Coupled Geomechanics Processes

耦合地质力学过程

• 批准号: RGPIN-2016-04475
• 负责人: Dusseault, Maurice
• 金额: $ 1.97万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=615086
• 关键词: Coupled; Geomechanics; Processes

Reliable decarbonized energy for Canada's future requires C-free sources and grid-scale storage. The two grid-scale storage options that can incorporate stochastic renewables (wind, solar) are pumped hydro and compressed air geostorage (CAES). I will develop thinly bedded salt cavern CAES in Canada, using long galleries to attain suitable volumes (e.g. 20x30x750 m). Provinces that can benefit from this approach, coincidentally, are those that have little pumped hydro potential (AB, SK, ON, NB, NS)! Novel ideas for consistent solutioning of thin-bed salt galleries are needed (horizontal wells , sliding sleeve and port methods), as well as analysis and design methods to optimize span choice and gallery array spacing. Roof rocks tend to be horizontally stratified non-salt rocks that can delaminate and slough when exposed to numerous pressurization cycles, and material behavior laws needed for this type of analysis have to be clarified and incorporated into the calculation procedure. The entry of air into partially delaminated roof strata, followed by the pressure loads during depressurization, leads to roof deterioration and potential large-scale sloughing which can impair cavern integrity if overburden conditions are unfavorable. Combining the viscous salt response with the elasto-plastic response of the roof through thousands of pressure cycles is a computationally demanding exercise. My students will also have some opportunity to work on a CAES pilot project in Ontario that will use an existing cavern at a 5-10 MW scale, incorporating heat stripping and recovery to achieve elevated efficiencies. Intermediate grade geothermal energy (IGGE) is accessible at depth (kms) throughout Canada, but without C-pricing and with cheap CH4, commercialization is challenging. To help make it commercial, we need more efficient horizontal drilling and hydraulic fracturing methods for low permeability igneous rocks, use of district heating and new binary cycle cogeneration, and coupled geomechanical models that can simulate the transfer of stresses and roughly predict seismic potential so that risks can be properly managed. I am working with a broad multiple-discipline engineering team to address integrated IGGE systems, focusing on 3D stress modeling of fractured systems undergoing convective and conductive heat transfer with circulating fluids (not necessarily water!). Stresses in such a system are massively shifted as the rock cools, and the flow system is very non-linear because during cooling, the joints open and even propagate, greatly changing flow behavior. Stress transfer means regions of high stress gradients (high shear stresses) are generated, and this is what triggers seismic events. If these can be modeled, it opens the door for their management through pressure, temperature and geometry factors, an exciting area to explore in research.

加拿大未来可靠的脱碳能源需要无碳能源和电网规模的储存。两种可以纳入随机可再生能源（风能，太阳能）的电网规模存储选项是抽水蓄能和压缩空气地质存储（CAES）。我将在加拿大开发薄层盐洞CAES，使用长廊道以获得合适的体积（例如20 x30 x750 m）。巧合的是，可以从这种方法中受益的省份是那些抽水潜力很小的省份（AB，SK，ON，NB，NS）！需要新的想法来实现薄层盐廊道的一致解决（水平威尔斯、滑动套筒和端口方法），以及分析和设计方法来优化跨度选择和廊道阵列间距。顶板岩石往往是水平分层的非盐岩，当暴露于多次加压循环时，会分层和斯劳，并且必须澄清此类分析所需的材料行为规律，并将其纳入计算程序。空气进入部分分层的顶板岩层，随后在减压过程中产生压力载荷，导致顶板劣化和潜在的大规模坍塌，如果覆盖层条件不利，则可能损害洞室完整性。通过数千次压力循环将粘性盐响应与屋顶的弹塑性响应相结合是一项计算要求很高的工作。我的学生也将有机会在安大略的CAES试点项目上工作，该项目将使用现有的5-10兆瓦规模的洞穴，结合热剥离和回收，以提高效率。 中级地热能（IGGE）在整个加拿大的深度（公里）都可以获得，但没有C定价和廉价的CH 4，商业化是具有挑战性的。为了使其商业化，我们需要针对低渗透性火成岩的更有效的水平钻井和水力压裂方法，使用区域供暖和新的二元循环热电联产，以及耦合地质力学模型，可以模拟应力转移并粗略预测地震潜力，以便妥善管理风险。我正在与一个广泛的多学科工程团队合作，以解决集成IGGE系统，专注于通过循环流体（不一定是水！）进行对流和传导传热的裂缝系统的3D应力建模。当岩石冷却时，这种系统中的应力会大量转移，并且流动系统是非常非线性的，因为在冷却期间，接缝打开甚至扩展，极大地改变了流动行为。应力转移意味着产生高应力梯度（高剪切应力）区域，这就是触发地震事件的原因。如果这些可以建模，它打开了通过压力，温度和几何因素管理它们的大门，这是一个令人兴奋的研究领域。