Project Summary

Tracers are marker chemicals used for many processes. In CCS they are injected along with the CO2, to help distinguish it from naturally occurring CO2.

They are useful to locate the plume and recognise its migration character. If well understood, they can also be used to determine trapping processes. When a tracer is injected with the CO2, some of the tracer dissolves (partitions) into the formation water whilst the rest of it remains in the COcloud.

Knowing the partition information for a range of tracer chemicals will result in:

  • Improved estimates and correlations for calculating reservoir capacity, and
  • Improved and accurate simulation of the tracers within a range of subsurface temperatures.

This project established general methods for determining the coefficients for other chemical tracers. The study has experimentally determined the partition coefficients for a number of chemical tracers relevant to CCS. These included both reactive ester tracers, useful for determining residual COsaturation using the single well chemical tracer test, and inert gas tracers, useful for inter-well tests and reservoir to surface tests. This data was then incorporated into computational simulations of CCS scenarios to understand the impact of partition coefficients on the interpretation of tracer field data.

Key conclusions:

  • The temperature dependent behaviour of the partition coefficients for a number of reactive ester tracers was determined. This information will lead to more accurate predictions of residual COsaturation in instances where these chemical tracers are used for the single well chemical tracer test.
  • In computational simulations of inert gas tracers, it was determined that, for bounded reservoirs, the behaviour of a chemical tracer is affected to a very minor extent by changes in the partition coefficient (air/ water vs. supercritical CO2/water); while for unbounded reservoirs, the differences are somewhat significant and could possibly be differentiated in a field trial.
  • Future work could include slim tube experiments packed with various sediments to experimentally determine the breakthrough curves for chemical tracers. This information could be used with future field studies to determine the possible influence that sorption onto sediment surfaces actually has on the behaviour of chemical tracers.

Available Reports

Chemical Tracer Partition Coefficients for CCS

The primary aims of this project are to establish general methodologies for determining supercritical carbon dioxide/water partition coefficients for chemical tracers and to determine these in a series of laboratory experiments for a variety of chemical tracers relevant to CCS.

Project Name:
Fundamentals of tracer applications for CO2 Storage

Research Organisation:

Completed, 2013

Matthew Myers, Tara La Force, Cameron White, Bobby Pejcic, Linda Stalker and Andrew Ross


Research Program: Carbon Transport + Storage
Demonstration: General (Carbon Transport + Storage)
Research Focus: Containment, Tracer Applications

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