CO 2 INJECTION AT K12-B

Transcription

1 CO 2 INJECTION AT K12-B MONITORING AND MODELLING 2 ND COMBINED MEETING OF THE IEAGHG MODELLING AND MONITORING NETWORKS, EDINBURGH, 2016 Vincent.Vandeweijer@tno.nl & Cor.Hofstee@tno.nl

2 HIGHLIGHTS OF K12-B First site in the world where CO 2 is being injected into the same reservoir from which it originated First and only operational CO 2 storage project in the Netherlands, CO 2 injection started in 2004 Serves as field laboratory on a fully productive gas platform in the Southern North Sea CO 2 injection performed on the mature, still producing natural gas field K12-B 12 years of capturing and re-injection of CO 2 without any major incidents Long term ongoing scientific research Close collaboration between operator and research institutes 2 Monitoring of K12-B

3 AIM OF THE INITIAL CO 2 RE-INJECTION PROJECT To investigate the feasibility of CO 2 injection and storage in a for the Netherlands typical Rotliegend natural gas reservoir The initial feasibility study would address : Legal, regulatory and social aspects Necessary surface and sub-surface equipment Economics of underground injection and storage Expected behaviour of the natural gas field Safety, monitoring and environmental aspects Initial project was performed by Gaz de France and TNO 3 Monitoring of K12-B

4 LOCATION AND SIZE Gas field in the Dutch sector of the North Sea 150 km North West of Amsterdam 8 km long & 2.5 km wide 4 Monitoring of K12-B

5 LOCATION AND SIZE Overlay of the field as reference* 5 Monitoring of K12-B

6 GEOLOGICAL SETTING Gas field in the Upper and Lower Slochteren* Aeolian and fluvial sediments Permian age Zechstein salt seal 3900 m Depth* Compartmentalized 128C Low permeability K12-B6 Upper Slochteren Main reservoir Plug Lower Slochteren 60% water saturation 6 Monitoring of K12-B

7 OVERVIEW OF THE CO 2 INJECTION FACILITIES The CO 2 is separated from the natural gas by means of an adsorption process with a solvent A compression unit compresses the CO 2 to approximately reservoir pressure to enable injection Full-scale unit would be about 10 to 20 times larger than that of the current demonstration unit 7 Monitoring of K12-B

8 CO 2 INJECTION AT K12-B K12-B8 Injector/Producer All wells were originally developed as natural gas producers In 2004 actual CO 2 injection started in single well compartment 4* Investigate injectivity and test the injection facility Investigate the behavior of CO 2 in the well and the reservoir Over 10 kt were injected using the K12-B8 well Injection continued in 2005 in multi well compartment 3*, additional goals: Investigative well integrity under CO 2 injection conditions* Investigate possibilities for CO 2 EGR Over 100 kt CO 2 re-injected and counting K12-B3st1 - Producer K12-B5 - Producer K12-B1 - Producer K12-B6 Injector 8 Monitoring of K12-B

9 DYNAMIC FLOW MODELS History matched cellular models for pressure and flow were created* Later also CO 2 concentrations in production wells were modelled* Various simulators where used and numerous updates were created B1 CO2 prod. Sim. B1 CO2 prod. Obs. 23 CO2 production B1 [mass %] Monitoring of K12-B Time [days]

10 BACK PRODUCTION INJECTED CO 2 Well K12-B8 is a gas producer that stopped producing mid This well was used end 2004 and early 2005 for the first phase of CO 2 injection in the K12-B field (10 months of CO 2 injection)*. The figure shows the predicted reservoir pressure rises slightly during the suspended state of the B8 producer. This rise in pressure can be attributed to the low transmissivity of faults, which allows for continuous and gradual drainage of natural to the lower pressure adjacent sub-compartment.* 10 Monitoring of K12-B

11 BACK PRODUCTION INJECTED CO 2 The well was back produced in 2007 after leaving the re-injected CO 2 untouched for three years in the reservoir.* Measurements were taken (incl. CO 2 concentration), providing insights in the behavior of CO 2 in the depleted gas reservoir. The experiment was repeated in Monitoring of K12-B

12 BACK PRODUCTION INJECTED CO 2 According to simulations the re-injected CO 2 would stay rather close to the injector. Simulation results, right after the second back production period, indicate even higher CO 2 concentrations near the injector / producer 12 Monitoring of K12-B

13 BACK PRODUCTION INJECTED CO 2 The simulator calculated higher CO 2 concentrations than measured and also a different curve / development of the concentration through time.* This means that the actual transport and fate of the CO 2 in the reservoir is not completely described correct by the simulator. We expect this to be caused by a more distinct spreading and dispersion of the CO 2 in reality than what is calculated by the simulator. This is being investigated under the EU Mirecol project. 13 Monitoring of K12-B

14 CHEMICAL TRACERS Objective: study the migration and the retardation effect of CO 2 and CH 4 in the reservoir K12-B3st1 - Producer Initially 2 chemical tracers were injected in the K12-B6 well at start of CO 2 injection in 2005 Tracer concentration was measured in the 2 (3) producers to identify exact breakthrough* K12-B5 - Producer K12-B1 - Producer K12-B1 K12-B5 5E E Tracer Concentration (L/L) 4,5E-10 4E-10 3,5E-10 3E-10 2,5E-10 2E-10 1,5E-10 1E-10 PMCP 1,3-PDMCH CO2 fraction CO2 fraction (%) Tracer Concentration (L/L) 4,5E-10 4E-10 3,5E-10 3E-10 2,5E-10 2E-10 1,5E-10 1E-10 PMCP 1,3-PDMCH CO2 fraction K12-B6 Injector CO2 fraction (%) 5E E Monitoring of K12-B

15 CHEMICAL TRACERS Last month (June 2016) new chemical tracers were injected in K12-B6 Tracers where designed together with CSIRO (Australia) The tracers are expected to migrate at different velocities through the reservoir Objective is roughly the same as the initial test, but we now also have tracers to mimic CO 2 * 15 Monitoring of K12-B

16 CHEMICAL TRACERS Already the use of tracers has contributed to an improved understanding of how the CO 2 migrates through the reservoir and the general potential for CO 2 enhanced gas recovery. Current project on new chemical tracers is expected to further improve the general understanding of CO 2 injection in nearly depleted gas fields 16 Monitoring of K12-B

17 OUTLOOK Actual detection at production wells of the new innovative tracers Experiment to restore the original natural salt seal by removal of part of the casing 17 Monitoring of K12-B

18 THANK YOU FOR YOUR ATTENTION