LATIN OIL PRODUCERS TO MEET IN CARACAS Five regional oil producing nations will gather in Caracas tommorrow for a two-day meeting expected to center on ways to combat proposals for a U.S. tax on imported petroleum, the Venezuela's ministry of energy and mines said. Oil ministers from Mexico, Trinidad and Tobago, Ecuador and Venezuela will be on hand for the fifth meeting of the informal group of Latin American and Caribbean Petroleum Exporters, formed in 1983, it said. Colombia will also attend for the first time, as an observer nation, the ministry said. Energy and Mines Minister Arturo Hernandez Grisanti said the conference has no set agenda but one entire session Friday will be devoted to proposals for a tax on imported oil. Two of the group's members, Venezuela and Mexico, are second and third largest foreign suppliers of oil to the United States, respectively, following Canada. Venezuela, concerned about the effect such a tax would have on its exports, undertook a diplomatic push to coordinate strategy against such measures. In February, Canadian Energy Minister Marcel Masse was invited to Caracas for talks with Hernandez on proposals for an oil import tax.