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

点击翻译按钮获取中文摘要

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.