I. PROCEDURE

A. Registration of the Request for Arbitration

1. On 17 May 2006, Occidental Petroleum Corporation (“OPC”) and Occidental Exploration and Production Company (“OEPC”), two U.S. companies, (together the “Claimants”) incorporated in the States of Delaware and California, respectively, filed with the International Centre for Settlement of Investment Disputes (“ICSID” or the “Centre”) a Request for Arbitration under the Convention on the Settlement of Investment Disputes between States and Nationals of Other States (“ICSID Convention’) against the Republic of Ecuador (“Ecuador” or the “Respondent”) and Empresa Estatal Petróleos del Ecuador (“PetroEcuador”).1

2. The parties’ dispute concerns the termination [caducidad] of a 1999 Participation Contract between OEPC and PetroEcuador for the exploration and exploitation of hydrocarbons in Block 15 of the Ecuadorian Amazon region (the “Participation Contract”).

3. The Request for Arbitration invoked Ecuador’s consent to ICSID arbitration contained in the 1993 Treaty Between the United States of America and the Republic of Ecuador Concerning the Encouragement and Protection of Investments (the “BIT”), and PetroEcuador’s consent to ICSID arbitration in the Participation Contract.

4. On 22 May 2006, ICSID acknowledged receipt of the Request for Arbitration and, in accordance with Article 36(1) of the ICSID Convention, transmitted copies of the Request for Arbitration and accompanying documentation to the Republic of Ecuador and PetroEcuador.

5. By letters of 7, 16 and 29 June 2006, ICSID requested additional information from the Claimants. By letters of 13, 23 and 29 June 2006, the Claimants provided information supplementing their Request for Arbitration. Further information was provided by the Claimants by letter of 6 July 2006.