prediction of Shale Volume and Water Saturation Using Pre-Stack Seismic and Well-Log Data in an Oil Field

Jelvegarfilband, Ali; Riahi, Mohammad Ali; Bagheri, Majid

doi:10.22050/ijogst.2022.338963.1638

prediction of Shale Volume and Water Saturation Using Pre-Stack Seismic and Well-Log Data in an Oil Field

Document Type : Research Paper

Authors

Ali Jelvegarfilband ¹

Mohammad Ali Riahi ²

Majid Bagheri ³

¹ 1 Department of Petroleum Engineering Faculty of Civil and Earth Resources Engineering, Islamic Azad University, Central Tehran Branch, Tehran, Iran

² 2 Professor, Institute of Geophysics, University of Tehran, Tehran, Iran

³ 3 Associate Professor, Institute of Geophysics, University of Tehran, Tehran, Iran

https://doi.org/10.22050/ijogst.2022.338963.1638

Abstract

The petrophysical parameters of the Ghar Formation are characterized in this study. A combination of pre-stack seismic data gathers and well-log data is used to estimate water saturation and shale volume in the Ghar reservoir. First, the highest possible correlation between the well logs and the seismic inversion data was established for this purpose. After extracting the optimal wavelet, an accurate relationship between the estimated values and the core data was obtained. Next, using data from another well, the validity of the constructed model was examined. The results showed that the combination of three attributes—instantaneous cosine of phase, , and —can accurately estimate the shale volume of the reservoir, with a correlation coefficient of approximately 70%. Although the two layers in the Ghar section have a shale volume of about 10%, the overall shale volume in the reservoir area is negligible. The logarithm of the ratio of compressional wave velocity to shear wave velocity attribute exhibits the highest correlation, approximately 62%. Finally, validation using previously unutilized well-log data demonstrated an accuracy of about 90% in predicting these properties.

Highlights

· Shale volume and water saturation are important petrophysical parameters that can help identify reservoir zones more reliably.
· To achieve the most accurate predictions, seismic attributes were analyzed, and those showing the highest correlation with water saturation and shale volume were selected.
· The validation demonstrates the effectiveness of this method in predicting water saturation and shale volume using pre-stack inversion and well logs.

Keywords

Pre-stack seismic gathers

Reservoir shale volume

Seismic attributes

Water saturation

Well logs

Subjects

Petroleum Engineering – Exploration

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