低温环境下泵送桥塞作业井口密封脂的选择

Selection of Sealing Grease for Wellhead of Pumping Bridge Plug Operation at Low Temperature

水平井泵送桥塞分段压裂作业已成为低渗透油气藏的主要改造方式,电缆输送联作管串过程中,为保证井口油气不泄漏,采用注脂方式进行密封.在东北低温环境条件下,密封脂流动性变差,泵送作业难度大,为保证冬季泵送作业顺利进行,针对密封脂黏温性能进行了室内实验,获得不同型号密封脂的黏温特征曲线,结合电缆密封控制系统数学模型及施工经验,在不同泵送压力情况下计算了密封脂黏度的选择区间,结合实际施工情况,推荐了适用于不同压力级别的密封脂型号.

Pumping bridge plug fracturing operation in horizontal wells has become one major method of reconstructing low permeability reservoirs. Sealing is conducted by injecting grease in the process of cable transmission joint pipe string to ensure that oil and gases do not leak at wellheads. In the typical low temperature condition of Northeast China, the fluidity of sealing grease deteriorates, and pumping operation becomes more difficult. To ensure the pumping operation in winter, a laboratory experiment was carried out to study the viscosity-temperature performance of sealing greases during which the viscosity-temperature characteristic curves of different types of sealing greases were obtained and used for calculating the selection interval of sealing grease viscosity at different pumping pressures using cable sealing control system mathematical model while taking construction experiences into consideration, and relevant types of sealing greases suitable for use at relevant pressure levels were recommended while considering the actual construction conditions.