Spurred by increased oil demand resulting from Iran's political turmoil, Venezuela has become the sixth oil cartel member to boost its prices above the Organization of Petroleum Exporting Countries' recent two-month-old price rise.

Turning his back on pledges last week that Venezuela would not raise its prices, Energy and Mines Minister Valentin Hernandez yesterday said in Caracas that the world's sixth biggest oil exporter will raise its prices 15 oil exporter will raise its price 15 percent on nearly half the oil it sells beginning March 1.

[In New York, the Associated Press reported that Kuwait told oil companies yesterday it was raising the price of its crude oil by about 9 percent. Kuwait, which produces about 2 million barrels of oil daily, said it was raising the price of crude oil by $1.20 per barrel to $14.55, according to Thomas Walker, a spokesman for Gulf Oil Co., one of Kuwait's largest American customers.]

The Venezuelan oil price increase, which amounts to $2 a barrel, sent tremors through the international oil industry and through the Carter administration where officials are admitting in private that OPEC is almost certain to raise its official price when the 13-member cartel meets in Geneva March 26.

Venezuela's oil pricingmove will add 5 to 6 cents a gallon to fuel oil on the U.S. East Coast, bringing the total price increase since the beginning of the year to 14 cents a gallon. The East Coast imports 70 percent of the industrial fuel oil it burns from Venezuela.

"You are looking at nearly a 50 percent increase in prices since last September," said John Buckley, vice president of Northeast Petroleum Co. of Boston.

Buckley said that some of the Venezuelan price increase also will have an impact on the heating oil market, where prices have risen 16 to 20 cents a gallon on the spot market since the beginning of the heating oil season.

Venezuela's pricing announcement, another oilman said, "simply follows the spot market prices penny for penny."

According to one senior administration official, "The Venezuelans' price increase caught the Energy and State departments totally off guard."

Other OPEC members who have raised prices on all or some of their oil sales include Saudi Arabia, Abu Dhabi, Qatar, Kuwait, Libya and Iraq.

The Venezuelan action surprised oilmen and administration officials, however, because Venezuela's production of more than 2.2 million barrels a day consists of heavier grade, less desirable, crude oils. The Saudis and others have to varying degrees raised prices $1 to $2 a barrel on so-called "premium" grades of oil that are low in sulfur and more economic to refine into gasoline.

Adding still another measure of uncertainty to already taut oil markets, the Saudi oil minister, Sheik Ahmed Zaki Yamani, confirmed growing fears within the administration that OPEC will increase prices in March.

"Some member countries feel that the oil companies are really making a windfall profit -- that they have to take part of that profit back to their treasuries," Yamani told a London conference on world energy economics yesterday.

Yamani went on to say, "So I do expect some sort of a temporary increase, small in size, by some member countries." The western-educated oil minister, however, did say that he expected the next price increase to be "moderate" and that it "will never be incorporated in the price structure as it was decided by OPEC in Abu Dhabi last December."

Hernandez's shock announcement came after a visit to the Perisan Gulf where he consulted with the Saudis, and informed sources suggested that Saudi Arabia did little to dissuade the Venezuelans from acting.

More importantly, however, analysts point to the intense consultation between Yamani and Abu Dhabi's respected oil minister, Sheik Mana Saeed O'Taiba, two weeks ago in Riyadh. Abu Dhabi raised its prices by more than $1-a-barrel after the meeting. Abu Dhabi had previously joined the Saudis in arguing for moderate price increase in OPEC circles, closely matching its oil price strategy with that of Saudi Arabia.

"Abu Dhabi would never act without Riyadh," said one administration official.

Amid signs of the Saudis' willingness to allow other cartel members to push for higher oil prices, and indications that relations between Riyadh and Washington are becoming more strained, administration oil analysts privately say that the Saudis will likely not be arguing vigorously against a new OPEC price rise.