CO2 Capture and Storage for Enhanced Gas Recovery
Advancing understanding of CO2 storage and recovery processes with tracer technology.
Carbon capture, utilization and storage (CCUS) involves capturing CO2 at industrial facilities, re-using it or storing it to prevent leaks back into the atmosphere. K12-B is the first site in the world where CO2 was injected into the same reservoir where it was produced at a depth of about 4000 meters (about 2.49 miles) in a mature gas field. The main objective was to investigate the feasibility of CO2 injection and storage in depleted natural gas fields on the Dutch continental shelf. As a part of the CRUST project launched by the Dutch government in 2002, it aims to make an inventory of possible sequestration sites to study possibilities as well as legal and environmental aspects for CO2 re-use.
Although CCUS plays an important role in the energy transition, there are many unknowns regarding point-source capture, transportation and storage, as well as its long-term environmental impact on permanent CO2 facilities. In particular, it is challenging to determine the potential for both CO2 storage and enhanced gas recovery (EGR) in mature fields.
Tracer technology was used to advance the overall understanding of CO2 capture and storage, helping to trace the migration pathways with high precision. The total volume of each tracer injected in well K12-B6 was one cubic decimeter. They were used to measure the injection rate of the CO2, composition of the injected CO2 and pressure and temperature at various locations. Additionally, tracers help to understand the composition of the gas and water produced and the integrity of the CO2 injection tubing.
The tracers allowed for an accurate assessment of the flow behavior in the reservoir and the related sweep efficiency of the injected CO2. They helped to demonstrate physical communication between K12-B6 (the CO2 injection well) and K12-B1 the (nearest producer well) with the detection of both tracers in the gas stream of K12-B1. The use of tracers has significantly contributed to an improved understanding of the reservoir and how the complex down-hole pressure data could best be interpreted. Without the tracers, it would be difficult to accurately determine the physical communication between the injector and producers because the injected CO2 originates from the reservoir gas and, therefore, cannot be distinguished from the naturally occurring CO2 in the reservoir gas.
Tracer technology can help to improve accuracy and advance the overall understanding of CO2 storage and recovery processes, serving as markers to verify the integrity of the CO2 sequestration site. Tracers offer valuable insights into the behavior of injected CO2 and the effectiveness of storage and recovery processes, helping to monitor CO2 movement with precision. Any unexpected movement or escape of tracers can indicate potential issues, allowing for early detection and remediation to prevent environmental risks and ensure safe long-term storage.