Modelling CO2 EOR-storage in Residual Oil Zones

Geoscience Australia and CSIRO have collaborated, under the Exploring for the Future program, to investigate whether water-saturated residual oil zones (ROZs), sometimes associated with conventional Australian hydrocarbon plays, could provide a CO2 storage resource and enhance the storage capacity of depleted fields. This product is part of a larger project that includes, among others, a petrophysical study to identify and characterise ROZs. In this report, we model the formation of a residual oil zone in an Australian setting and the subsequent injection of CO2 using a 5 spot well pattern. The reservoir is built as an archetype example of the Hutton Formation from the Cooper-Eromanga basin. The reservoir interval is populated with "permeable sandstone” and “impermeable baffle” facies and a sealing layer at the top of the model is created and assigned properties such that it can be made to leak oil by capillary failure, as part of the process used to create a residual oil column. The static model is them imported into CMG-GEM software for the reservoir flow simulations. We find the scenario, with injectors perforated at the top and a central producing well perforated at the bottom, able to both store the most CO2 and produce the most oil. The storage and sweep efficiencies are high, highlighting the difference with typical CO2 storage scenarios without pressure mitigation.For more information about this project and to access the related studies and products, see: https://www.eftf.ga.gov.au/carbon-co2-storage-residual-oil-zones. Data is available on request from [e-mail] - Quote eCat# 149366

澳大利亚地质调查局（Geoscience Australia）与澳大利亚联邦科学与工业研究组织（CSIRO）在“未来勘探”（Exploring for the Future）项目框架下开展合作，旨在探究与澳大利亚常规油气藏相关的含水残余油带（residual oil zones, ROZs）能否作为二氧化碳（CO₂）封存资源，并提升枯竭油气田的封存容量。本数据集是一项大型研究项目的组成部分，该项目涵盖多项研究内容，其中包括用于识别与表征残余油带的岩石物理研究。本报告针对澳大利亚区域的残余油带形成过程，以及采用五点法井网（5 spot well pattern）注入二氧化碳的过程开展数值模拟。该储层原型取自库珀-厄罗曼加盆地（Cooper-Eromanga basin）的赫顿组（Hutton Formation）。储层段发育“渗透性砂岩”与“非渗透性隔层”两种沉积相，并在模型顶部构建密封层，通过设置相关物性使其可通过毛细管突破发生溢油，以此形成残余油柱。随后将构建完成的静态模型导入CMG-GEM软件中开展油藏流动模拟。研究发现，采用顶部射孔注入井与底部射孔中心生产井的部署方案，可实现最高的二氧化碳封存量与原油采出量。该方案的封存效率与波及效率均处于较高水平，凸显了其与常规无压力缓解措施的二氧化碳封存场景的显著差异。如需了解该项目更多信息，获取相关研究成果与数据集，请访问：https://www.eftf.ga.gov.au/carbon-co2-storage-residual-oil-zones。相关数据可通过邮箱[e-mail]申请获取，请标注编号eCat# 149366。