Faced with the prospect of an oil price-cutting scramble, representatives of leading oil producers convened here today in an effort to reach a tentative accord on pricing and production that would serve as a global guideline for the slumping market.

Envoys from eight members of the Organization of Petroleum Exporting Countries--representing the views of every key member except Iran--recessed after more than five hours and will meet again Friday in what is planned to be a two-day session.

"We hope there will be an agreement," said Venezuelan Oil Minister Humberto Calderon Berti. "There is still more work to do."

Analysts say that the OPEC majority, led by Saudi Arabia, hopes to set a reference price no higher than $30 a barrel--$4 below the current level--and agree on a production quota no greater than 17.5 million barrels a day. OPEC recently has been producing less than 14 million barrels a day, down sharply from the 30 million it was producing four years ago.

If a preliminary agreement can be reached here, OPEC plans a full emergency session of the 13-member group, probably in Lausanne, Switzerland, on Monday.

But an eventual accord is still far from assured. Despite intensive consultations, similar OPEC efforts recently to stabilize the market have failed, largely because a world oil glut combined with economic and political factors in member countries has led to widespread undercutting. Last month, Nigeria became the first OPEC nation to officially drop its price, lowering it by $5.50 to bring it under those of non-OPEC producers, such as Britain, with which it directly competes.

Britain, and then Norway, lowered the price of North Sea crude when major customers refused to pay the previous higher rate. These moves were seen as the forerunner of still greater reductions as buyers take advantage of the glut while OPEC influence and solidarity declines.

The choice of London for the talks is apparently part of a Saudi-directed OPEC effort to enlist the cooperation of such key independents as Britain and Mexico in a realignment of the pricing and output structure that would forestall a complete collapse of the fixed-price market.

A Mexican envoy was here today as an "observer" but did not participate in the OPEC deliberations, the embassy said.

British Energy Minister Nigel Lawson met this morning with Calderon and tonight with Mana Said Oteiba, oil minister of the United Arab Emirates, a spokesman said. But British officials have said there is no likelihood of Prime Minister Margaret Thatcher's government or the state-owned British National Oil Corp. joining with OPEC in a bid to control world prices.

"It would not be practicable" for British Oil to set its prices, the government said in a parliamentary statement today, "in reference to the interests" of any group of countries--clearly meant to be OPEC. Britain believes that market forces alone should determine oil prices, sources said.

Britain's deputy energy minister, Hamish Gray, also told Parliament that the government would not impose production cuts at least until the end of 1984, Reuter reported.

Although Britain is now the world's fifth largest oil producer, "we are not a petro-economy," one analyst said. "We are a western manufacturing economy and we would gain more than we lose from a fall in oil prices."

Despite Britain's resistance to any arrangement with OPEC, the government is known to prefer an orderly reduction in prices to minimize the shock that a steep fall in oil revenues would have on the world economy. But for now, that is a risk the Thatcher government is prepared to take rather than joining forces with OPEC.

Besides the oil ministers of Saudi Arabia, Venezuela and the United Arab Emirates, those attending represented Nigeria, Algeria, Libya, Indonesia and Kuwait. Of those not present--Iran, Iraq, Qatar, Gabon and Equador--Iran is vehemently opposed to price reductions, favoring instead lower production quotas.

"Again there is a plot in OPEC to inflict economic blows on Iran and other deprived countries," Iranian officials were quoted as saying today.