Extraction of Formation Water from CO₂ Storage

Publication Overview

The main aim of the study would be to assess the global potential for extraction of formation waters as part of DSF storage projects. The study would comprise a comprehensive literature review, from published research and industrial analogues (e.g. brine disposal from petroleum and coal bed methane industries) to provide guidance on the following issues:

• Potential rates of brine extraction required for varying injection rates, across a typical range of DSF storage scenarios;
• Likely range in chemical composition of extracted brines;
• Options for disposal of brine, either surface or subsurface, and associated potential environmental impacts;
• Onshore and offshore considerations, including treatment required for different disposal options.
• Potential for utilisation of extracted brines, e.g. cooling water for power stations, geothermal energy, and assessment of associated environmental impacts;
• Potential for surface dissolution of CO₂ in extracted brine and re-injection into storage formations;
• Regulatory constraints, including for monitoring requirements, potential liability and water quality requirements for different uses.
• Potential economic implications for CO₂ storage of brine extraction and the various options for disposal/utilisation, to be illustrated by selected case studies.

Publication Summary

The approach taken in this report was to consider case studies with a wide range of geological, geographical and geopolitical conditions, which may impact the ability to implement an extracted water plan in conjunction with commercial scale storage projects. Relatively simple 3-D models were formed to test different injection and extraction scenarios and incorporate vital, heterogeneous reservoir properties, including structure, porosity, permeability, water quality, lithology, temperature, and pressure, which were obtained from published sources. When published data were insufficient to capture expected heterogeneity or did not appear in the literature, variogram ranges and property values were obtained from the revised AGD (Average Global database), which is comprised of information from hydrocarbon reservoir properties as a proxy for DSF characteristics. The AGD was compiled through use of existing US databases and an extensive literature review for other regions (IEAGHG, 2009).