Nanoparticle-assisted enhanced oil recovery (Nano-EOR) in unconventional oil reservoirs

加拿大拥有巨大的非常规石油资源，而常规石油储量在全球范围内正在枯竭。例如，加拿大西部和美国邻近各州的巴肯地层约有2710-5030亿桶轻质石油储量。在这种致密的地层中，一次采油的采收率低至1-3%。另一方面，加拿大的重油储量估计为550亿桶。典型的带砂冷稠油开采(CHOP)可以回收5-15%的稠油，因此85-95%的稠油留在加拿大CHOP后的储集层中进行开采。在许多情况下，传统的提高采收率(EOR)工艺不能有效、经济地开发这些非常规油藏。在过去的十年里，一些有限的跨学科研究表明，纳米技术在提高采收率方面可能有很大的前景。特别是，与传统三次采油过程中常用的水、溶剂、化学品和水蒸气相比，尺寸为1-100 nm的纳米颗粒作为三次采油剂表现出了一些显著的特点。因此，NP辅助提高采收率(简称Nano-EOR)可能为非常规油藏的开发提供一种有效的、新颖的提高采收率技术。目前，Nano-Eor还处于初级阶段。纳米三次采油技术能否在油田成功应用仍是个未知数。拟议的NSERC DG研究计划的主要目标是为非常规油藏提供急需的新型纳米提高采收率技术的创新和基础研究。一些现有的或新的实验方法、分析技术、数学模型和数值模拟将被应用于以下三个主要研究目标。首先，我们将研究和开发一些稳定的、适用于纳米三次采油的纳米流体。其次，将测量和模拟NP在多孔介质中的滞留。第三，将对几种有前景的基于水和/或二氧化碳的纳米提高采收率工艺进行实验测试和数值模拟，以确定巴肯地层和加拿大印章后储层中各自最好的纳米提高采油工艺。这一新的DG研究计划将通过研究纳米提高采收率的新工艺中NPs、油藏流体和地层之间的提高采收率机制和复杂相互作用来产生新的知识。它将为未来的纳米三次采油项目提供及时、直接和强有力的技术支持。加拿大石油业将通过实施一些有效的纳米提高采收率项目并从几个巨大的富油地层中回收剩余的轻质和重质石油，将大大受益。此外，纳米三次采油还将有助于减少轻油生产中的水和溶剂使用量以及重油生产中的温室气体排放。从长远来看，加拿大将继续开发新颖和先进的提高采收率技术，加拿大人也将继续节约充足的淡水和清洁的空气。

Canada has tremendous unconventional oil resources, while the conventional oil reserves are being depleted worldwide. For example, the Bakken formation in Western Canada and the adjacent US states has approximately 271-503 billion barrels of light oil-in-place. The oil recovery factors of the primary production in such a tight formation are as low as 1-3%. On the other hand, the Canadian heavy oil reserves are estimated to be 55 billion barrels. A typical cold heavy oil production with sand (CHOPS) can recover 5-15% and thus 85-95% heavy oil is left in the Canadian post-CHOPS reservoirs to be recovered. In many cases, the traditional enhanced oil recovery (EOR) processes cannot effectively and economically exploit these unconventional oil reservoirs. In the past decade, some limited cross-disciplinary studies have indicated that nanotechnology may hold great promise for EOR purposes. In particular, nanoparticles (NPs) with sizes of 1-100 nm show some remarkable characteristics as new EOR agents, in comparison with water, solvents, chemicals and steam that are commonly used in the traditional EOR processes. Thus NP-assisted EOR, which is abbreviated as Nano-EOR, may offer an effective and novel EOR technology to exploit the unconventional oil reservoirs. At present, Nano-EOR is in its infancy. It is still unknown whether Nano-EOR technology can be successfully applied in the oilfields. The primary objective of the proposed NSERC DG research program is to deliver much-needed innovative and fundamental studies of novel Nano-EOR technology for the unconventional oil reservoirs. Some existing or new experimental methods, analytical techniques, mathematical models and numerical simulations will be applied to pursue the following three major research objectives. First, some stable and suitable nanofluids (NFs) will be studied and developed for Nano-EOR. Second, NP retention in a porous medium will be measured and modeled. Third, several promising water- and/or CO2-based Nano-EOR processes will be experimentally tested and numerically simulated to identify the best respective Nano-EOR processes in the Bakken formation and Canadian post-CHOPS reservoirs. This new DG research program will generate new knowledge by studying the EOR mechanisms and complex interactions among NPs, reservoir fluids and formations in the novel Nano-EOR processes. It will provide timely, direct and strong technical support for future Nano-EOR projects. The Canadian petroleum industry will benefit considerably by conducting some efficient Nano-EOR projects and recovering the remaining light and heavy oils from several vast oil-rich formations. Furthermore, Nano-EOR will also help to reduce water and solvent usages in the light oil production and greenhouse gas emissions in the heavy oil production. In the long run, Canada will continue to develop novel and advanced EOR technologies and Canadians will also continue to conserve abundant fresh water and clean air.