At a time when hydrocarbon profits are running out of gas, Primark Corp. has moved to Washington and begun diversifying into financial and satellite communications businesses, hoping to take the company the extra mile.

In May, Primark, the holding company for Michigan Consolidated Gas, a gas utility business serving 1 million customers, moved its headquarters and 25 top executives from Detroit for two reasons: to be closer to the policy makers who affect its businesses and to concentrate on new acquisitions.

Washington "is the seat of government, and a great deal goes on here that does influence businesses, the natural gas and finance business and communications business -- about every one you can think of," said company President Robert W. Stewart.

"Here I get a rundown while I'm shaving of what committees are meeting, and driving home I get a rundown of exactly what happened today," said John J. Lewis, director of investor relations for the company.

Primark executives, who previously had run the utility and the holding company, left behind a separate new management and 4,100 employes at Michigan Consolidated Gas when they moved to Washington.

The company has chosen to diversify into areas unrelated to the utility business partly because of a slump in the natural gas industry and partly because of the dim view utility regulators take of financial relationships that involve utilities in businesses that are difficult to distinguish from the utility's operations.

"We do not see really good growth opportunities in the gas industry," said Stewart. "We've elected to diversify into unrelated activities because of our feeling that if we get into gas-related matters, it raises questions with Michigan Consolidated's state regulators." Regulators monitor utilities to make sure that none of the guaranteed rate of return that a utility receives goes to nonutility businesses. When a utility is in utility-related businesses, the line blurs.

So far, the company has made bold diversification moves by acquiring or starting up financial services firms and a communications business, called Hospital Satellite Network. The network is designed to save money for the health care industry by beaming educational programming directly to hospitals.

"A relatively small percentage of utility companies are diversifying out of the energy business, so in that regard Primark is unusual," said Michael I. German, vice president of the American Gas Association. "Most diversification has been functionally related."

Instead, German said, Primark is transferring skills that are essentially service-oriented into other service businesses it has acquired.

"Our strategy in diversification was we did not want to get involved in heavy manufacturing that required a lot of capital," Lewis said.

"Growth was in the service sectors. . . . The gas business is a service business, so we really have experience."

Whether the company will succeed in its ventures, some of which are not yet turning a profit, remains to be seen, analysts say. "Because they are entering untested waters for gas companies, you have to believe in the management of the company," said Foster Corwith, an analyst with Dean Witter Reynolds Inc.

"From what I've seen, the management is pretty sharp, and I have confidence they will be able to achieve their goals, which is one third of all earnings from nonutility businesses by 1988."

Primark, nestled in McLean, became the fifth-largest company in the Washington area by virtue of moving here. It ranks just behind Giant Food Inc. and in front of Gannett Co. Inc., with revenue of slightly over $2 billion and profits of nearly $50 million in 1984. Since 1981, when the company was spun off from American Natural Resources, a natural gas production, transmission and utility business, Primark's profits have grown from $16.5 million on revenue of $1.7 billion to $49.5 million on revenue of $2 billion. Now Primark is looking at possible new acquisitions.

"We are still looking in the health care field and are looking to expand our mortgage banking business," said company president Stewart. Primark is also actively investigating two companies. "One is in aviation services, the other is in electronics and aerospace," he said. Stewart would not specify which companies or if they are in the Washington area. Primark has about $80 million to $200 million to spend on acquisitions, he said.

Formed in 1981, Primark was spun off from American Natural Resources because the parent company "was having difficulty making money with Michigan Consolidated," Lewissaid. American Natural Resources formed Primark as a subsidiary, transferred Michigan Consolidated stock to Primark, and then spun off Primark.

"Our first job was to return the company to a financial position it should have been in all along -- we've done that," Lewis said. "Then, really, the natural gas utility business is not a growth business, and we wanted to continue to grow as a corporation."

Primark first diversified into related areas by forming Primark Leasing Corp., which leases gas storage facilities. It then formed Primark Financial Services Inc., a financial services and insurance business consisting of Westmark Savings Bank, a small California savings and loan, Westmark Mortgage Co. and Primark Insurance Cos.

More recently, it purchased Hospital Satellite Network (HSN) and its subsidiary, Hospital Communications Inc. Formed to provide communications consulting services to the health care industry, Hospital Communications is a holding company for a smaller company, Comtel Systems, which provides telephone service to hospital patients.

HSN recently signed a contract with Voluntary Hospitals of America Inc., the largest hospital group in the country. HSN will provide its services at a discount to the 440 member hospitals that make up the organization, representing more than 8 percent of hospital beds in the United States.

Last year, Michigan Consolidated made about $45 million in net income, Primark's leasing business made about $8 million and HSN, based in Los Angeles and for which Primark paid more than $5.5 million, lost $3.6 million in its first year of operation. Primark's start-up financial services businesses also lost about $1.2 million, Lewis said.

The company expects its financial services to make "a couple million in profits" this year and HSN to make "modest profits" in 1986, with combined profits for both of $3 million to $5 million by 1987, Stewart said. Stewart played down previous statements about nonutility earnings accounting for a third of the company's profits by the end of the decade.

But HSN is the apple of Primark's eye and is a unique venture in the health care field that might make very good money for Primark, according to the company's officials. "We can save hospitals money," Lewis said. "Plus the fact that it is a service that is a necessity because there was no national means of communicating medical research."

The network provides teleconferencing between hospitals and beams via satellite medical programming put together by medical experts and professional producers. "Hospitals spend 4.5 to 6.5 percent of their total budget for hospital education and training," said HSN President Peter Feeney. "If a 300-bed hospital has a $100 million budget, $5 million could go toward education, and we could maybe shave off 10 or 20 percent."

The subsidiary, which has 50 employes, has 323 subscribers and is negotiating with hundreds more, he said. "Hospitals need to cut costs and at the same time improve patient care, and if we could eliminate the need for travel by bringing information to them, it's an idea that just makes sense," he said.

So far most of Primark's ideas make sense, according to several analysts.

"The prospects for growth in those businesses are far above average," said Robert Dunlap, an analyst with Brown Bros. Harriman & Co.