On August 18, 1997, Petroleum Contract between CNPC and Enron Oil & Gas China Ltd. for Petroleum Development and Production of the Chuanzhong Block,Sichuan Basin, the people's republic of china has been signed and officially implemented on October 1, 1997. The contract period is 30 years. The present contractor is EOG Company. The project experienced four phases: pilot test phase, appraisal phase, develop-ment phase and the commercial production phase. Currently，the project is under the last phase.