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洞穴。该项目集合了地质学家、地球工程师和数学家的专业知识，通过实验和计算研究了0.1到100米范围内溶质在洞穴岩石中的流动和传输。对得克萨斯州中部的管道溪礁露头进行的实验研究将进行：(1)在实验室对小于10-20厘米的样品进行测定，以确定岩洞的性质和微尺度的示踪剂传输特征；(2)在超过1-10米的尺度上确定有效渗透率和示踪剂注入响应；(3)在野外使用地质穿透雷达绘制超过1-100米的大尺度地质地图。这些数据将被用来构建详细亚厘米尺度的输运过程的微观模型和代表该系统的宏观模型，包括其在至少1-100米尺度上的结构上的洞穴互联、时间尺度和宏观分散。有效和准确的计算实施将允许进行测试和验证。统计分析将量化数据中的不确定性，以便在全实地范围内使用。该项目预计将大大改进宏观尺度上洞穴介质中流动和传输的模拟，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奠定坚实的经验基础。该项目将有助于对类似的多孔介质，如岩溶和裂隙系统，以及更广泛地说，相关的多尺度系统的模拟。该项目将影响三名博士生，并加强两个面向工业界的外展项目，即油藏特征研究实验室(RCRL)和地下建模中心(CSM)。最后，由于碳酸盐岩包括世界上许多含水层和储油层，随着进步允许更有效地保护地下水供应和石油生产，社会将受益。一些碳酸盐岩层含有被称为洞穴的洞穴，大约几厘米大小。流体在这些洞穴中的流动比在岩石本身中(即在岩石颗粒之间)容易得多。化学物质的迁移，如地下水污染物，受到这些洞穴的性质的强烈影响。在相互连接的洞穴路径中，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，目前对流体如何在如此多洞穴的岩石中长距离流动知之甚少。这个项目联合了地质学家、地球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，以确定超过10-20厘米的小洞穴中的流体流动行为，以及长达10米的洞穴通道内的流体流动行为。探地雷达将用于绘制超过1-100米比例尺的大比例尺地质地图。利用这些数据，将建立两个模型，即计算机模拟代码。第一个模型将描述亚厘米尺度的详细流动。第二种方法将仅在平均意义上描述流量，以便在整个含水层或油气藏的现场范围内有意义地使用。此外，统计分析将允许对数据中的不确定性进行量化。预计该项目将大大改进大尺度洞穴介质中流动和传输的建模。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。由于碳酸盐岩包括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、可预测和经济有效的补救或遏制策略的工程设计来补救或预防。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.