The paper considers the features of changes in reservoir properties of productive formations of the lower subsuite of the Pokurskaya formation depending on their lithological and mineralogical composition, texture of rocks, filtration-capacitive and porometric characteristics. The feature of the studied formation is its high geological heterogeneity, both vertically and laterally. As a result of the complex analysis of geophysical well logs and laboratory studies of core, it was established that according to petrophysical properties productive deposits can be divided into several petrotypes. The petrotypes in this work are defined as separate groups of rocks characterized by common key parameters: porosity, clay content, residual water abundance, permeability. These coefficients are interrelated and depend on mineralogical and granulometric composition, pore space structure, wettability and other factors reflecting the conditions of sedimentation and subsequent secondary transformations. The analysis of the core sample collection in the section has identified five main petrotypes: massive rocks, layered rocks, clay rocks, carbonized (dense) and angular rocks. For further prediction of petrotypes in wells without core selection, qualitative and quantitative criteria on the standard set of geophysical well logging are justified. The criteria obtained can be used both to clarify the filtration and capacity properties of the section during geological modeling and to make operational decisions on adjusting the drilling trajectory when drilling horizontal wells.
References
1. Kasatkin V.V., Svetlov K.V., Miropol'tsev KF., Shilov Yu.I., Correlation of continental genesis strata: the case of the Pokur formation of the Beregovoye field (In Russ.), Aktual'nye problemy nefti i gaza, 2021, no. 4(35), pp. 13–20, DOI: https://doi.org/10.29222/ipng.2078-5712.2021-35.art2
2. Kontorovich A.E., Ershov S.V., Kazanenkov V.A. et al., Cretaceous paleogeography of the West Siberian sedimentary basin (In Russ.), Geologiya i geofizika = Russian Geology and Geophysics, 2014. V. 55, no. 5, pp. 745–776.
3. Privalova O.R., Taygina M.E., Asylgareev I.N., Integration of well logging surveys and core research data to substantiate the operation of productive intervals using the example of poorly studied Cenomanian carbonate deposit (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2024, no. 9, pp. 45–49,
DOI: https://doi.org/10.24887/0028-2448-2024-9-45-49
4. Amineva G.R., Burikova T.V., Savel'eva E.N. et al., Criteria for revealing petrophysical rock types using well logging in the Middle Carboniferous section of oil fields in North-Western Bashkortostan (In Russ.), Vestnik akademii nauk RB, 2020, V. 35, no. 2, pp. 26–35, DOI: https://doi.org/10.24411/1728-5283-2020-10203
5. Tiab D., Donaldson E C., Petrophysics: theory and practice of measuring reservoir rock and fluid transport, Elsevier Inc., 2004, 926 p.
