Z35 区块调整井可固化隔离液技术研究与应用

江苏油田Z35 区块存在调整井固井质量差、环空油气水窜现象，分析其原因是由于井壁虚泥饼及窝存的死泥浆造成了界面胶结质量较差。针对这一问题，室内研发了一种新型可固化隔离液体系，该体系主要由悬浮剂、固化剂、激活剂组成。实验结果表明:该体系90 ℃下沉降稳定性不大于0.01 g/cm3，根据现场情况配制了密度范围在1.40~1.80 g/cm3 的可固化隔离液体系，在50~90 ℃条件下具有稳定的流变性能；可固化隔离液中聚磺钻井液加量在0~75% 范围内均能实现固化，江南G 级水泥浆中掺入25% 的可固化隔离液在90 ℃条件下养护48 h，抗压强度高达16.69 MPa；与钻井液、水泥浆具有良好的相容性，与水泥浆不同比例混合后均能延长稠化时间，降低水泥浆的滤失量，对水泥浆初始稠度影响甚微；通过合理调整密度剂的加量， 可以配置密度范围在1.4~1.8 g/cm3 的可固化隔离液。江苏油田Z35-28 井?139.7 mm 油套固井的成功应用表明，该体系可以达到高效顶替、有效隔离、平衡固井的目的。

Development and application of curable spacer fluids for adjusting wells in Block Z35

Adjusting wells in Block Z35 of Jiangsu Oilfield are characterized by poor cementation quality and severe oil/gas/water channeling in annular space. These problems were caused predominantly by poor cementation quality on interfaces due to existence of mud cake on sidewall and died mud in borehole. To eliminate them, an innovative curable spacer fluid system was developed, which is mainly composed of suspending agents, curing agents and activator. Test results show that setting stability of the system at 90 ℃ is not higher than 0.01 g/cm3. In accordance with field conditions, 1.40-1.80 g/cm3 curable spacer fluid system with a density of 1.40-1.80 g/ cm3 was prepared. The system has reliable rheological characteristics at 50-90 ℃. Curable spacer fluids with polysulfonate drilling fluid of 0-75% may achieve desirable performances. Cement slurry of Jiangnan Grade G with mixing of 25% curable spacer fluids cured for 48 h at 90 ℃ may have compressive strength up to 16.69 MPa. The newly-developed system has desirable compatibility with drilling fluid and cement slurry. Mixed with cement slurry at different proportions, the system may effective prolong thickening time and reduce filtration loss of cement slurry with minor impacts on initial viscosity of the cement slurry. Through proper adjusting of volumes of weighting materials deployed, curable spacer fluids with densities of 1.4-1.8 g/cm3 can be prepared effectively. Successful application of the system in Well Z35-28 completed with ?139.7 mm tubing casing in Jiangsu Oilfield show the system can enhance displacement efficiency to achieve balanced cementation with effective separation.