The deep-water Wilcox trend covers more than 34,000 mi 2 , extending across the Alaminos Canyon, Keathley Canyon, and Walker Ridge protraction areas, plus parts of adjacent protraction areas and Mexican territorial waters. Discoveries are in turbidite sands that have been deposited in lower slope channels and ponded fans to regionally extensive basin floor fan systems. Primary trap styles are compressional Louann saltcored symmetrical box folds, symmetrical salt pillows, and asymmetrical salt cored thrust anticlines. More than 20 wildcat wells have been drilled in the Wilcox Trend. Recoverable reserves for each of the 12 announced discoveries range from 40 to 500 million barrels of oil (MMBO). Ultimately, the Wilcox trend has the potential for recovering 3 to 15 billion barrels of oil reserves (BBO) from these discoveries and additional untested structures. Many technical issues need to be resolved to move the billions of barrels of resources trapped in deep-water Wilcox structures to recoverable economic reserves. Exploration challenges include well depths up to 35,000 feet subsea, water depths ranging from 4,000 to 10,000 feet, and salt canopies from 7,000 to more than 20,000 feet thick. Allochthonous salt covers 90% of the trend, complicating regional reconstructions and resolution of individual structures. Appraisal challenges include: delineating and modeling reservoir quality,

Overview of Malampaya Field: The Malampaya-Camago Gas-Condensate field is a Tertiary Carbonate build-up that is situated offshore to the northwest of Palawan Island (Philippines) below 800–1200m of water. It was discovered by Occidental in 1989 (Camago-1) and is operated by Shell (45%) with Chevron (45%) and the Philippines National Oil Company (10%) as equity partners. The field has been supplying gas from five subsea production wells since late 2001 to three Gas to Power plants on Luzon Island. Available subsurface data include a 2001 high resolution 3D seismic survey, five production wells and six exploration/appraisal wells with wireline and borehole image data, including spot core in selected wells, pressure and well test data. A schematic of the Malampaya gas to power project is shown below. Overview of Experimental Design (ED) Methodology An extensive reservoir characterisation study was carried out by Chevron on a non-operated asset in 2004 to determine gas-in-place and reserves distributions. This paper outlines the Experimental Design (ED) methodology used in the study which using material balance models integrated the static and dynamic reservoir uncertainties with the excellent reservoir pressure history data that exists for the field. The methodology incorporated a unique and "state-of-the-art" method for screening over 20,000 reservoir realisations to allow only those realisations that showed a close match to the pressure history to be included in the generation of GIIP and reserves distributions. This aspect of the ED methodology proved to be very powerful in generating reserves distributions in a "hands-off" approach without the requirement for traditional manual adjustment of reservoir parameters to get a "history match".

The wettability of a petroleum reservoir governs the location of fluids within its pore space and hence the movement of fluids through it during production. Properties that may be affected by wettability include resistivity, capillary pressure, relative permeability and rock strength as well as behaviour during waterflood and enhanced oil recovery. Generally every reservoir is initially assumed to be water wet. When production problems arise, the wettability of a reservoir will only be questioned when all other possibilities have been accounted for. By correctly determining the wettability of a reservoir more accurate models can be provided for reservoir simulation, which in turn will improve the prediction of future field performance.Many methods of varying difficulty and accuracy can be used to measure wettability. However, they can only be as good as the quality of the fluid samples used. It is important to understand that reliable results are only obtained when sample contamination is minimised and experimental control is maximised. Some wettability experiments can be carried out at reservoir conditions, which may be more representative, but also more susceptible to contamination.In an oil reservoir either oil or brine can be the most wetting phase and gas is normally the least wetting phase. From a thorough investigation of downhole logs and production data it may be possible to identify wetting anomalies. Examining formation pressure data is the most recent method proposed for determining wettability.

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