WETTABILITY QUANTIFICATION IN ROCK COMPONENTS VIA WATER ADSORPTION ISOTHERMS
Downtown Houston
Speaker:
Seminar Date: Aug 21 2024
Registration Opens: Jul 24 2024 - Aug 22 2024
Time: 12:00 PM - 01:00 PM (US CDT)
Admission/Registration Link: None
Donation Link: None
Meeting/Webinar Link: https://register.gotowebinar.com/register/4576179930225187415
Contact: Artur Posenato Garcia (VP Downtown, SPWLA Houston Chapter)
Corresponding: vpdowntown@spwla-houston.org
Fees: FREE
ABSTRACT:
Multiple conventional experimental methods are available to estimate wettability, such as contact-angle measurements and imbibition tests on core samples. Although commonly used, the inconsistency in wettability assessment from these methods challenges the wettability quantification in mixed-wet rocks. Moreover, new reliable methods for wettability assessment in both homogeneous and heterogeneous surfaces, and in core samples that have a variable range of wetting states are still needed. The concept of adsorption is fundamental to understanding fine-scale interactions between solids and fluids and potentially can be used for wettability assessment. For the first time, in this paper, we aim to conduct a systematic study on the relation between water adsorption and wettability. We experimentally compute water adsorption isotherms and perform sensitivity analysis on the impacts of (i) wettability levels, (ii) types of rock components, and (iii) concentrations of mineral constituents on water adsorption capacity. We synthetically change wettability of pure quartz powder to obtain samples with variable wettability level. Subsequently, we use part of the chemically treated powders to create pellets and measure contact-angle. On the remaining portion of the treated powders, adsorption isotherms are measured using a Dynamic Vapor Sorption Analyzer (DVS). We also obtain water adsorption isotherms on several types of pure minerals and organic components, including diverse clay types, quartz, calcite, and kerogen. Finally, different minerals are mixed at distinct concentrations to evaluate the effect of composition on adsorption capacity. Results demonstrated that Ca-montmorillonite exhibits more water adsorption than the other minerals, reaching adsorption of 0.23 grams of water per gram of Ca-montmorillonite at 90% relative humidity. We also measured water contact-angle on the pure minerals and found that on these samples, the water droplet completely spreads, demonstrating a 0°contact-angle. After chemically changing the wettability of quartz, a contact-angle of 120° was obtained. The adsorption isotherms show that the change in wettability of quartz resulted in a decrease of approximately 40% in the amount of water adsorbed at 80% relative humidity. A comparison of the water contact-angle with adsorption isotherm measurements, suggests that the isotherms are more sensitive to variations in wettability than contact angle. Water adsorption on immature kerogen is found to be larger compared to most of the evaluated minerals. Results also suggested that the structure of kerogen is flexible and capable of large water uptake. Adsorption isotherms estimated on mixtures of minerals also proved that these measurements are extremely sensitive to small variations in the mineral composition. We proved that the fine-scale solid-fluid interfacial interactions can be quantified with adsorption isotherms and upscaled to wettability. The outcomes of this work also demonstrate the affinity of individual rock components to water. These results can potentially be used for further development of new methods for wettability assessment of mixed-wet rocks and rocks with complex mineral composition.
BIOGRAPHY:
Isa Silveira de Araujo is a PhD candidate in the Hildebrand Department of Petroleum and Geosystems Engineering at The University of Texas at Austin. She earned her B.S. degree in Chemical Engineering from Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Brazil, and her M.S. degree in Chemical Engineering from the University of Campinas (Unicamp), Brazil. She is one of the recipients of the 2022 SPWLA Distinguished Speaker Award. She is also the recipient of Osmar, Mercedes, and Roberto Abib Memorial Endowed Presidential Scholarship in Petroleum Engineering from the Cockrell School of Engineering. Her research interests focus on the petrophysics of unconventional reservoirs and rock-fluid interactions.