Formation evaluation quality and cost efficiency are crucial in ultra-deepwater reservoir evaluation. Reservoir properties such as fluid composition, formation pressure, and sand producibility are critical in the exploration and appraisal phases of the well life and represent a key input to comprehensive production and reservoir engineering studies in the development phase. In addition, contaminants measurement including hydrogen sulfide (H2S), carbon dioxide (CO2), and mercury are important to address challenges in the planning and utilization of equipment and production facilities.

This work is based on recent experience in South-East Asia that demonstrate prudent operatorship in maximizing value of information (VOI) from exploration drilling and evaluation. These formation testing is conducted to address the inherent uncertainty in reservoir characterization; particularly reservoir connectivity, producibility and presence of fluid's contaminants. Integrated measurements such as core data, log analysis, image logs, pressure data and fluid sampling were utilized to better characterized the reservoirs. Advanced sampling method was conducted to evaluate presence of contaminants including H2S, CO2, and mercury in the reservoir. Onsite lab services were utilized to handle and analyze the captured sample on location for better contaminants evaluation. In addition, formation mini-DST testing was also conducted to further understand interval rock and pressure properties at larger scale.

The application of this proposed approach is critical to reduce the subsurface uncertainty especially on reservoir and fluid properties; which inputs are used to prudently design future field development facilities. Field data and workflow demonstrating formation evaluation techniques will be presented in this paper. Lesson learned and best practice will also be explained supported by lab analyses and results.

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