Developing an Integrated Petrophysical Framework: Structured Approaches to Storage Capacity, Containment and Long-Term Monitoring

Abstract Petrophysics plays a critical role in subsurface characterization and monitoring design for Carbon Capture and Storage (CCS) projects. In Malaysia, regulatory efforts are driving the country's transition towards net carbon zero, with PETRONAS leading initiatives to strengthen CCS capabilities. Regulators and auditors ensure the robustness of subsurface modeling, which includes assessing seal capacity, injectivity, plume migration, and long-term containment for safe CO2 storage. It is also essential to monitor, measure, and verify (MMV) during the pre-, injection, and post-injection stages, during which petrophysicists play a key role. To achieve these objectives, it is vital to build capacity in terms of both skills and projects to adapt to the evolving CCS storage development plans. This paper presents an analysis of industry-standard petrophysical evaluation practices, incorporating recommendations for CCS projects. The study also includes case studies and laboratory results focused on log evaluations, offering insights into robust petrophysical methodologies and potential petrophysical solutions for CCS implementation. We discuss the enhancements in petrophysical evaluations relevant to CO2 storage in depleted oil and gas reservoirs, addressing key challenges and opportunities for improved storage and containment assessment. As the scale and complexity of CCS projects grow, the accuracy and reliability of petrophysical evaluations become even more critical. This paper also explores the application of petrophysical evaluations in scenarios where data is sparse or unavailable, particularly in the context of deep saline aquifers. Additionally, the guidelines include caprock integrity assessments to ensure wellbore isolation and compliance with Plug and Abandonment (P&A) requirements, in line with regulatory standards for CCS projects. These guidelines provide essential methodologies for quantifying storage capacity, assessing containment integrity, evaluating sealing capacity, and supporting the long-term monitoring of the CO2 plume. By advancing petrophysical evaluation methodology, we aim to reduce uncertainties in subsurface modeling, improve risk assessments related to CO2 containment, and enable informed decision-making throughout the CCS lifecycle, ensuring the long-term safety and efficacy of large-scale CO2 storage operations.