Application of Curve Reconstruction Technology in Lithology Identification for Tight Glutenite Reservoirs—Taking Oilfield N in South Turgay Basin for Example

Abstract

Lithology identification is the basis of reservoir evaluation, and improving coincidence rate of lithology judgment is key to evaluate complex glutenite reservoirs. Layer J₂ds of Oilfield N in the South Turgay Basin of Kazakhstan is a tight glutenite reservoir with complex lithology and strong heterogeneity, where adopting the conventional crossplot consisting of logging curves will result in low accuracy of lithology identification. In this study, a method is proposed for identifying lithology of glutenite reservoirs based on curve reconstruction. Firstly, the key lithology is determined using core and logging data, the density (DEN) and sonic time difference (DT) curves that are sensitive to the reservoir lithology are selected, and curve reconstruction is done to amplify the response value of logging curves; then, reconstructed curves are used to build a crossplot, and the quantitative identification of the complex glutenite reservoir lithology is done. Using this method, it is identified that, in terms of lithology, the reservoir in this area mainly consists of siltstone, fine sandstone, medium sandstone, conglomeratic coarse sandstone, medium conglomerate, etc. The identification results are consistent with the actual situation, and thus the difficulty in identifying complex lithology is effectively dealt with, providing guidance for the subsequent exploration and development of the oilfield, and the ideas for other similar research on reservoirs. Therefore, such method is worthy of promotion.

Copyright 2022, IFEDC Organizing Committee

This paper was prepared for presentation at the 2022 International Field Exploration and Development Conference in Xi’an, China, 16–18 November 2022.

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