Exploring CO2 Sequestration Potential Within the Al-Wajh Formation of the Yanbu Basin
Authors: Lozano Mauricio , Zerpa Jordania , Afifi Abdulkader M. , Hoteit Hussein 
Published: November 2024

Abstract
Saudi Arabia has committed to reducing emissions by 278 million tons per year (mty) of avoided carbon dioxide (CO2) by 2030 and achieving net zero emissions by 2060. Approximately 35% of the country's carbon emissions originate from the western region along the Red Sea. This study aims to comprehensively assess the effectiveness of Carbon Capture and Storage (CCS) in the Al-Wajh Formation of the Yanbu Basin, Saudi Arabia. The primary goal is to evaluate the potential for CO2 sequestration using a combination of advanced reservoir static modeling and numerical simulations. The methodology involves constructing a detailed 3D geological model of the Al-Wajh Formation, utilizing basin and well data, along with information from analogous geological sites. The workflow incorporates seismic data, well logs, depth maps, and petrophysical data to create an accurate 3D representation of the geological formation. The identified storage site is strategically located near major industrial facilities that emit more than 50 million tons of CO2 annually. Carbon dioxide can be captured from these industrial sources and injected into the geological formations. The injection process is analyzed through numerical simulations, including sensitivity analyses, to evaluate the impact of various geological parameters on CO2 migration and trapping mechanisms. By integrating geological and geophysical data, the study aims to provide a detailed understanding of the storage capacity and long-term fate of CO2 sequestration in this region. Simulation results indicate that approximately 2.8 million tons of CO2 can be injected annually into the Al-Wajh Formation using four injection wells. Over a 50-year period, this could result in the sequestration of over 146 million tons of CO2. Key findings highlight effective solubility trapping during the injection phase and significant residual trapping post-injection, with more than 50% of the CO2 being permanently trapped. The connectivity between the Al-Wajh Formation and the overlying Burqan Formation is identified as a critical factor influencing the storage capacity and overall effectiveness of the CCS process. While the reservoir conditions showed favorable injectivity, uncertainty analysis related to connectivity and the size of the storage site has been conducted. This analysis identified scenarios where over-pressurization may occur, posing a risk of CO2 leakage, which necessitates the incorporation of relief wells. This study offers novel insights into the feasibility and effectiveness of CCS in the Yanbu Basin, enhancing the broader understanding of geological sequestration mechanisms in the Al-Wajh Formation. It demonstrates the practical application of CCS technology in a major industrial region, employing advanced simulation techniques to quantify sequestration potential and optimize CCS strategies. The findings provide valuable guidance for potential CCS projects in Saudi Arabia, supporting the country's climate change mitigation goals.