Home – Home – Jornals – Russian Geology and Geophysics 2018 number Неопубликованное

This study assesses the capabilities and prospects for reinterpreting legacy electrical well logging data acquired in gas-bearing Cretaceous reservoirs of Arctic fields in Western Siberia. The limited suite of electrical logging measurements acquired in older wells in northern fields, together with the specifics of the geoelectric conditions, makes it necessary to rely primarily on lateral logging sounding (BKZ) data. In intervals with pronounced vertical heterogeneity, these data are difficult to interpret because of the unfocused response of the gradient arrays. However, previously disregarded features of the acquired data can now be accounted for, substantially improving the reliability of interpretation results. One approach that implements this concept is multilayer inversion. Multilayer inversion was applied to analyze well logging data from more than fifty wells in the Yamal-Gydan, Nadym-Pur-Taz and Yenisei-Khatanga regions. Detailed geoelectric models were constructed for the Pokur, Tanopcha, and Shuratov formations. The results show that multilayer inversion can substantially enhance the informativeness of legacy electrical logging data, enabling determination of the electrical resistivity of reservoir beds that cannot be reliably evaluated using layer-by-layer approaches. Under the geoelectric conditions considered, improving the accuracy and resolution of resistivity estimates may lead to a substantial refinement of hydrocarbon reserves. The results demonstrate the potential of electrical log processing approaches that account for the influence of heterogeneous shoulder beds when reinterpreting well logging data. The most promising targets for reinterpretation are intervals characterized by complex geoelectric conditions, where the results of layer-by-layer interpretation are most prone to error.