When cold fluid is injected into low-temperature, low-pressure, low-permeability reservoirs containing wax-bearing heavy oil, cryogenic paraffin deposition and heavy oil condensation will occur, thus damaging the formation. Moreover, the formation pressure coefficient is low and the working fluid flowback efficiency is low, which affects the fracturing stimulation effect. Therefore, an in situ heat/gas clean foam fracturing fluid system is proposed. This system can ensure that conventional fracturing fluid can create fractures and carry proppant in the reservoir, generate heat in situ to avoid cold damage, reduce the viscosity, and improve the fluidity of crude oil. The in situ heat fracturing fluid generates a large amount of inert gas while generating heat, thus forming foam-like fracturing fluid, reducing fluid loss, improving proppant-carrying performance, improving gel-breaking performance, effectively improving crack conductivity, and is clean and environmentally friendly. Based on the improved existing fracturing fluid system, in this paper, a new type of in situ heat fracturing fluid system is proposed, and a system optimization evaluation is conducted through laboratory experiments according to the performance evaluation standard of water-based fracturing fluid. Compared with the traditional in situ heat fracturing fluid system, the fracturing fluid system proposed in this study generates a large amount of inert gas and form foam-like fracturing fluid, reduces fluid loss, enhances the proppant-carrying capacity and gel-breaking performance, improves crack conductivity, the gel without residue and that the gel-breaking liquid is clean and harmless.

当将冷流体注入到包含蜡质稠油的低温，低压，低渗透油藏中时，就会发生低温石蜡沉积和重油凝结，从而损害地层。而且，地层压力系数低，工作流体回流效率低，影响了压裂增产效果。因此，提出了一种原位热/气清洁泡沫压裂液系统。该系统可以确保常规压裂液会产生裂缝并在储层中携带支撑剂，就地产生热量，避免冷害，降低粘度，并提高原油的流动性。原位热压裂液在产生热量的同时会产生大量的惰性气体，从而形成泡沫状的压裂液，减少了流体的损失，改善了支撑剂的承载性能，破胶性能，有效地提高了裂缝传导性，并且清洁，环保。在改进现有压裂液体系的基础上，提出了一种新型的原位热压裂液体系，并根据水基压裂液的性能评价标准，通过实验室实验对体系进行了优化评价。与传统的现场热压裂液系统相比，本研究提出的压裂液系统产生大量的惰性气体，形成泡沫状的压裂液，减少了流体损失，提高了支撑剂的承载能力和破胶性能，改善裂纹传导性，凝胶无残留，破胶液干净无害。