Carbon Capture and Storage (CCS) Fundamentals

As global industries work to reduce greenhouse gas emissions, carbon capture and storage (CCS) has become a critical technology for mitigating climate impact. In the natural gas sector, CCS is not simply an optional environmental measure but an essential requirement for developing high-CO₂ gas reservoirs. It provides a long-term solution for permanently isolating large volumes of carbon dioxide from the atmosphere.

The CCS value chain consists of three main stages: capture, transport, and permanent storage. The process begins at the gas processing facility, where technologies such as amine absorption systems, membranes, or cryogenic separation units are used to isolate CO₂ from the hydrocarbon stream. Once separated, the CO₂ is sent to a multi-stage compression system where its pressure is increased significantly, typically above 1,100 psi, to convert it into a dense, supercritical state. In this form, CO₂ behaves as a dense fluid and can be transported efficiently over long distances through pipelines or by specialized shipping systems to a designated storage site.

Permanent storage is achieved by injecting the supercritical CO₂ deep underground into carefully selected geological formations, typically at depths greater than 2,600 feet (800 meters), where pressure conditions keep the CO₂ in a dense phase. The two primary storage options are deep saline aquifers and depleted oil and gas reservoirs. Depleted reservoirs are particularly attractive because their geological seals have retained hydrocarbons for millions of years, and existing subsurface data provides strong confidence in storage capacity and structure. To ensure long-term containment, operators implement comprehensive Measurement, Monitoring, and Verification (MMV) programs. These include time-lapse seismic imaging, satellite-based deformation tracking, downhole pressure measurements, and shallow groundwater sampling. Together, these tools confirm plume stability and ensure that injected CO₂ remains securely contained over time, supporting reliable and verifiable emissions reduction.