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This paper aims to show all the steps involved in a rigorous uncertainty analysis study, completed in 2008, in static and dynamic modeling as well as try to highlight some very key steps for a successful study. Yuzhno Khylchuyu (YK) field is a Permian aged Carbonate reservoir in Timan Pechora basin in European part of Russia. It was discovered in 1981 and has since been appraised by 24 wells. The field is being developed on a regularized waterflood 5-spot pattern with 120-acre well spacing. The productive reservoir is composed of three main zones, A, B, and C. These zones are not in communication based on geo-chemical data and dynamic well test results. Zone A, which is dominantly progradational has good continuity and best reservoir properties containing 90% of the original oil in place (OOIP). Dominantly aggraditional zones B and C are discontinuous, and have poor reservoir properties. The motivation behind a rigorous uncertainty analysis on OOIP and Expected Ultimate Recovery (EUR) was due to the large capital investment required for full field development. Thus, the objective of this study was to quantify the range of uncertainty of OOIP and EUR, to identify the most influential parameters contributing to uncertainties in OOIP and EUR, and quantify the impact of those most influential parameters. Such rigorous uncertainty analysis would thus help mitigate the risks with the investment.

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Комплексный подход при анализе геолого-гидродинамических неопределенностей, нижнепермские карбонатные отложения, Тимано-Печорская нефтегазоносная провинция, Россия А.Ф. Ширази, С.В. Солоницын, И.А. Куваев / КонокоФиллипс Россия Инк.Авторское право 2010 г., Общество инженеров-нефтяников Настоящий документ был подготовлен для презентации на Российской технической нефтегазовой конференции и выставке SPE 2010 в Москве, Россия, 26-28 октября 2010 г.Настоящий документ был выбран для презентации программным комитетом SPE по итогам анализа информации, содержащейся в реферате, предоставленном автором (авторами). Содержание документа не анализировалось Обществом инженеров-нефтяников и подлежит корректировке автором (авторами). Материал не обязательно отражает какие-либо позиции Общества инженеров-нефтяников, его руководителей и участников. Электронное воспроизведение, распространение или хранение любой части данного документа без письменного согласия Общества инженеров-нефтяников запрещается. Разрешение на воспроизведение в печатном виде ограничено рефератом в объеме не более 300 слов, копировать иллюстрации не разрешается. В реферате должно содержаться явное признание авторского права SPE.

Drilling horizontal wells in complex formations is always a challenging task. The development of deep and ultra-deep azimuthal resistivity tools has largely improved the accuracy of the wellbore placement in the target zone. The enhanced imaging provided by the stochastic inversion of the azimuthal resistivity data can be applied for mapping both the internal reservoir structure and fluid contacts in the field. Major oil and gas service companies provide the operator with azimuthal resistivity tools and develop their own algorithms for resistivity data processing. Commonly services companies process azimuthal resistivity data internally. We have developed a vendor-independent stochastic inversion method that is applicable to almost any deep-azimuthal resistivity tools. This module allows operators to carry out real-time geosteering, as well as pre-job and post-job data analyses independently from the service company. This paper demonstrates the examples of the azimuthal resistivity data interpretation using synthetic data and actual data from the well offshore Norway. Calculated inversion models, based on actual data, allowed mapping of the oil-water contact and discontinuities in the reservoir that take place at the resistivity contrast boundaries. The application of this technology can increase the percentage of the horizontal well in the pay zone while letting the operator cut drilling costs through optimizing bottom hole assembly and use more advanced interpretation practices.