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Unstructured Grid Simulation of Hydromechanical Effects in Fractured Reservoir during CO2 Sequestration

UKCCS Community NetworkEarly Career Researcher Winter School8th - 11th February 2011Imperial College London

Robert AnnewandterECOSSE PhD-Candidate

Prof Sebastian Geiger Institute of Petroleum EngineeringHeriot-Watt University

Prof Ian Main School of GeoSciences University of Edinburgh

Aftershocks Driven by a High-Pressure CO2

(Miller et al., Nature, 2004)

2 Earthquakes (M = 5.7 and 6) in 1997 in northern Italy w/ 1000 aftershocks for about 30 days

Sequence driven by fluid presssure pulse generated from coseismic release of trapped CO2

Pressure Built-Up Impacts Huge Area

(Birkholzer and Zhou et al., IJGGC, 2009)

Post-Glacial Lithospheric Flexure Affects Pore Pressure and In-Situ Stress Field

(Grollimund and Zoback, Tectonophysics, 2000)

Fluid Rock Coupling

Research Objectives

Complex System Modeling Platform and Fracture Networks

Miscible Compressible Multicomponent-Multiphase Flow and Transport

Outlook - Coupled Flow and Geomechanics

Structure of Presentation

Fluid Rock Coupling 101

(Rutqvist and Stephanson, Hydrogeol. J., 2009)

Fault zone activation

Fracture Opening

– Conditions for Fault Activation– Maximum Sustainable Injection Pressure– Post-Glacial Rebound Effect– Response of Pre-existing Fractures– Influence of Regional Stress Field - Far Stress

Field on Aquifer’s Storage Potential– Generic North Sea Case with Sensitivity Study

Research Objectives

Pressure Velocity magnitude

Fractured sandstone from Norway (CSMP Flow Simulation)

CSMP and Fracture Networks

(Fracture Model: Odling, J. Struct. Geol., 1997)

Why Another Simulator?

small change in fracture aperture will have a tremendous impact on the flow behaviour!

Birds-eye view of fracture patterns in chalk mapped at Kilve Beach in the Bristol Channel, U.K.

Fracture Aperture a = 0.01 mm

Fracture Aperture a = 0.03 mm

Fracture Aperture a = 1.00 mm

We Need an Equation of State!

(Mathias et al., IJGGC, 2009)

Miscible Compressible Multicomponent Multiphase Flow and Transport

Outlook - Coupled Flow and Geomechanics

Fixed stress-splitUnconditional stable regardless of couple strengthMore accurate for given numbers of iteration

(Kim et al., SPE Reservoir Simulation Symposium, 2009)

Wrap up

1. Large scale pressure built-ups can extent to several hundred kilometres affecting fault zones with in

2. Fluid pressure induced stress changes impacts fracture aperture and therefore affects flow pattern massively

3. Nonlinear flow and transport physics has to be implemented which has not been done comprehensively

4. CSMP can simulate flow and transport problems for a structural complex geology in great detail by means of FEFV on hybrid meshes and CTRW upscaling techniques

Cheers!

Funded by Scottish Carbon Capture & Storage

robert.annewandter@pet.hw.ac.uk