Kazakhstan Oil Production: The former Soviet republic of Kazakhstan will produce as much as 29 million tons of crude oil in 1993 and may double that output within two years, the republic's president, Nursultan A. Nazarbayev, told journalists in Switzerland. He also said Chevron Corp. is on schedule to take over production at the Tegiz oil fields by April. Chevron, which has spent $25 million during the past four years negotiating the joint venture, had expected to start full operations at the 25 million-barrel field on Jan. 1. Its plans were delayed by technical and legal snags. The Tegiz fields, one of the world's largest potential sources of crude, are likely to produce about 3 million tons of oil for international markets in the first year, Nazarbayev said. The 40-year project, expected to cost about $10 billion, is the largest single Western investment in the former Soviet Union.