Enhanced gas recovery testing in the K12-B reservoir by CO2 injection a reservoir engineering study

Gaz de France Production Netherlands B.V. (GPN) is producing natural gas from the Dutch North Sea continental shelf. As one of the players in the Dutch gas supply market, GPN supports the idea of injecting CO2 into depleted gas fields in order to reduce CO2 emissions into the atmosphere.

The gas produced at one of GPN’s platforms, the K12-B platform, contains a relatively high proportion of CO2. This CO2 used to be separated from the produced natural gas and released into the atmosphere. The K12-B reservoir is located at a depth of some 3800 metres; with a hydrostatic pressure regime and a formation temperature of 132°C. Preliminary investigations indicated that it would be relatively easy to re-inject this CO2 back into the reservoir. Hence GPN’s K12-B platform offered a good opportunity to test CO2 injection at large depths. Deployment of a CO2-injection demonstration facility at the K12-B platform has increased our understanding of the benefits and drawbacks of this technique.

This paper reports on the results of phase 2 of the ORC project - Offshore Re-injection of CO2. It covers the findings of the CO2 re-injection test into a gas-producing compartment of the K12-B reservoir. At the end of 2005 there was no clear evidence of measurable improvement in the gas production performance of the tested compartment. Continuing injection is needed to increase the EGR potential of CO2 injection. Further study is needed and GPN has committed itself to continue 
the injection test in 2006.