川西低固相钻井完井液泥饼清除技术初探

Study on Filter Cake Removal Technology of Low Solid Drilling and Completion Fluids in Chuan Xi

针对川西地区钻井完井液在井壁上形成的泥饼完井后影响固井质量和造成油气通道堵塞的问题,进行了室内泥饼清除实验。通过实验得知,生物酶破胶剂和氧化破胶剂NaClO无法降解目前配方中的聚合物,但是能降解纤维素类钻井液,因此选用增黏剂HV-CMC和降滤失剂LV-PAC、SL-PAC来提高生物酶和氧化破胶剂NaClO对泥饼的清除作用。根据黏度降低率和渗透率恢复率结果,可推荐固井冲洗液中加入氧化破胶剂NaClO或生物酶来提高冲洗液的清洗效果,而对川西地区致密性砂岩储层的泥饼推荐复配使用氧化破胶剂和酸液进行清除。

The filter cake must be removed for its bad effect on cementing quality and oil and gas channels.Laboratory study shows that specific enzyme and oxidizer NaClO can not degrade the polymer effectively in the present formula,but it can degrade the cellulose drilling fluids,so natural high polymer HV-CMC and fluid loss additive LV-PAC and SL-PAC are chose to improve the cleaning efficiency.Based on the analysis of viscosity reduction and permeability recovery experiment,enzyme and oxidizer NaClO can be added into cementing flushing fluid,and oxidizer mixed acid can be used to remove the filter cake of tight sandstone reservoir in Chuanxi.