Multi-Physics Models for Proppant Placement in Energy Georeservoirs

能源地质储层支撑剂放置的多物理模型

• 批准号: 1563614
• 负责人: Ingrid Tomac
• 金额: $ 35.44万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-15 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1563614&HistoricalAwards=false
• 关键词: Multi; Physics; Models; Proppant; Placement

Underground energy technologies are of crucial importance in contemporary geomechanics, including Enhanced Geothermal Systems (EGS). EGS use geothermal energy to produce electricity from hot deep underground permeability-enhanced rock formations. This project addresses the need for more effective proppant (granular material that keeps the fractures open) usage during geothermal energy recovery. Specifically, resolving proppant placement issues will aid optimization, growth and further development of georeservoirs, and will speed up transformation of the EGS technology from its current early development stage to commercial use. This will benefit global renewable energy market and global sustainable energy delivery. This research has also a potential for contributing to quantitative understanding of several additional geomechanical issues, such as mud flows and slurry flows, internal erosion of dams and scouring of soil around structures. This research project advances the knowledge of fundamental physics of flow of dense suspensions, and develops new theories that would improve engineering design for proppant placement into branching hydraulic fractures with irregular, rough surfaces. The models resulting from this activity will, for the first time, capture particle agglomeration by accounting for the interplay between particle-particle interactions and fluid hydrodynamic forces and the role of fluid, particle and fracture properties. Our multidisciplinary team, consisting of a geotechnical engineer and a mathematical modeler, will collaborate with other programs to broaden participation of women and other underrepresented groups in science through research, engineering and educational engagements.This project seeks to better understand and mitigate the conditions resulting in proppant logging during proppant-fluid injection into hydraulic fractures. The project products will lead to efficient proppant placement during permeability enhancement, potentially reducing its environmental impact. The overarching goal of this project is to gain quantitative understanding of this phenomenon and requires development of new mathematical theories. Current practice for predicting proppant flow and transport relies on empirical relationships developed from laboratory tests involving large width, smooth, straight slots, appropriate for use in simplified single-fracture models. However, most hydraulic fractures are rough and branching, which creates a complex path for the fluid and proppant transport. The physics of dense slurry flow and transport includes particle-particle and fluid-particle interactions. Especially for fluids used in proppant placement, this physics is not properly understood and, hence, not adequately accounted for in current models. A mathematical model of proppant flow in realistic fracture networks will be developed, and validated with laboratory-scale experiments. The experimental component comprises next-generation slot-flow experiments in 3-D printed fractures using scanned rock surfaces from fracturing tests. The fractures will be printed with transparent materials, enabling the use of Particle Image Velocimetry (PIV) to track the movement of proppant particles. The project's theoretical part consists of two interrelated components, development of a continuum-scale constitutive law that accounts for particle-particle and particle-fluid interactions, and development of a computationally efficient algorithm for modeling proppant flow in fractures with rough walls and (randomly) varying apertures. The continuum-scale models will be parameterized with parameters reflecting properties of fracture surface's roughness, average fracture width, and physical and mechanical properties of fluid and proppant particles. These and other effective model parameters will be determined from both discrete numerical simulations and slot-flow experiments. The model will serve as a practical tool for reservoir engineers to ensure the proper proppant placement in hydraulic fractures and to predict and plan the reliable permeability enhancement of georeservoirs.

地下能源技术在当代地质力学中至关重要，包括增强的地热系统（EGS）。例如，使用地热能从热深地下渗透性增强的岩层中产生电力。该项目解决了在地热能恢复期间对使用更有效的支撑剂（使骨折开放的颗粒状材料）的需求。具体而言，解决撑杆的放置问题将有助于优化，增长和地球群的进一步发展，并将加快EGS技术从其当前的早期开发阶段到商业用途的转型。 这将受益于全球可再生能源市场和全球可持续能源交付。这项研究还具有有助于定量理解几个其他地质力学问题的潜力，例如泥浆和泥浆流，大坝的内部侵蚀以及围绕结构周围的土壤搜查。该研究项目促进了密集悬浮液流动的基本物理学的知识，并开发了新的理论，这些理论将改善工程设计，以将其放置在分支的液压裂缝中，并具有不规则，粗糙的表面。该活性产生的模型将首次通过考虑粒子粒子相互作用与流体流体动力学之间的相互作用以及流体，颗粒和断裂特性的作用来捕获粒子团聚。我们的多学科团队由岩土工程师和数学建模者组成，将与其他计划合作，通过研究，工程和教育参与来扩大妇女和其他代表性不足的科学团体的参与。该项目旨在更好地理解和缓解在Proppant-Fluilfluid-fluilfluid Insection fymection hymercection hymeric fracection hymeric fracection froff fricction fracection frofcection frof fracection hymeric fracection hymeric fracection。该项目产品将在渗透性增强过程中导致有效的支撑剂放置，从而有可能降低其环境影响。该项目的总体目标是获得对这一现象的定量理解，并需要开发新的数学理论。当前预测支撑剂流量和运输的实践取决于涉及大宽度，光滑，直插槽的实验室测试发展的经验关系，适用于简化的单裂纹模型。但是，大多数液压裂缝都是粗糙和分支的，这为流体和支撑剂转运创造了复杂的路径。致密的浆液流和传输的物理学包括粒子粒子和流体粒子相互作用。尤其是对于用于支撑剂放置的流体，这种物理学尚未正确理解，因此在当前模型中没有充分考虑。将开发现实断裂网络中支撑剂流的数学模型，并通过实验室规模实验进行验证。实验组件包括使用断裂测试的扫描岩石表面进行3D打印裂缝中的下一代插槽实验。裂缝将用透明的材料打印，从而可以使用粒子图像速度法（PIV）来跟踪支撑剂颗粒的运动。该项目的理论部分由两个相互关联的组成部分组成，即构成粒子粒子和粒子流体相互作用的连续尺度构型法律，以及开发用于建模用于与粗糙壁和（随机）varying partures裂缝中的预言流量的计算有效算法。连续尺度模型将用参数化，以反映断裂表面粗糙度，平均断裂宽度以及流体和支撑剂颗粒的物理和机械性能的特性。这些和其他有效的模型参数将由离散数值模拟和插槽流实验确定。该模型将作为储层工程师确保在液压裂缝中适当放置的储层工程师的实用工具，并预测和计划可靠的渗透性增强地层地层。