Predicting Physical Properties of Fluid-Containing Rocks from Percolation Model Results

[409279][王]侵入的液体或气体置换水的物理学是一个重要的地质和工程过程。例子包括石油或天然气向含盐水饱和岩石的运移，或通过注入空气修复受污染的含水层。由于孔隙结构的随机性及其对毛细力的影响，侵入流体的分布可能包括复杂的指动。一种成功的模拟侵入空气的方法是通过孔隙尺度，改进的侵入渗透模型，其中岩石的空隙空间由孔隙和喉道尺寸的统计分布表示。每个毛孔都连接着几个喉部。被侵入的空气-水界面上的喉部是驱动势（重力、毛细管力和粘性力总和）最大的喉部。该项目的科学目标是将渗流模型得到的流体相分布联系起来，预测整体岩层的弹性和电性。提出的创新是在孔隙尺度上使用基于过程的流体饱和度量化作为预测对流体分布极其敏感的物理性质的基础。这些预测对于通过地球物理测量推断流体饱和度具有重要意义。工作假设是，防御水簇的大小分布对体弹性行为至关重要。小的、孤立的水团表现出一种弹性柔软的方式，因为水能够流入附近充满空气的空隙。提出了蒸发干燥过程中弹性波速的新实验室测量方法。他们和最近在路易斯安那州立大学进行的蒸发干燥过程中的电阻率测量将用于校准和测试建模过程。本研究在油气勘探和污染含水层监测修复等方面具有广泛的应用前景。这项研究将提供关键的岩石实验室测量和建模工具，以模拟空气或气体对水的位移，然后预测地球物理性质的变化。收集到的关于蒸发干燥过程中弹性波速变化的新数据将对其他研究人员测试他们的模型有用。研究结果将通过出版物和口头报告传播。作为研究的一部分，将开发的计算机代码将对工业研究人员有用，并将在互联网上提供。

0409279WangThe physics of displacement of water by an invading liquid or gas is an importantgeologic and engineering process. Examples include the migration of oil or gas intobrine-saturated rock or remediation of contaminated aquifers by injection of air. Thedistribution of the invading fluid can include intricate fingering due to the inherentrandomness of the pore structure and its influence on capillary forces. A successfulmethod to simulate the invading air is through a pore-scale, modified invasionpercolation model in which the rock's void space is represented by a statisticaldistribution of pore and throat sizes. Each pore is connected to several throats. Thethroat on the air-water interface that is invaded is the one at which the driving potentialsumming gravity, capillary, and viscous forces is greatest. The scientific goal of thisproject is to connect the distribution of the fluid phases obtained from the percolationmodel to predict the elastic and electrical properties of the bulk rock formation. Theinnovation proposed is to use a process-based quantification of fluid saturation at the porescale as the basis for predicting physical properties that are extremely sensitive to thefluid distribution. These predictions are important for inferring the fluid saturations fromgeophysical measurements. The working hypothesis is that the size distribution of thedefending water clusters is critical to the bulk elastic behavior. Small, isolated waterclusters behave in an elastically soft manner because the water is able to flow into nearbyair-filled voids. New laboratory measurements of elastic wave velocities duringevaporative drying are proposed. They and recent electrical resistivity measurementsduring evaporative drying conducted at Louisiana State University will be used tocalibrate and test the modeling process.Broader ImpactsThis research is expected have applications in exploring hydrocarbon reservoirs and inmonitoring remediation of contaminated aquifers. This research will provide key rocklaboratory measurements and modeling tools to simulate the displacement of water by airor gas and then predict the changes in geophysical properties. New data collected onchanges of elastic wave velocities during evaporative drying will be useful to otherresearchers testing their models. The research results will be disseminated throughpublications and oral presentations. The computer codes that will be developed as part ofthe research will be useful to researchers in industry and will be made available on theinternet.