Subsurface Data Acquisition and Operational Excellence in ADNOC’s First CCS Well in the UAE

Abstract As a key milestone in ADNOC’s sustainability initiatives and to support the UAE’s net-zero goals, a major CCS project was initiated, focused on permanent CO2 storage in deep carbonate saline aquifers in onshore Abu Dhabi (Abu Dhabi Environment Report, 2017). Following a comprehensive feasibility study (Xu et al, 2022), a combined appraisal and injection site was selected and the first commercial CO2 injection well was completed in 2023. This paper reports the outcomes of a comprehensive operational data driven acquisition program across two major saline aquifer reservoirs; Formation A and Formation B as well as across caprocks overlying these reservoirs. Data analysis involved the combination of wireline logs, core data and formation pressures and fluid sampling. Iterative cross discipline involvement in the well design for the first CCS well was critical to achieve the data acquisition goals of the well (Figure 1). Key challenges involved integrating well data outcomes and conducting mini frac tests to evaluate the seal integrity of the overlying formations and confirm the reservoir rock quality and variability in A and B formations, which are under-explored in this part of the UAE. The cap rock integrity was assessed by conducting multiple mini-frac tests in the Caprock and A formations. Drilling and logging programs were designed to ensure that reliable micro-frac tests and image log pre-post frac could be conducted. The results showed that the breakdown pressure in the caprock formation indicates a strong sealing capacity. Quantification of reservoir quality and characterizing the heterogeneity was important, so core analysis was fast tracked and then matched with NMR results from the data acquisition. This dataset, combined with dynamic information, will be a crucial source for validating future CCS wells performance in UAE. Once primary data acquisition was achieved across the reservoir and caprock intervals, all subsurface data analysis was carried out simultaneously and fast-tracked to ensure effective and reliable information was available to optimize decisions for the well to deliver on UAE’s net-zero aspirations strategy.