碱敏储层压裂损害机理与保护技术研究及应用

在压裂施工过程中,碱敏储层受高pH值流体的影响,可产生矿物组份二次沉淀、转移以及粘土膨胀率增加、二价金属离子化合物沉淀等反应而对储层造成严重损害.针对中原油田桥口、白庙与户部寨地区储层特点,分析了强碱性压裂液对碱敏储层的损害机理,研究了液体pH值、储层温度、滞留时间等因素与碱敏储层损害的关系,提出了防止碱敏损害的预前置液、缓冲剂等技术,并在现场进行了7井次压裂施工应用.通过选择合适的液体组成体系,可以有效地抑制储层碱敏损害,达到保护地层、提高压裂效果的目的.

Study and Application of Fracturing Damage Mechanism and Protection Technology to Alkali-sensitive Reservoir

In the process of fracturing,the secondary mineral components precipitation,migration,clay swelling rate increasing and bivalent metallic ion compounds deposition could been occurred in alkali-sensitive reservoirs because of the influence of high-pH fluids.According to the characteristics of Qiaokou,Baimiao,Hubuzai reservoirs in zhongyuan oilfield,we analyzed the damage mechanism of the strong alkalinity fracturing fluids to alkali-sensitive reservoirs,studied the relationship between the fluid pH value,formation temperature and detention time factors and alkali-sensitive reservoirs,finally got the technology of ahead prepad fluid and buffering agents which is used to prevent the alkali-sensitive damage,and conducted 7 wells field applications.Selected the proper fluid system,alkali-sensitive damage could be inhibited,and the formation prevention and fracture effect enhanced.