We developed software for the numerical simulation and inversion of galvanic and induction log data. The simulation algorithm is based on a finite-element approach to calculating electrical and electromagnetic responses in a 2D model that includes horizontal layers, cylindrical near-borehole zones changed by drilling, borehole with drilling mud and tool body. Unfocused lateral logging tool with gradient arrays) signals are applied to estimate resistivity values in the horizontal and vertical directions, whereas high-frequency electromagnetic sounding tool logs are employed to evaluate the frequency dispersion of electrical conductivity and dielectric constant of formations. Using the developed programs, high-accuracy field data acquired with the SKL logging equipment on the Bazhenov formation intervals in the central regions of Western Siberia were interpreted. We determined the electrophysical parameters of the high-resistivity impermeable Bazhenov rocks. The correlation of the parameters with the data of other logging methods was investigated, with establishing their relationship with the structural-material composition. We compared the frequency-dependent values of electrical conductivity and dielectric constant with the petrophysical core measurements data. The results of the numerical inversion of the electromagnetic log data measured on the Bazhenov formation interval are consistent with the laboratory measurements. We carried out SKL data interpretation with the determination of the material composition, identification of the lithological types and study of the electrophysical parameters of the Formation rocks for the central regions of Western Siberia. By applying the mixture formulas for electrical conductivity and dielectric constant, more than three dozen of litho-electrophysical models and several correlation schemes for the Russkinskoye, Fedorovskoye, Vostochno-Surgutskoye and Tailakovskoye fields were constructed according to SKL logging signals.
References
1. Aksel'rod S.M., The influence of the frequency dispersion of the electrical properties of rocks on the results of determining the resistivity of formations (based on foreign literature) (In Russ.), Karotazhnik, 2007, no. 10, pp. 103–126.
2. Epov M.I., Bobrov P.P., Mironov V.L., Repin A.V., Dielectric relaxation in oil-bearing clayey rocks (In Russ.), Geologiya i geofizika, 2011, V. 52(9), pp. 1302–1309.
3. Anderson B.I., Barber T.D., Luling M.G. et al., Observations of large dielectric effects on LWD propagation-resistivity logs, Transactions of the SPWLA 48th Annual Logging Symposium, Austin, Texas, June 3–6, 2007, paper BB, 11 p.
4. Toumelin E., Torres-Verdin C., Bona N., Improving petrophysical interpretation with wide-band electromagnetic measurements, SPE-96258-PA, 2008, https://doi.org/10.2118/96258-PA.
5. Epov M.I., Glinskikh V.N., Linearization of the relative characteristics of a high-frequency magnetic field in two-dimensional conducting media (In Russ.), Geologiya i geofizika, 2004, V. 45, no. 2, pp. 266–274.
6. Glinskikh V.N., Nikitenko M.N., Epov M.I., Processing high-frequency electromagnetic logs from conducting formations: Linearized 2D forward and inverse solutions with regard to eddy currents (In Russ.), Geologiya i geofizika, 2013, V. 54, no. 12, pp. 1942–1951.
7. Kontorovich A.E., Yan P.A., Zamiraylova A.G. et al., Classification of rocks of the Bazhenov formation (In Russ.), Geologiya i geofizika, 2016, V. 57, no. 11, pp. 2034–2043.
8. Petrov A., Determining the resistivity anisotropy of high-resistivity sediments, based on lateral logging sounding data from vertical wells, SPE-189295-STU, 2017, https://doi.org/10.2118/189295-STU.
9. Petrov A.M., Sukhorukova K.V., Nechaev O.V., Geoelectric model of the Bazhenov formation deposits according to electrical and electromagnetic logging sounding data, Proceedings of EAGE/SPE joint workshop on shale science 2017: Prospecting and development the science of shales: The problem of exploration and development, 2017, paper M12, pp. 5, DOI: 10.3997/2214-4609.20170018.
10. Fedoseev A.A., Glinskikh V.N., Kazanenkov V.A., Relative content of rock-building components and basic lithological types of rocks of the Bazhenov formation and its stratigraphic analogues according to log and core data (In Russ.), Neftegazovaya geologiya. Teoriya i praktika, 2018, V. 13, no. 2, pp. 1–19.
