Innovative tracer injection in K12-B

T2013-11-CCUS innovative tracer injection in K12-B CATO-2

Publieke samenvatting / Public summary

Summary

This project aimed to identify and characterise suitable chemical tracers that migrate in a way that is comparable to injected CO2.The primary goal of this collaborative project was the injection of these tracers at gas production site K12-B, resulting in a better understanding of carbon dioxide and chemical tracer flow behaviour in an offshore enhanced gas recovery scenario. Injecting the tracers from an online off-shore gas production facility proved to be very complex and time-consuming. The actual sampling and analysis of the tracers could not take place as the B1 operator stopped producing. However, a successful collaboration was established between the Dutch and Australian partners that might lead to combined lab experiments in the CSIRO labs with similar goals to those of this project. A workflow was created regarding the sampling, handling and chemical analysis of the four injected tracers.

Background

The injection of CO2 has been suggested as a way to enhance the production of methane (EGR or enhanced gas recovery) in mature gas reservoirs. Simulation studies have indicated that rapid mixing of injected CO2 with ambient natural gas leads to rapid increases in the concentration of the injected gas in the natural gas produced. The prediction was of an additional recovery of 1% or less. Actual field applications, however, report additional recoveries in the order of 10%. 

Project objective

This project explored one of the possible physical reasons for the difference – the impact of retardation of the injected CO2 with respect of the displacement of natural gas – using four innovative chemical tracers. These were to be injected with CO2 at gas production site K12-B. Two of these tracers were intended to mimic the dissolution and hence retardation during the migration of CO2. The other two tracers mimicked the natural gas, minus dissolution and so showing less retardation.

Project results

Injecting these chemical tracers from an online off-shore gas production facility proved to be very complex and time-consuming, with licensing issues and technical problems with the CO2 compressor at the platform and the closest producer. Based on the first tracer test and multiple reservoir simulations, it was estimated that tracer breakthrough would take at least two months. However, the actual sampling and analysis of the tracers could not take place as the B1 operator stopped producing. This made it impossible to reach the complete technical objective of the project.

Despite this, a successful collaboration was established between the Dutch and Australian partners that might lead to combined lab experiments in the CSIRO labs with similar goals to those of this project. A workflow was created regarding the sampling, handling and chemical analysis of the four injected tracers.