NEW YORK (AP) _ Oil prices dipped in light trading Monday in the absence of any increased tensions in the Persian Gulf.

Analysts said traders continued to liquidate long positions as prices tumbled from their peaks reached earlier in the month.

''It is almost entirely a long liquidating market,'' said Michael Himmel, an analyst for Shearson Lehman Brothers Inc. in New York.

Traders who had bought contracts in anticipation of future oil price increases have been selling off since late last week to take advantage of prices that had been inflated by the shipping crisis in the Persian Gulf.

On the New York Mercantile Exchange, contracts for September delivery of West Texas Intermediate, the benchmark U.S. crude oil, settled at $20.49 a barrel Monday, down 8 cents from Friday's close. A barrel is the equivalent of 42 gallons.

The United States began escorting Kuwaiti oil tankers through the troubled gulf last week to shield them from conflict in the ongoing Iran-Iraq war. The tankers also have been re-registered as U.S. vessels for protection.

Although one tanker, the Bridgeton, hit a mine Friday while bound for Kuwait, the incident has not been viewed as serious enough to spark a jump in futures prices.

In fact, Himmel said, the market has been lulled since late last week by the ''threat of peace'' in the region.

Himmel said the price, which had broken through the $22-a-barrel mark earlier this month, was now nearing ''the theoretical fair market value.''

The September contract traded between $20.45 and $20.65 a barrel during Monday's session. Prices fell near the end of the day as cautious traders moved to the sidelines, analysts said.

Meanwhile in the gulf, U.S. Coast Guard officers were trying to determine whether the reflagged tanker Bridgeton can carry a partial cargo under U.S. Navy escort this week despite the damage caused by the mine.

Shipping sources in Kuwait said the government-owned Kuwait Oil Tanker Co. hopes to send the Bridgeton and the Gas Prince south this week on the 500-mile voyage to the Strait of Hormuz.

The two vessels are the first of 11 Kuwaiti tankers to be re-registered as U.S. vessels.

Although Defense Secretary Caspar Weinberger said on ABC television Sunday that the U.S. ability to deal with mines in the gulf ''can be increased and will be increased,'' the threat of heightened activity did not seem to concern futures traders.

Analysts said traders were more concerned about unloading contracts while they could still realize some profits from the recent price runup.

Also, Department of Energy figures showed Monday that U.S. oil companies have allowed their crude oil inventories to shrink to their lowest level in nearly two years. Crude stocks in mid-July totaled 320.1 million barrels, the lowest since 313.7 million recorded at the end of October 1985.

Analysts said the dwindling inventories supported the idea that the recent price spike was mostly a psychological phenomenon. They said companies would not be cutting back inventories if the lofty price levels reached this month had been supported by the fundamentals of supply and demand.