Capillary-Sealing Efficiency of Mica-Proxy Caprock for CO2/H2 Geologic Storage in the Presence of Organic Acids and Nanofluids

Abstract

Summary Toward a diversified low-carbon future, the geological storage of carbon dioxide (CO2) and hydrogen (H2) is regarded as a key enabler for an industrial-scale implementation. However, many geological formations, such as depleted oil and gas reservoirs, can contain inherent traces of organic molecules that dramatically affect their storage capacities and caprock sealing efficiency. Hence, using the right analysis to accurately determine the caprock sealing efficiency and storage capacity in the presence of organics is crucial for a secure and safe storage process. This study analyzed the sealing potential of a proxy caprock (mica) by calculating the capillary entry pressure and static column height of CO2 and H2 using previously published contact angle measurements. In addition, the effects of key parameters such as pressure (up to 25 MPa), temperature (308 K, 323 K, and 343 K), and pore throat size (r = 5 nm and 10 nm) were demonstrated, along with those of organic acids (lignoceric acid C24, stearic acid C18, lauric acid C12, and hexanoic acid C6) and alumina nanofluids, on the wettability, capillary sealing efficiency, and static column height of the gas. The results indicated that the sealing efficiency and storage capacity for CO2 and H2 decrease with the increase in pressure and surface concentration of organic acid but increase with the increase in temperature. The analysis demonstrated a theoretical inverse relationship between the capillary entry pressure and the pore throat radius. Thus, the smaller the pore size, the more suitable the conditions for sealing and storage capacity. Furthermore, the wettability and sealing efficiency of the organic-aged mica/CO2 system were improved by the addition of nanoalumina, with an optimal nanofluid concentration of 0.25 wt%. In a nutshell, this work has provided a detailed theoretical workflow for assessing the influence of various parameters on the wettability, sealing efficiency, and storage capacity of mica substrates (as a proxy caprock) for the safe and secure geological storage of H2 and CO2.

Impact of Methylene Blue on Enhancing the Hydrocarbon Potential of Early Cambrian Khewra Sandstone Formation from the Potwar Basin, Pakistan

“…The global energy demand is rising and projected to increase significantly in the upcoming years , and may even increase by around 60% by 2040, primarily due to population growth, urbanization, and economic development in many countries. − Crude oil is the principal source of energy worldwide, and the increasing number of depleted oil reservoirs (containing approximately 70% of the remaining crude oil) requires immediate attention. , Hence, the development of innovative production enhancement strategies is essential in order to cope with the increasing energy demand and to optimize recovery from existing hydrocarbon fields. , Several enhanced oil recovery (EOR) methods, such as chemical EOR and thermal EOR, are used to increase the recovery and sweep efficiency during water flooding and gas injection. − In this respect, the wettability of the rock is an essential parameter for improving the trapped oil recovery and sweep efficiency. , However, subsurface formations are naturally contaminated with organic acids, which renders them hydrophobic − and leads to the early breakthrough of injected fluid, which leaves behind large volumes of hydrocarbons. , …”