $45 billion.

The group's profits, however, have to be scrutinized cautiously since, though it is a foreign company, it must adhere to U.S. accounting standards, including the controversial one on foreign currency fluctuations, because its various equities are traded on U.S. exchanges. This had produced some phenomenal swings.

Last year Royal Dutch/Shell exceeded Exxon in earnings for the first time, though this was wholly due to the currency impacts.

In 1978 the swing has been the other way, with a vengeance. While underlying business for the group improved in the first quarter, net income of $532 million was reduced to only $11 million by the currency translation rules. In the second quarter the effect went the other way, with net income of $524 million being boosted to $725 million by currency adjustments.

The company is distinguished by also being the biggest chemical producer among the oil companies. Total chemical sales last year came to 4.6 billion. But production was concentrated in the high volume commodity chemicals that are currently in great surplus so the profitability has been slim.

The events of the past five years since the Arab oil embargo have not radically changed the direction of Royal Dutch/Shell, according to the company.

"We have not suddenly taken off into new exploration schemes or diversification because of what happened five years ago," the company said. "What is different is that we are obviously very interested in finding oil in non-OPEC countries."

But he added that "there is an aphorism in the oil business that Shell is able to sell the stuff but never able to find it. We are crude-short company. And we seem to have terrible luck in exploration."

Abroad Shell is involved in a number of major joint ventures with Exxon. In the North Sea, for example, the two companies poured millions of dollars into the what was known as the "Goldenblock" area. But they discovered no oil while companies around them were hitting what turned out to be some of the richest fields in the area.

Shell now gets about 60,000 barrels from the North Sea and hopes to be getting 400,000 barrels by the 1980s.

What it lacks in exploration luck, it makes up in trading savvy and has managed to secure enough oil for its refineries either in the spot market or in long-term arrangement with other producers. Shell has concluded such a long-term deal with Saudi Arabia through the Aramco consortum.

The company's world-famous "Shell" symbol relates directly to its origins. In 1833, a London shopkeeper, Markus Samuels began selling items he purchased from sailers. Shells were particularly popular. He tried to get regular shipments of the Shells from the Orient and this developed into an import-export business.