Improving characterization and modelling of the rock-proppant interaction in hydraulic fractures for deep-earth geo-resource extraction

改进水力压裂中岩石-支撑剂相互作用的表征和建模，以进行深地地质资源开采

• 批准号: RGPIN-2021-04215
• 负责人: Zheng, Wenbo
• 金额: $ 1.89万
• 依托单位: University of Northern British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=742872
• 关键词: Improving; characterization; modelling; rock; proppant

The Canada Energy Regulator predicts Canadian natural gas production to grow to 606 million cubic metres per day over the next two decades. The production will be mainly from the natural gas reserves trapped in tight and low-permeability rock formations 2-3 km below surface. Massive amounts of proppants, mostly frac sand, are placed into fractures created by hydraulic fracturing to increase the fracture conductivity and enhance the long-term hydrocarbon recovery from tight formations. Experiences from well stimulation operations have already demonstrated that the rock-proppant mechanical interaction under high compressive stress significantly influences fracture conductivity and, thus, gas productivity. However, there is a lack of comprehensive and quantitative characterization of how fracture conductivity evolves during well production life, due to the limitations in existing laboratory tests and predictive models where complex interaction between proppants and rock is over-simplified. Many important impact factors have not yet been fully captured in the complex rock-proppant systems, such as rock fracture topography, proppant size, and proppant creep indentation into rock faces. These shortcomings have significantly impaired our ability to correctly predict proppant behaviours in rock fractures, resulting in the inappropriate selection of proppants for hydraulic fracturing. Recent progress in my research activities has identified the need to rigorously model proppant crushing between fractures for satisfactory prediction of fracture conductivity. For this, we have developed a numerical breakage model to successfully simulate grain breakage at high compressive stress. The research program proposed for this Discovery Grant will build on our existing successes and further advance the characterization and modelling of the rock-proppant interaction in fractures for resource extraction. This goal will be achieved through training HQP in interlinked research tasks with advanced laboratory geo-materials characterization, geomechanical testing, and numerical and analytical modelling. The research outcomes will deliver and promote new knowledge and tools for improving the extraction efficiency that is crucial to the sustainable development of the Canadian natural gas industry. Characterization techniques of proppants and rock and predictive models of hydraulic-mechanical behaviours will be developed to better apply proppants in hydraulic fracturing for deep earth resource recovery while minimizing environmental impacts associated with proppant mining and transportation. Close collaboration with existing industry and academic partners will ensure rapid dissemination of research outcomes and facilitate optimization opportunities in natural gas development projects. HQP will be equipped with essential skills that are highly desirable in the Canadian natural resource sector.

加拿大能源监管机构预测，未来二十年加拿大天然气产量将增至每天 6.06 亿立方米。生产将主要来自地表以下2-3公里致密低渗透岩层中的天然气储量。将大量支撑剂（主要是压裂砂）放入水力压裂形成的裂缝中，以增加裂缝导流能力并提高致密地层中油气的长期采收率。增产作业的经验已经证明，高压应力下的岩石-支撑剂机械相互作用会显着影响裂缝导流能力，从而影响天然气产能。然而，由于现有实验室测试和预测模型的局限性，支撑剂和岩石之间复杂的相互作用被过度简化，因此缺乏对井生产寿命期间裂缝导流能力如何演变的全面和定量的表征。在复杂的岩石-支撑剂系统中，许多重要的影响因素尚未被完全捕获，例如岩石裂隙地形、支撑剂尺寸和支撑剂蠕变压入岩石表面。这些缺点严重削弱了我们正确预测岩石裂缝中支撑剂行为的能力，导致水力压裂支撑剂选择不当。我的研究活动的最新进展已经确定需要严格模拟裂缝之间的支撑剂破碎，以便令人满意地预测裂缝导流能力。为此，我们开发了一个数值破碎模型，成功模拟高压应力下的晶粒破碎。为该发现拨款提出的研究计划将建立在我们现有成功的基础上，并进一步推进资源开采裂缝中岩石-支撑剂相互作用的表征和建模。这一目标将通过培训 HQP 来完成与先进的实验室地质材料表征、地质力学测试以及数值和分析建模相关的研究任务。研究成果将提供和推广新的知识和工具，以提高提取效率，这对加拿大天然气行业的可持续发展至关重要。将开发支撑剂和岩石的表征技术以及水力机械行为的预测模型，以更好地在水力压裂中应用支撑剂以进行深层地球资源回收，同时最大限度地减少与支撑剂开采和运输相关的环境影响。与现有行业和学术合作伙伴的密切合作将确保研究成果的快速传播并促进天然气开发项目的优化机会。 HQP 将配备加拿大自然资源行业非常需要的基本技能。