低温带压作业用高强度凝胶性能评价

Performance Evaluation of High Strength Gels for Low Temperature Operation with Pressure

为满足低温油井带压修井作业对凝胶高强度、成胶时间可控以及可破胶的性能要求,以多羟基聚合物P3600和自制交联剂Smel 30制得一种适用于低温环境(30~50℃)的高强度凝胶。通过SEM分析凝胶微观结构,采用万能材料机测试其抗压强度,并用黏度法研究了凝胶的成胶时间及其影响因素,考察了凝胶体系的稳定性和破胶性。结果表明,由8.75%P3600和2%Smel 30组成的凝胶体系在低温(30~50℃)、pH值为4.5数5.5的条件下稳定成胶,形成三维网状结构,本体强度可达18 N;pH值对凝胶成胶时间的影响较大,现场可通过改变pH值调节凝胶的成胶时间;金属离子可以缩短凝胶的成胶时间,可作为控制凝胶成胶时间的第二因素。该凝胶体系具有良好的抗油性和稳定性,并且在带压作业结束后可迅速破胶为流体,满足带压作业要求。

In order to meet the requirements of high gel strength,controllable gelation time and broken gelation in low-temperature oil well with pressure workover,a tough gel which was suitable for low temperature environment with 30-50℃,was made of polymer P3600 and self-made crosslinking agent Smel 30.The bonding mechanism could be studied by the analysis of its microstructure through SEM.Through the strength of the gel tested by universal material machine and the gelation time and relevant contributing factors studied by viscosity method,the stability and breaking properties of gel were investigated.The results showed that the gel composed of 8.75%P3600 and 2%Smel 30 could stabilize into gel when the temperature was 30-50℃and pH value was 4.5-5.5,and form a three-dimensional network structure,whose strength reached 18 N.The gelation time of gel was influenced by pH value,which could be adjusted by the control of pH value on site.Metal ions could shorten the gelation time,which could be used as another factor to control the gelation time.The gel system had good oil resistance and stability,and could break quickly into fluids after pressure operation,which met the requirements of pressure operation.