An Integrated Study of the CO2 Storage Potential in the Offshore Vlaming Sub-Basin: Results of the study undertaken as part of the NCIP program

As part of the National CO2 Infrastructure Plan (NCIP) between 2011 and 2014 Geoscience Australia undertook a comprehensive study in the offshore Vlaming Sub-basin to provide new pre-competitive data and information to underpin potential CO2 storage solutions. The Vlaming Sub-basin is a Mesozoic depocentre within the southern Perth Basin located about 30 km west of Perth. It covers an area of approximately 23,000 km2 and contains up to 14 km of sediments. The basin lies close to industrial sources of CO2 emissions in the Perth area and contains a number of reservoir-seal pairs potentially suitable for CO2 storage. The Gage Sandstone and the overlying South Perth Shale (SPS) deposited as part of the early post-rift succession are considered the most prospective reservoir-seal pair. Previous assessments of this basin indicated that up 1 GT of CO2 can be stored in the Gage Sandstone reservoir. However, lack of interest in the 2009 Greenhouse Gas acreage release in the Vlaming Sub-basin showed that a more detailed assessment is required.This study addresses critical scientific issues underpinning CO2 storage potential of the Vlaming Sub-basin that were not sufficiently explored previously. These include:-    better characterisation of the reservoir heterogeneity;-    detailed understanding of the seal quality and integrity; -    a more accurate estimate of the practical storage capacity and, -    an accurate environmental baseline and potential issues of environmental concern Overall the study confirmed suitability of the Gage Sandstone reservoir for long-term storage of CO2 and provided a more accurate delineation of the suitable storage sites. At the same time it highlighted the importance of careful consideration of the containment and potential environmental impact in any future CO2 storage projects.

2011至2014年间，作为国家二氧化碳基础设施计划（National CO2 Infrastructure Plan, NCIP）的一部分，澳大利亚地质科学局（Geoscience Australia）在弗拉明次盆地（Vlaming Sub-basin）近海区域开展了一项综合性研究，旨在获取全新的前竞争数据（pre-competitive data）与信息，为潜在的二氧化碳封存解决方案提供支撑。
弗拉明次盆地是珀斯盆地（Perth Basin）南部的中生代沉积中心（depocentre），距珀斯以西约30公里，总面积约23000平方千米，沉积地层最大厚度可达14千米。该盆地毗邻珀斯地区的工业二氧化碳排放源，且发育有多组潜在适宜二氧化碳封存的储盖组合（reservoir-seal pairs）。其中，作为裂谷后沉积序列（post-rift succession）早期组成部分的盖奇砂岩（Gage Sandstone）与上覆的南珀斯页岩（South Perth Shale, SPS），被认为是最具勘探前景的储盖组合。
此前针对该盆地的评估结果显示，盖奇砂岩储层可封存高达1吉吨（GT）的二氧化碳。但2009年弗拉明次盆地温室气体勘探区块出让活动无人问津，表明需要开展更为细致的评估工作。
本研究针对此前未得到充分探明的、支撑弗拉明次盆地二氧化碳封存潜力的关键科学问题展开攻关，具体包括：
- 更精准地刻画储层非均质性（reservoir heterogeneity）；
- 深入理解盖层质量与完整性（seal quality and integrity）；
- 更准确地估算实际封存容量（practical storage capacity）；
- 建立精准的环境基线（environmental baseline）并识别潜在环境关切问题。
总体而言，本研究证实了盖奇砂岩储层具备长期封存二氧化碳的适宜性，并对适宜封存位点（suitable storage sites）进行了更为精准的圈定。同时，研究也强调，在未来任何二氧化碳封存项目中，都需审慎考量储层封闭性与潜在环境影响。