Automation of petroelastic modeling and analysis of elastic properties contrast using the example of Achimov deposits in Western Siberia

The paper presents the experience of using optimization algorithms to automate the process of setting up petroelastic models of Xu - White and stiff-sand on the example of Achimov deposits of one of the fields of Western Siberia. The use of differential evolution and dual annealing methods enabled to obtain the parameters of petroelastic models with the smallest error within reasonable limits. Probability density function plots and logistic regression method are used to analyze the contrast and obtain decisive rules for rock class separation. This approach provides a statistically correct solution with a quantitative assessment of the contrast in the form of a metric. For the modeled elastic property curves, separation into reservoir and nonreservoir at the log scale and separation with significant or no overlap at the seismic scale is noted. Under the assumption that the wells did not penetrate the maximum possible thicknesses of the Achimov reservoirs in the area, the elastic properties were modeled for five scenarios of increased effective thicknesses relative to the baseline. The result of contrast analysis showed confident separation in the field of acoustic impedance and the ratio of primary and shear wave velocities at values of the ratio of effective and total thicknesses greater than 0,4. Such reservoir thicknesses are unlikely for prospective objects of the study area according to actual data.

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