Micro X-ray Computed Tomography-Based Image Analysis for Comprehensive Petrophysical Characterization of Sandstone

Abstract

Petrophysical properties are critical for accurate exploration and production of oil and gas. Specifically, sandstone reservoirs pose a great challenge to oil extraction

due to their specific characteristics including permeability variability, tortuosity, com- paction and cementation, saturation, capillary trapping, and reservoir heterogeneity.

To date, extensive research has been conducted on sandstone reservoirs to understand

oil recovery strategies. However, there remains a lack of in-depth studies on the spe- cific properties of sandstone reservoirs in Pakistan, hindering optimal extraction and

recovery strategies. To overcome this gap, the study marks the first comprehensive

investigation in Pakistan, employing advanced image-based methods such as Micro X- ray CT Imaging, Digital Image Processing (DIP), and Pore Network Modeling (PNM),

coupled with spectroscopic techniques.

Datta sandstone extracted from Toot Oil-filed located in the Attock district

of Punjab, Pakistan, was acquired from the Hydrocarbon Development Institute of Pak- istan (HDIP) and was subjected to Micro X-ray CT Imaging, providing insights into

pore space distribution and characteristics. This imaging quantified parameters such as porosity, pore diameter, connectivity, and tortuosity. Pore Network Modeling was

then employed to assess pore space connectivity and geometrical characteristics, en- abling the estimation of absolute permeability. Energy-Dispersive X-ray Spectroscopy

and Fourier Transform Infrared spectroscopy were also utilized to identify the elemen- tal composition and mineral presence in the sandstone. Notably, the application of

Micro X-ray CT, DIP, and PNM provided a rapid and cost-effective alternative to conventional core analysis of Datta sandstone.

xii

List of Figures

The results revealed an average porosity of 10% and an average pore di- ameter of 0.0777 mm. The tortuosity value obtained was 1.1939, and the estimated

average permeability was 87.18 mD. These values are fairly significant for oil recov- ery procedures which closely aligns with the experimental values as well (Percentage

Errorporosity: 16.4% and Percentage Errorpermeability: 44.1%). Elemental and chemical composition analysis revealed the presence of key minerals such as quartz and feldspar, providing valuable insights into reservoir quality and behavior which is the need of the time for the energy sector. Overall, this study can effectively contribute to the energy sector by enhancing our understanding and optimizing hydrocarbon recovery strategies in the Datta sandstone reservoir.