Mares, T.; Zarrouk, S. 2009 Opportunities for underground geological storage of CO2 in New Zealand : report CCS-08/3a, Waikato coal resource, reservoir modelling. Lower Hutt, N.Z.: GNS Science. GNS Science report 2009/56 88 p.
Abstract: The Waikato coalfields in the North Island of New Zealand are currently being assessed for coalbed methane development. The Eocene coalfields have significant subbituminous coal deposits that contain biogenically-sourced methane. The Huntly coalfield, one of the Waikato coalfields, has previously been characterised to have relatively low to moderate total gas contents (2 - 4 m3/tonne) that are >90% methane (CH4) in composition. The CO2 holding capacity is relatively high (18.0 m3/tonne) compared with that of CH4 (2.6 m3/tonne) and nitrogen (N2) (0.7 m3/tonne) at the same pressure (4 MPa; all as received basis). This study has been conducted to assess the potential of the Waikato coalfields for CO2 sequestration and enhanced coalbed methane (ECBM). Three locations were selected for investigation (1) Ruawaro: a medium depth, moderate-low permeability area with good gas content, (2) Mangapiko: a deep, high permeability area with low gas content, and (3) Ohinewai: a shallow, moderate-low permeability area with very low gas content and thick coal seams. 3D scenarios with a 9-spot well design were conducted using a new module for the TOUGH2.2 reservoir simulator (ECBM-TOUGH2.2) that can handle non-isothermal, multi-phase flows of mixtures of water, CH4, CO2, N2 and H2S. (auth/DG)