Predicting the fate of CO2 in geological reservoirs for modelling geological carbon storage

本提案的主要目标是确定富二氧化碳盐水和岩石之间流体-岩石相互作用的性质和动力学，在现场环境和实验室实验中，以便制定和测试注入地质地层的二氧化碳的行为和命运模型。要做到这一点，我们需要确定调节流体-矿物反应动力学的过程，特别是与实验室实验预测相比，在现场设置中导致动力学更缓慢的过程的性质。最终目标是建立一个数据库和方法，使这项研究的结果能够用于地质碳储存地点的风险评估和性能建模。为了实现这些主要目标，我们将需要开展以下工作：1)评估天然（二氧化碳天然气储层）和人为（二氧化碳注入EOR -提高采收率）地点作为地质二氧化碳储存的类似物。如有必要，利用一系列矿物学、地球化学和同位素分析技术，确定这些地点的水文和二氧化碳流体与储层盐水相互作用的性质，并描述储层矿物学、可能控制反应速率的矿物特征（例如矿物表面积和拓扑结构）和流体-矿物反应。2)开展储层物质、盖层和单一矿物的室内实验，研究受控条件下的矿液反应和反应动力学，并对现场研究推断的反应和反应动力学进行检验。3)进行实验室实验，详细测量稀有气体在超临界和液态CO2和盐水中的溶解度和分配，并将可用于天然类似物的数据扩展到包括高精度的稀有气体同位素和浓度数据。这些数据将为建立天然铝储层的水文模型提供信息。4)利用现有的和发展改进的平衡和动力学速率有限的矿物-流体反应的热力学模型，以a)将现场和实验室实验的结果联系起来，b)使本研究和其他研究的结果更普遍地应用于特定的现场，c)使用实验室和现场结果来测试广泛使用的矿物反应速率热力学模型的适用性。

The main objective of this proposal is to determining the nature and kinetics of fluid-rock interactions between CO2-rich brines and rocks, in field settings as well as in laboratory experiments, in order to formulate and test models of the behaviour and fate of CO2 injected in geological strata. To do this we need to determine the processes which moderate the fluid-mineral reaction kinetics, particularly the nature of the processes which result in much more sluggish kinetics in field settings compared with the predictions from laboratory experiments. The ultimate objective is to creat a database and methodology that enables the results of this study to be used in risk assessments and performance modelling of geological carbon storage sites. To achieve these main objectives we will need to carry out the following: 1) Evaluate natural (CO2 natural gas reservoirs) and anthropogenic (CO2 injection EOR - Enhanced Oil Recovery) sites as analogues for geological CO2 storage. As necessary, determine the hydrology and the nature of the CO2-fluid to reservoir brine interactions in these sites and characterise the reservoir mineralogy, mineral characteristics that might control reaction rates (e.g. mineral surface areas and topologies) and fluid-mineral reactions by using a range of mineralogical, geochemical and isotopic analytical techniques. 2) Carry out laboratory experiments on reservoir materials, cap rocks and single minerals to investigate mineral-fluid reactions and reaction kinetics under controlled conditions and to test the reactions and reaction kinetics inferred from the field-scale studies. 3) Perform laboratory experiments to make detailed measurements of noble gas solubility in, and partitioning between, supercritical and liquid CO2 and brine and extend the data available for the natural analogues to include high precision noble-gas isotopic and concentration data. This data will inform modelling of the hydrology of the naturalCO2 reservoirs. 4) Utilise existing and develop improved thermodynamic modelling of both equilibrium and kinetically-rate limited mineral-fluid reactions to a) relate the results of field-based and laboratory experiments, b) enable more general application of the results from this and other studies to specific field sites and c) use the laboratory and field results to test the applicability of widely used thermodynamic models for mineral reaction rates.