Geoscience Australia and Geological Survey of Queensland Surat and Bowen Basins Groundwater Surveys Hydrochemistry Dataset (2009-2011)

Recent national and state assessments have concluded that sedimentary formations that underlie or are within the Great Artesian Basin (GAB) may be suitable for the storage of greenhouse gases. These same formations contain methane and naturally generated carbon dioxide that has been trapped for millions of years. The Queensland government has released exploration permits for Greenhouse Gas Storage in the Bowen and Surat basins. An important consideration in assessing the potential economic, environmental, health and safety risks of such projects is the potential impact CO2 migrating out of storage reservoirs could have on overlying groundwater resources. The risk and impact of CO2 migrating from a greenhouse gas storage reservoir into groundwater cannot be objectively assessed without knowledge of the natural baseline characteristics of the groundwater within these systems. Due to the phase behaviour of CO2, geological storage of carbon dioxide in the supercritical state requires depths greater than 800m, but there are no hydrochemical studies of such deeper aquifers in the prospective storage areas. Geoscience Australia (GA) and the Geological Survey of Queensland (GSQ), Queensland Department of Mines and Energy, worked collaboratively under the National Geoscience Agreement (NGA) to characterise the regional hydrochemistry of the Denison Trough and Surat Basin and trialled different groundwater monitoring strategies. The output from this Project constitutes part of a regional baseline reference set for future site-specific and semi-regional monitoring and verification programmes conducted by geological storage proponents. The dataset provides a reference of hydrochemistry for future competing resource users.

近期国家及州级评估结果显示，大自流盆地（Great Artesian Basin, GAB）下方或内部的沉积地层或可用于温室气体存储。此类地层同时赋存甲烷与天然生成、已被封存百万年的二氧化碳。昆士兰州政府已为鲍恩盆地与苏拉特盆地的温室气体存储（Greenhouse Gas Storage）项目发放勘探许可。

在评估此类项目的潜在经济、环境、健康与安全风险时，一项关键考量因素是二氧化碳自储层运移后对上覆地下水资源可能产生的影响。若不掌握这些系统内地下水的天然本底特征，便无法客观评估温室气体存储储层中的二氧化碳运移至地下水所带来的风险与影响。鉴于二氧化碳的相态特性，超临界状态（supercritical state）二氧化碳的地质存储要求埋藏深度超过800米，但目前针对潜在存储区内此类深部含水层的水化学（hydrochemistry）研究仍属空白。

澳大利亚地质调查局（Geoscience Australia, GA）与昆士兰州矿产与能源部下属的昆士兰州地质调查局（Geological Survey of Queensland, GSQ）依托《国家地质科学协议》（National Geoscience Agreement, NGA）开展合作，对丹尼森槽地与苏拉特盆地的区域水化学特征开展表征研究，并试验了多种地下水监测方案。本项目产出成果可作为区域本底参考数据集的组成部分，供未来地质存储项目方开展针对具体场地及半区域的监测与验证工作使用。本数据集可为未来存在资源竞争关系的各类用户提供水化学参考依据。