Work

Experimental and Numerical Evaluation of CO2-Induced Wettability Alteration in Carbonate Reservoir CCUS

Year: 2025

Type: article

Abstract: This study presents both laboratory measurements and numerical modeling of wettability alterations following carbon dioxide (CO2) injection in limestone carbonate reservoirs. Both synthetic and crude oil systems were evaluated using a Drop Shape Analyzer (DSA-100) to quantitatively measure the contact angle and interfacial tension (IFT) on limestone core samples under ambient and reservoir conditions. The results demonstrated that carbonated brine significantly reduced the IFT (2.0–4.1 dynes/cm) and contact angle (11.9–16.0°), indicating a shift toward more water-wet conditions, compared with the modest reductions in contact angle achieved with standard brine (1.6–6.7°). Synthetic fluid systems containing naphthenic acid initially exhibited stronger oil-wet behavior but also experienced wettability alterations when exposed to CO2. A previously developed compositional reservoir simulation model, which was based on assumed relative permeability endpoints, was revised to incorporate the experimental findings of this study as a supporting tool. Incorporating the experimental wettability alteration effect of CO2 in the numerical model by a 5.2% reduction in the residual oil saturation (the relative permeability endpoint) caused 2% increase in the oil recovery factor and 12% improvement in the CO2 utilization efficiency (9780 standard cubic feet per stock tank barrel (SCF/STB) vs. 8620 SCF/STB). Overall, this work provides critical laboratory validation and supports by numerical simulation that CO2-induced wettability alteration is a key mechanism underpinning CO2-based enhanced oil recovery (EOR) and carbon capture, utilization, and storage (CCUS) deployment in limestone carbonate formations.

Source: Energies

DOI: 10.3390/en18205529

Authors: Mohammad Al-Ghnemi, Erdal Ozkan, Hossein Kazemi

Institution: Colorado School of Mines

Language: English

Topic: Enhanced Oil Recovery Techniques

Subfield: Ocean Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $3,137