Imaging and characterization of microporous carbonates using confocal and electron microscopy of epoxy pore casts

Ahmed Hassan, Viswasanthi Chandra, Maxim Yutkin, Tadeusz Patzek, D. N. Espinoza

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Microporous carbonates contain perhaps 50% of the oil left behind in current projects in the giant carbonate fields in the Middle East and elsewhere. Pore geometry, connectivity, and wettability of the micropore systems in these carbonates are of paramount importance in finding new improved-oil-recovery methods. In this study, we present a robust pore-imaging approach that uses confocal laser scanning microscopy (CLSM) to obtain high-resolution 3D images of etched epoxy pore casts of the highly heterogeneous carbonates. In our approach, we have increased the depth of investigation for carbonates 20-fold, from 10 mm reported by Fredrich (1999) and Shah et al. (2013) to 200 mm. In addition, high-resolution 2D images from scanning electron microscopy (SEM) have been correlated with the 3D models from CLSM to develop a multiscale imaging approach that covers a range of scales, from millimeters in three dimensions to micrometers in two dimensions. The developed approach was implemented to identify various pore types [e.g., intercrystalline microporosity (IM), intragranular microporosity (IGM), and interboundary sheet pores (SPs)] in limestone and dolomite samples.
Original languageEnglish (US)
Pages (from-to)1220-1233
Number of pages14
JournalSPE Journal
Issue number03
StatePublished - Jun 13 2019

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We thank the reviewers for their insights and thorough advice, which improved this paper immeasurably. We thank James D. Frost and Gregory J. Vardilos for fruitful discussions of the epoxy-impregnation procedure. We thank Munir Aldin, Robert Patterson, and Bill Mickelson for their valuable input to the design of the high-pressure vessel. We are grateful to the Imaging and Characterization Core Laboratory team at King Abdullah University of Science and Technology (KAUST), Saudi Arabia, especially to Wei Xu and Ali Behzad, for their support in using the CLSM and SEM equipment. We thank the KAUST Visualization Core Laboratory team for their assistance in using Avizo. This project has been funded by KAUST through the Ali I. Al-Naimi Petroleum Engineering Research Center.


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