On March 14, 2005, PNOC EC, CNOOC and Vietnam Oil and Gas Corporation (PETROVIETNAM) signed a “Tripartite Agreement for Joint Marine Seismic Undertaking in the Agreement Area in the South China Sea”.

The Agreement provides for the joint acquisition of seismic data in order to assess the petroleum resource potential of the Agreement Area. The first phase of the seismic survey commenced in September 1 and ended on November 16, 2005 with a total coverage of 11,021.65 line kilometers. The Chinese seismic vessel M/V Nan Hai 502 of China Oilfield Services Ltd. (COSL) was contracted to conduct the survey. A representative each from PNOC EC, CNOOC and PetroVietnam were onboard the vessel during the entire period of seismic acquisition. The data gathered from the survey, as well as additional data sourced from PNOC and CNOOC were then processed in Vietnam. Interpretation immediately followed in Manila with PNOC EC as operator of the activity. Second phase of the 2D seismic acquisition campaign began in October 2007 and is expected to be completed in January 2008 with target coverage of 11,827.47 line kilometers.

The Philippine government has been strongly pushing for the realization of the agreement in the interest of building and maintaining peace, stability, security and prosperity in the contested areas in the South China Sea. The Tripartite Agreement, which covers an area of 142,886 square kilometers west of Palawan, is considered a big step towards transforming a previous area of conflict into an area for possible cooperation and mutual benefit. The agreement is however designed to be scientific in nature and does not affect territorial claims of the respective countries of the area.