DHAHRAN, SAUDI ARABIA -- The wellhead, topped by the array of heavy steel valves and flanged pipes known in the industry as a "Christmas Tree," has a brick walkway and small garden surrounding it, a postage-stamp oasis in the dry, midday heat of eastern Saudi Arabia.

Dammam No. 7, spudded in by Standard Oil of California on Dec. 7, 1936, struck oil at 1,441 meters on March 3, 1938. "In drilling this well the Arab Zone was discovered," reads the modest inscription on a nearby plaque. Dammam No. 7 "made possible the development of oil in Saudi Arabia."

Today Dammam No. 7 is the patriarch well of Saudi Aramco, the world's largest oil company, developer of the world's biggest oil field and custodian of 25 percent of the world's proven petroleum reserves -- reckoned at 270 billion barrels at the end of this year, up about 15 billion from 1989.

If the United States and its allies in Operation Desert Shield fight a war against Iraq, it will take place on top of the Earth's biggest petroleum deposit.

For most Saudis, keeping the "Arabian Zone" out of the hands of Iraqi President Saddam Hussein is reason enough to fight. U.S. forces have deployed accordingly: missiles, tanks, artillery and men are spread about northeastern Saudi Arabia guarding ports, refineries, wells and airports. Last year Saudi Aramco pumped 5 million barrels of oil each day. The United States bought 25 percent of it.

Understanding the stakes implied by this arithmetic, most of Saudi Aramco's 11,500 foreign employees, including 2,500 Americans, have decided they have more protection in northeastern Saudi Arabia than they would in most places in the world.

"We're not nervous," said Paula Reimer, 40, a preschool teacher from Boston married to a Saudi Aramco systems analyst. "We're pretty normal. We all have kids and jobs, and we all have dogs. If we're weird, we're weird together."

Saudi Aramco, today a fully owned Saudi Arabian state enterprise, has its headquarters in Dhahran, which did not exist until oil was discovered. Dammam No. 7 sits on the edge of town, its location marked the wildcatter way: an empty oil drum nailed to a lightpost.

The Saudi Aramco compound, reminiscent of the former Panama Canal Zone, is a hybrid enclave in a strange setting -- an expatriate slice of English-speaking, baseball-playing, small-town America tucked away in the Saudi desert.

The compound has gardens and lawns, pleasant one- and two-story wood and stucco houses, schools, ballfields, swimming pools, tennis courts, a movie theater, a grocery store and a cafeteria. There is an aviation club, a Little League and golf tournaments every Thursday. There are streets named Acacia, Lilac and Cactus, and a country club called Rolling Hills.

Saudi Aramco pays its employees well and treats them with dignity. When the Persian Gulf crisis began, the company proclaimed an across-the-board 15 percent raise -- hazardous duty pay. Some of the foreigners who work here today are the grandchildren of Aramco employees. Some of today's employees have sons serving in Desert Shield.

"I don't feel living over here we've missed anything," said Jess Arceneaux, principal of Saudi Aramco's junior high school and a 20-year "Aramcon." "It's been a wonderful experience, and I'd advise anyone to do it."

The Aramcons -- foreigners and Saudis together -- have made a humanitarian project out of the soldiers assigned to Desert Shield. Every night under the Host-a-Soldier program, servicemen and women come to the compound for dinner, showers, laundry and phones. On Thursdays volunteers called Desert Dogs take sodas and hamburgers out to the soldiers. A Hospital Support Group does volunteer work at the Red Cross and military field hospitals.

Meanwhile, Saudi Aramco, which has nothing to do with the soldier programs of its employees, has upped petroleum production from 5.3 million barrels per day on Aug. 1, the day before Iraq's invasion of Kuwait, to 8 million barrels per day. The increased Saudi production has helped make up the shortfall caused by the trade embargo on Iraq and Iraqi-occupied Kuwait.

Saudi Aramco had its roots in a contract signed in 1933 between Standard Oil of California (Chevron today) and the Saudi government. In 1936, the Texas Co. (Texaco) bought half of what was then the California Arabian Standard Oil Co. In 1944, the firm renamed itself the Arabian American Oil Co., or Aramco. By 1950, Standard Oil of New Jersey (now Exxon) and Socony Vacuum (Mobil) also had bought shares.

With the big four of the U.S. oil industry controlling Aramco, production grew dramatically after World War II: from 58,386 barrels per day in 1945, to 546,703 barrels per day in 1950, to 1.2 million barrels per day in 1960, to 3.5 million barrels per day in 1970.

In the late 1940s, Aramco geologists opened the Ghawar oil field, a vast stretch of desert extending 160 miles southwest from Dhahran. At 5,000 square miles, it is the world's biggest known petroleum deposit. Later, Aramco sunk its first offshore well in the Safaniya field, in the Persian Gulf near the northeastern border. It is now the world's biggest offshore oil deposit.

In 1973, the government began the "Saudi-ization" of Aramco, buying 25 percent of the company from its four American owners. By 1980, the changeover was complete. That same year, oil production reached a record average of 9.63 million barrels per day. In 1988, King Fahd issued a decree changing the company's name to Saudi Aramco.

During the years of fastest expansion, in the late 1970s and early '80s, company employment swelled to about 60,000, and the American community stood at around 24,000.

"Everybody was in the same boat together," said Chris Haltiner, 43, an Englishwoman who came to Saudi Arabia in 1979 with her husband, a Canadian geophysicist. "It was the beginning of the big expansion, and there were so many new people. It's not the same now."

Today, Saudi Aramco has about 45,000 employees, of whom 32,000 are Saudis. In all, the company has citizens of 50 nations on its payroll.

Most of the Aramcons answered ads or responded to recruiters. Jess Arceneaux, bored in Texas working as a math teacher, saw a vaguely worded come-on in an educational journal. Haltiner and her husband were "not living high on the hog" in Calgary when Aramco recruiters came knocking.

Gerry Gabuyo was living in Manila when he saw an employment agency pitching jobs for short-order cooks in Saudi Arabia. Eight years later, Gabuyo, 41, manages the Rolling Hills Country Club and pro shop. His wife and children are still in the Philippines, but he said that if he can get a multiple-entry visa to the United States, he hopes a club member can sponsor him for American citizenship. Saudi Aramco, he said, "is the best."

Most Aramcons -- Saudi or foreign -- work on company contracts and live on the compound. Junior employees have apartments. Senior people have neat, comfortable houses at nominal rent.

Foreign children have free schooling in English on the compound through ninth grade. After that, they must go overseas to boarding school, but Saudi Aramco picks up 80 percent of the tab and pays for three round trips home for each child.

The company grants regular raises, but employees are beginning to grouse that they are not as big nor as frequent as a few years ago.

Many Aramcons also have trouble with the restrictions of living in a religiously conservative society. They find oppressive the Saudi prohibitions on alcohol and the practice of religions other than Islam. And while women can drive on the Saudi Aramco compound, they need male chauffeurs to go shopping in nearby towns.

Despite the total absence of panic at the compound, Arceneaux says he has lost about 37 percent of his students since the gulf crisis began in August. Diplomatic sources say about 70 Aramcons have resigned in the same period.

"It's mostly people with younger kids," said Paula Reimer. "But if you're in your middle or late forties, what are your job prospects in the States? We have a lot invested in this company."

Arceneaux long ago made peace with his environment. He plays golf at Rolling Hills, where the "greens" are heavy dirt and the "fairways" are sand blackened with oil so it doesn't blow away. If you can keep your shots on the fairway, Arceneaux said, you can use a white ball. Otherwise, he recommends orange, Day-Glo pink or lime green.