暂堵技术在致密砂岩气藏压裂中的应用

Application of temporary plugging technology in fracturing of tight sandstone gas reservoir

鄂尔多斯地区蕴藏着大量的天然气,拥有典型的低渗透、低压、低产、多层系、非均质性较高的致密气资源。常规压裂法开采工艺不佳,无法实现预期的开采效益,为此,提出暂堵技术在致密砂岩气藏压裂中的应用。针对储层地质特征的特点,采用高强度、高封堵性能、易降解的暂堵剂,在纵向上完成多层系统的临时封堵和分层迁移,达到缝内转向的目的,形成新的分支裂缝,使气藏的改型容积和气密性得到明显的改善。该工艺应用后,暂堵区的压力平均提高了3 MPa。断裂的平均长度比普通压裂段增加5.8%,断裂长度增加12.5%,保证复杂缝网的生成结果,可广泛地进行实际应用。

Ordos area contains a large amount of natural gas, with typical tight gas resources of low permeability, low pressure, low production, multi-layer system and high heterogeneity.The conventional fracturing technology is not good enough to achieve the expected production benefits.Therefore, the application of temporary plugging technology in the fracturing of tight sandstone gas reservoirs is proposed.According to the geological characteristics of the reservoir, the temporary plugging agent with high strength, high plugging performance and easy degradation is used to complete the temporary plugging and layered migration of the multi-layer system in the vertical direction, so as to achieve the purpose of turning in the fracture, form new branch fractures, and significantly improve the modified volume and gas tightness of the gas reservoir.After the application of this process, the pressure in the temporary plugging area has increased by 3 MPa on average.The average length of fracture is 5.8% longer than that of ordinary fracture section, and the fracture length is 12.5% longer, which can ensure the generation of complex fracture pattern and can be widely used in practical applications.