碱敏储层压裂损害机理与保护技术研究及应用

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

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。

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.