A comprehensive assessment of uplift prospectivity of the western slope of the South Tatar arch using integral reservoir prospectivity coefficient

UDK: 550.8:553.98

DOI: 10.24887/0028-2448-2025-7-6-12

Key words: geology, hydrocarbon trap, geological model, variogram, synthetic curves, integral coefficient, exploratory drilling

Authors: R.A. Rakhimzyanov (TatNIPIneft, RF, Almetyevsk), A.M. Kalimullin(TatNIPIneft, RF, Almetyevsk), R.R. Aflyatunov (TATNEFT PJSC, RF, Almetyevsk), A.P. Bachkov (TATNEFT PJSC, RF, Almetyevsk), O.M. Ilmukov (TATNEFT PJSC, RF, Almetyevsk), V.G. Bazarevskaya (TatNIPIneft, RF, Almetyevsk), A.F. Safarov ( TatNIPIneft, RF, Almetyevsk), A.F. Garipov (TatNIPIneft, RF, Almetyevsk), A.V. Levaya (TatNIPIneft, RF, Almetyevsk), I.V. Melnikov (TatNIPIneft, RF, Almetyevsk)

This paper reviews the results of a comprehensive assessment of the prospectivity of structural uplifts on the western slope of the South Tatar arch. The relevance of this study is due to the depletion of major oilfields and the limitations of untapped resources. The main goal is to develop and apply a universal approach to rating of local targets for exploratory drilling in mature areas using an integral reservoir prospectivity coefficient. Twenty-two structures and 235 wells were selected for analysis based on the data obtained from 3D seismic survey (500 km2), well logging, and core and sludge analyses. A 3D geological model, incorporating an interpretation of seismic surfaces, a stratigraphic breakdown, and an extrapolation of reservoir properties, was build using TNavigator software. A geostatistical analysis was used to account for uncertainties in the interwell intervals. Maps of reservoir structures and properties (porosity, permeability, oil saturation, net thickness) were compiled. The evaluation of geological resources was performed using deterministic and probabilistic approaches, together with development scenario analysis and cash flow discounting. Then, the integral prospectivity coefficient was introduced, including parameters of resources, morphology, infrastructure and economic attractiveness. The drilling priority ranking of the selected structures was compiled based on this coefficient. This technique demonstrated high informative values and enabled the identification of the most promising targets, taking into account both geological and economic risks. The obtained results can be applied to exploration planning under a high degree of uncertainty, a limited budget, and late-stage development. This approach can be scaled for similar regions, and integrating it into digital reserve management platforms shall make exploratory decisions more efficient and accurate.

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