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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Improving the Reliability of Quantitative Interpretation of the Nuclear Magnetic Logging Data to Evaluate the Secondary Porosity in Res-ervoirs Associated with the Ovinparmian and Grebenian Horizons in the Trebs fieldстатья
- Авторы: Shumatbaev K.D., Privalova O.R., Gainullina E.K., Korost D.V., Belokhin V.S.
- Сборник: SPE Russian Petroleum Technology Conference, 16-18 October, Moscow, Russia
- Год издания: 2017
- Место издания: Society of Petroleum Engineers www.onepetro.org/conference-paper/SPE-187908-MS
- DOI: 10.2118/187908-MS
- Аннотация: The study deals with improving the reliability of interpreting the data of the nuclear magnetic logs (NML) to analyze the secondary porosity in fractured vuggy porous carbonate reservoir rocks. According to routine practice the interpretation of the laboratory NMR data is accompanied by calibration/matching against results obtained using other techniques (capillary measurements, centrifugation, mercury injection) to justify the validity of relaxation time cut-off values T2 (T2 cutt-offs) corresponding to the volume of bound (residual) water saturation. At the same time, association of the pore volume with the dominant large size elements (vugs) involves an empirically introduced T2_Cav=750 ms cut-off [1, 2, 3]. There is no operation involved to validate adjusting above value that is partially dealing with the methodological hurdle to assess the share of the pore volume occupied by vugs during core studies. This study proposes an approach to assess the fraction of the vuggy porosity using X-ray computer microtomography (micro CT) technique with subsequent matching against the NMR data resulting in estimating correct T2_cav cut-off values for the vuggy component. We used a standard set (having diameter of 30 mm) of core samples to carry out a series of petrophysics laboratory studies involving NMR and micro CT. We calculated the void space associated with the vuggy porosity on the basis of micro CT data. We adjusted the value of T2_Cav in each of the samples studied to proceed with determining two main values of T2_Cav based on morphology (size and shape) characteristics of the vug types. The results obtained were used to analyze and correct NML data. During these studies we tested the method of matching T2_cav cut-offs in carbonate sediments of the Lower Devonian and Upper Silurian deposits in the Trebs field. The results obtained clearly demonstrate that T2_cav cut-off values can vary in different manner depending on the specificity (size and morphology of vugs) in the studied cross section.
- Добавил в систему: Корост Дмитрий Вячеславович