长裸眼恶性漏失井双重防漏固井技术

Dual Prevention of Severe Losses of Cement Slurries in Cementing Long Open Holes

针对长裸眼恶性漏失固井难题,研制了温敏形状记忆防漏隔离液和泡沫防漏水泥浆,两者协同增效降低长裸眼恶性漏失井固井漏失风险。研发的温敏形状记忆材料耐温150℃,形变记忆温度80~110℃,制备的温敏形状记忆变形网颗粒形变后长度为常温状态的10倍,制备的温敏形状记忆膨胀球膨胀后粒径为常温状态的3倍,研制的温敏防漏隔离液综合性能良好,3 mm裂缝承压堵漏达8.5 MPa。研选了高性能发泡剂和稳泡剂,研制的泡沫水泥浆密度1.12~1.31 g/cm^(3)可调,上下密度差小于0.01 g/cm^(3),1.12 g/cm^(3)泡沫水泥石30℃下养护72 h后抗压强度可达6.4 MPa,水泥石中气泡均匀分散。形成了考虑等效堵漏时间和冲洗效率的堵漏隔离液段长的设计方法,制定了泡沫水泥浆分段恒气量注气方式。基于温敏防漏隔离液和泡沫水泥浆双重防漏的固井技术现场应用2井次,一次性封固段长超4000 m,隔离液和水泥浆均成功返到地面,固井质量良好。

Aiming at the cementing problem of long open hole malignant leakage wells,the thermo-sensitive shape memory loss prevention spacer and foam leakage prevention cement slurry were developed,which synergistically reduce the cementing loss risk of long open hole malignant leakage loss wells.The thermo-sensitive shape memory material was developed,which resistance temperature is 150℃and deformation memory temperature is 80~110℃,the length of thermo-sensitive shape memory mesh particles after deformation is 10 times that of normal temperature,and the diameter of shape memory expansion ball after expansion is 3 times that of normal temperature.The thermo-sensitive leak-proof spacer was developed,and the bearing-capacity of 3mm crack can reach 8.5MPa.Foaming agent and foam stabilizer were selected,and foam cement slurry were developed,and the density can be adjusted from 1.12 to 1.31 g/cm^(3),the difference between the upper and lower parts was less than 0.01 g/cm^(3),and the compressive strength of 1.12 g/cm^(3)foamed cement stone can reach 6.6 MPa at 30℃/72 h,and bubbles in set cement are uniformly dispersed.The spacer duration design method that considering the equivalent plugging time and washing efficiency was established,and the foamed cement slurry section constant gas injection method was formed.Based on thermo-sensitive anti-leakage spacer and foam cement slurry,The leak-proof cementing technology has been applied for 2 Wells,and the one-time sealing section length exceeds 4000 m,and the spacer and cement slurry returned to the surface successfully and got good results.