AUTHORS Franc ¸ ois Fournier  Formation de Recherche en Evolution - Centre National de la Recherche Scientifique 2761, Laboratoire de Ge ´ologie des Syste `mes Carbonate ´s, Case 67, Universite ´ de Provence, 3, Place Victor Hugo, F-13331 Marseille Cedex 03, France; Francois.Fournier@up.univ-mrs.fr Franc ¸ois Fournier received his M.Sc. degrees from the Nancy School of Mines (France) and from the Institut Franc ¸ais du Petrole and a Ph.D. in car- bonate sedimentology from the University of Provence in Marseilles (France). After a short ex- perience in oil companies as an exploration ge- ologist in France and Angola, he joined the Geology of Carbonate Systems Laboratory (Marseilles, France) as lecturer in 2005. His research focuses on the relationship between sedimentology, diagene- sis, and seismic reflections in carbonate reservoirs. Jean Borgomano  Formation de Recherche en Evolution - Centre National de la Recherche Scientifique 2761, Laboratoire de Ge ´ologie des Syste `mes Carbonate ´s, Case 67, Universite ´ de Provence, 3, Place Victor Hugo, F-13331 Marseille Cedex 03, France Jean Borgomano obtained a Ph.D. in carbonate geology in 1987 at the University of Provence in Marseilles (France). In 1988 – 2003, he worked at Shell as senior carbonate geologist in various exploration and production Shell companies. He is currently a professor at the University of Provence and the director of the Geology of Carbonate Systems Laboratory. His research fo- cuses on the geological characterization and nu- merical modeling of carbonate reservoir archi- tecture and properties. ACKNOWLEDGEMENTS This work was funded by Shell Philippines Ex- ploration B.V. We gratefully acknowledge Shell, Chevron-Texaco, and the Philippine National Oil Company for the access to data and the per- mission to publish this work. This paper signifi- cantly benefited from stimulating discussions with many Shell staffs in research and opera- tional business units. We thank M. Joachimski (Erlangen University) for carbon and oxygen iso- tope analyses and the Laboratory of Isotope Geochemistry at the Vrije Universiteit (Amster- dam) for Sr isotope ratio measurements. Re- viewers Richard Worden, Art Saller, and David Eby gave constructive suggestions for the im- provement of the manuscript. Geological significance of seismic reflections and imaging of the reservoir architecture in the Malampaya gas field (Philippines) Franc ¸ois Fournier and Jean Borgomano ABSTRACT The integration of petrographic analyses of cores and thin sections, petrophysical measurements, and well logs demonstrates that varia- tions in acoustic impedance in the Malampaya buildup (upper Eo- cene to lower Miocene, offshore northwest Palawan) are related to vertical changes in porosity and pore type, which are dominantly controlled by diagenetic processes. The Nido Limestone was subdi- vided into 10–50-m (30–150-ft)-thick units characterized by spe- cific diagenetic patterns and petrophysical properties (diagenetic units). The alternation between tight and porous diagenetic units is mainly controlled by meteoric diagenesis (leaching and pedogen- esis) and by late-burial cementation and leaching. Well-to-seismic ties show that the main seismic reflectors within the buildup in- terior reflect the boundaries between diagenetic units. Most of the negative amplitude reflectors are related to unconformities, where- as positive amplitude reflectors have a more questionable chrono- stratigraphic value and may represent the bases of cemented lenses that can crosscut time lines. Comparison with other southeast Asian Tertiary buildups indicates different origins of seismic reflections related to distinct patterns of diagenetic evolution. The identification of such seismodiagenetic units and of their controlling factors is of paramount importance for the architecture and the petrophysical characterization of carbonate reservoirs. INTRODUCTION Seismic reflection imaging has become an unparalleled geophysical method to image subsurface architecture of carbonate systems (e.g., Belopolsky and Droxler, 2004; Eberli et al., 2004) and to assess the AAPG Bulletin, v. 91, no. 2 (February 2007), pp. 235–258 235 Copyright #2007. The American Association of Petroleum Geologists. All rights reserved. Manuscript received April 26, 2006; provisional acceptance July 6, 2006; revised manuscript received August 21, 2006; final acceptance October 16, 2006. DOI:10.1306/10160606043