Creating a Blueprint for Successful CCS in Southeast Asia: Roadmap to a Sustainable Future

Abstract An increase in carbon capture and sequestration (CCS) activities around the world to fulfil the United Nations (UN) sustainability development goals (SDG) are being observed. Static and dynamic characterization of reservoirs with assessment of caprock integrity are essential to prove that a geological site has the required properties for safe and long-term CO2 storage. The pore-pressure and fracture gradient of the caprock and reservoir are important to establish boundaries that ensure formation integrity and maximum injectivity, along with collection and analysis of representative core data. The project's evaluation program included comprehensive caprock, reservoir, and fracture characterization, along with core analysis—for robust modeling and prediction leading to a successful injection and long-term measurement, monitoring, and verification (MMV) process. Recently for a well in Southeast Asia, the wireline formation evaluation program extended from evaluating the quality of differentially depleted target gas reservoirs to characterizing the overburden; thereby, providing important data for building an accurate CCS geomechanical model. Advanced logging technologies, including 3D acoustics and triple-combo logs with digital support for advanced processing, were combined to accurately characterize rock parameters and provide contextual insights into reservoir and geomechanical models. The analysis of main petrophysical parameters, rock strength, and acoustic anisotropy were analyzed in near real time using digital techniques to accelerate decision making. The only method to directly measure minimum and maximum horizontal stress for reservoirs and caprocks was to use a dual- packer formation tester (FT) for a stress test survey, or MicroFrac operation. By measuring the pressures and injection rates during fluid injection into the formation by the packers and the subsequent falloff periods using a novel combination of techniques, the MicroFrac operation (including four successful stations) determined the horizontal stresses for the first time in a Southeast Asia well for CCS application. The successful integration of stress tests and digital sonic data provided a fully calibrated stress profile. In addition, calibrated maximum and minimum stresses and vertical elastic properties were determined for advanced geomechanics modelling. The mechanical earth model (MEM) was then calibrated and used directly to define the CO2 injection plan. Furthermore, the additional sonic acquisition already planned to characterize deeper reservoirs provided the opportunity to perform novel 3D far-field mapping of dips, layering, and potential fractures deeper in the reservoir and provide additional insight to support stress test interpretation and structural modeling. High-quality cores were obtained and analyzed in the laboratory to conduct advanced testing. Important values of accurate logging design, real-time optimization, interpretation, and data integration are presented with a focus on CCS applications. This paper presents a complete process, from job design, real-time monitoring, MicroFrac operation, to the building and calibration of an MEM; thereby, creating a blueprint for CCS activities.