CMG Research: Multi-scale Flow and Transport Modeling of Large-vug Cretaceous Carbonates

一些碳酸盐地层含有几厘米大小的洞穴或空洞。这个项目联合了地质学家、地质工程师和数学家的专业知识，通过实验和计算研究溶质在洞穴岩石中0.1到100米距离内的流动和运输。对德克萨斯州中部的管道溪礁露头进行实验研究：(1)在实验室对10-20厘米尺度下的样品进行测试，以确定岩石和空隙的性质以及微尺度示踪剂的运输特征；(2)在1-10 m范围内确定有效渗透率和示踪剂注入响应；(3)利用探地雷达在野外进行1 ~ 100 m尺度以上的大比例尺地质制图。这些数据将用于在详细的子尺度上构建输运过程的微观尺度模型和代表系统的宏观尺度模型，包括其拓扑空洞互联性，时间尺度和至少1-100米尺度上的宏观分散。高效和准确的计算实现将允许测试和验证。统计分析将量化数据的不确定性，以便在整个现场尺度上使用。该项目预计将在宏观尺度上对溶洞介质的流动和输运建模进行实质性的改进，为宏观尺度模型中有效参数的选择和参数不确定性的处理提供坚实的经验基础。它应该启发类似的多孔介质的建模，如岩溶和裂缝系统，以及更一般地，相关的多尺度系统。该项目将影响三名博士生，并加强与工业界的两个外展，油藏表征研究实验室（RCRL）和地下建模中心（CSM）。最后，由于碳酸盐岩构成了世界上许多的含水层和油藏，社会将受益于技术进步使地下水供应和石油生产得到更有效的保护。一些碳酸盐岩地层含有几厘米大小的洞穴，称为洞穴。流体在这些洞穴中比在岩石内部（即岩石颗粒之间）更容易流动。化学物质的输送，如地下水污染物，受到这些洞穴性质的强烈影响。在一个相互连接的孔洞路径中，污染物可以相当快地流动，但当它重新进入岩石时，它必须相当慢。然而，目前对于流体如何在这样的洞穴岩石中长距离流动知之甚少。这个项目联合了地质学家、地质工程师和数学家的专业知识来解决这个问题。将进行实验研究，以确定流体在10-20厘米以上的小洞穴中的流动行为，以及在长达10米的洞穴通道内。地面穿透雷达将用于绘制1-100米尺度以上的大比例尺地质。利用这些数据，将构建两个模型或计算机模拟代码。第一个模型将详细描述亚厘米尺度的流动。第二种方法将仅在平均意义上描述流体，因此它可以在整个含水层或油藏的现场尺度上有意义地使用。此外，统计分析将允许对数据中的不确定性进行量化。该项目预计将大大改进大型溶洞介质的流动和输送模型。该项目将影响三名博士生的教育，他们将在跨学科的环境中接受培训。由于碳酸盐岩构成了世界上许多含水层和油藏，社会将间接受益。地下模拟是一种重要的工程工具。地下水污染可以通过有效的、可预测的、成本有效的修复或遏制策略的工程设计来修复或预防。基于模拟研究的工程分析也用于量化、管理和降低与油藏管理相关的风险。

Some carbonate strata contain vugs or cavities about the size of a fewcentimeters. This project unites the expertise of geologists, geo-engineers,and mathematicians to study experimentally and computationally the flow andtransport of solutes in vuggy rocks over distances of 0.1 to 100 meters.Experimental studies of the Pipe Creek Reef outcrop in Central Texas will bemade: (1) in the laboratory on samples at the sub 10-20 cm scale to determinerock and vug properties and micro-scale tracer transport characteristics; (2)in the field over 1-10 m scales to determine effective permeabilities andtracer injection response; and (3) in the field using ground penetrating radarto map the large scale geology over 1-100 m scales. The data will be used toconstruct a micro-scale model of the transport process at the detailed sub-cmscale and a macro-scale model to represent the system, including itstopological vug interconnectivity, time-scales, and macro-dispersion on scalesof at least 1-100 m. Efficient and accurate computational implementation willallow testing and verification. Statistical analysis will quantify uncertaintyin the data for use at full field scales. The project is expected to result insubstantially improved modeling of flow and transport in vuggy media over themacro-scale, with a solid empirical basis for the selection of the effectiveparameters in the macro-scale model, and the handling of parameter uncertainty.It should illuminate modeling of similar porous media, such as karsts andfractured systems, and, more generally, related multi-scale systems. Theproject will impact three Ph.D. students and enhance two outreaches to theindustrial community, the the Reservoir Characterization Research Laboratory(RCRL) and the Center for Subsurface Modeling (CSM). Finally, since carbonaterocks comprise many of the world's aquifers and oil reservoirs, society willbenefit as progress allows more effective protection of groundwater suppliesand production of petroleum.Some carbonate rock strata contain cavities, called vugs, about the size of afew centimeters. Fluid can flow much more easily in these vugs than within therock itself (i.e., between the rock grains). The transport of chemicalspecies, such as groundwater contaminants, is strongly influenced by the natureof these vugs. Within an inter-connected vug path, the contaminant can flowquite rapidly, but it must slow considerably when it re-enters the rock.However, little is currently known about how fluid flows in such vuggy rocksover long distances. This project unites the expertise of geologists,geo-engineers, and mathematicians to address the problem. Experimental studieswill be made to determine the behavior of fluid flow in small vugs over 10-20centimeters, and within vug channels up to 10 meters long. Ground penetratingradar will be used to map the large scale geology over 1-100 meter scales.Using this data, two models, or computer simulation codes, will be constructed.The first model will describe the flow at the detailed sub-cm scale. Thesecond will describe the flow only in an average sense, so that it can be usedmeaningfully at the field scale of an entire aquifer or petroleum reservoir.Moreover, statistical analysis will allow for the quantification of uncertaintyin the data. The project is expected to result in substantially improvedmodeling of flow and transport in vuggy media over large scales. The projectwill impact the education of three Ph.D. students, who will be trained in aninterdisciplinary environment. Since carbonate rocks comprise many of theworld's aquifers and oil reservoirs, society will benefit indirectly.Subsurface simulation is an important engineering tool. Groundwatercontamination can be remediated or prevented through the engineering design ofvalid, predictable, and cost effective remediation or containment strategies.Engineering analysis based on simulation studies is also used to quantify,manage, and reduce risks related to oil reservoir management.