Integrate Seismic to Constrain Uncertainties in Rock Property Distribution: An Example from the Far East

Wenche H. Asyee¹, Georg Warrlich², Conxita Taberner¹, Maria Boya-Ferrero², and Ben Stephenson^3
1 Shell International E&P, Rijswijk, Netherlands
² PDO, Muscat, Oman
³ Shell Canada, Calgary, AB

The Malampaya gas field located offshore Philippines in the South China Sea has always been considered to be one of the examples of a complex mid Tertiary isolated platform. The structural history during the platform growth and resulting facies distribution have always been recognized as the main factors controlling the diagenetic processes during the evolution of the field and the resulting property distribution.

Since the discovery of this deepwater (+ 850 meters) gas field in 1991 numerous studies have been carried out to describe and analyze the geological history of the build-up and the distribution of rock properties. From early 2003 until early 2005 the Shell Carbonate Team in Rijswijk (NL) carried out a study integrating all available old and new data. Apart from an additional diagenesis study and structural analysis of the data also the new high-resolution 3D seismic survey shot by PGS in 2002 was analyzed. This survey was reprocessed by Shell and optimized by Chevron to enhance resolution and decrease noise and artifacts (sea bottom multiples) before stacking.

The attribute analysis of the impedance cube calculated from the high resolution seismic gave new insights in the property distribution of the field. The integration of the acoustic impedance volume with the new and existing geological studies allowed the study team to decrease the uncertainty in the rock property distributions and a renewed understanding of the geological history of the field beyond the time of deposition.

The authors would like to thank PNOC and CHEVRON for their support.