Hydraulic fracturing is recognized as the primary technique to achieve economic oil and gas production from low permeability reservoirs like shale and tight-sand formations. One of the main challenges facing the oil and gas industry is maintaining the proppant functionality in the subsurface to guarantee a sustainable production rate and higher ultimate recovery. Proppant crushing and proppant embedment may diminish production from stimulated wells especially when bottomhole pressure is reaching low flowing pressures in soft and deep formations like Haynesville or Tuscaloosa Marine Shales. Experimental measurements and field observations have shown the strong impact of proppant stress and proppant embedment on reducing fracture conductivity. In this work, we introduce a novel material developed in order to achieve higher fracture conductivities at a minimum cost. The new type of proppants, so called "Expandable Proppants" (EP), is able to remotely control the expanding force and maintain the functionality of placed proppants. The presented proppants are made out of thermoset shape memory polymers which are activated by formation’s in situ temperature to effectively maintain or even increase fracture’s width. A fully coupled numerical model is developed to study the effectiveness of expandable proppants and evaluate fracture conductivity enhancement for different combinations and distributions of EP. In addition, a series of experiments were conducted in a modified API conductivity cell to verify the increase in fracture conductivity. Numerical and experimental results demonstrate that proppant expansion can increase the permeability up to 100%. Different conditions of confining stress and proppant sizes are studied to verify the optimum proppant design. This product can extend the lifetime of the fracture and ensure lasting production.

水力压裂被认为是从低渗透性油藏（例如页岩和致密砂岩地层）实现经济油气生产的主要技术。石油和天然气工业面临的主要挑战之一是保持地下支撑剂的功能性，以确保可持续的生产率和更高的最终采收率。支撑剂压碎和支撑剂包埋可能会降低增产油井的产量，尤其是当海恩斯维尔或塔斯卡卢萨海洋页岩等软深层地层的井底压力达到较低的流动压力时。实验测量和现场观察表明，支撑剂应力和支撑剂包埋对降低裂缝导流能力有很大影响。在这项工作中，我们介绍了一种新颖的材料，旨在以最低的成本获得更高的断裂电导率。新型支撑剂，称为“可膨胀支撑剂”（EP），能够远程控制膨胀力并保持所支撑支撑剂的功能。提出的支撑剂由热固性形状记忆聚合物制成，该聚合物由地层的原位温度活化，以有效地维持甚至增加裂缝的宽度。建立了一个完全耦合的数值模型，研究了可膨胀支撑剂的有效性，并评价了EP的不同组合和分布下的裂缝电导率的提高。此外，在修改后的API中进行了一系列实验电导率电池，以验证断裂电导率的增加。数值和实验结果表明，支撑剂膨胀可以将渗透率提高到100％。研究了限制应力和支撑剂尺寸的不同条件，以验证最佳支撑剂设计。该产品可以延长裂缝的寿命并确保持久的生产。