固井水泥浆凝固过程中地层水窜流模拟实验

Simulation experiment of formation water channeling during cementing slurry solidification

该文针对地层水窜流问题,设计了地层水窜流模拟实验。实验测量了水泥浆不同凝固状态时的窜流压力,观察分析了窜流形态,研究了窜流规律。结果表明:随着水泥浆候凝时间增长,窜流压力逐渐增大。候凝时间较短时,水泥浆内部胶凝网状结构强度较小,地层水易侵入内部形成窜流通道,但窜流通道尺寸较小;候凝时间较长时,胶凝网状结构强度增大,地层水已不能侵入内部形成窜流通道,只在侵入点附近聚集累积到一定压力后,再突破薄弱胶结界面形成窜流通道,候凝时间越长,聚集累积水量和突破压力越大。候凝时间较短时,可形成多条窜流通道,且通道宽度较大;候凝时间较长时,只能形成一条窜流通道,且随着窜流前进通道宽度逐渐变小。

Aiming at the problem of formation water channeling, the simulation experiment of formation water channeling is designed and carried out. The channeling pressure of formation water is measured when the cement slurry is in different setting states. The channeling shape is observed and analyzed, and the channeling law of formation water is studied. The results show that the channeling pressure increases gradually with the increase of cement slurry waiting time. When the waiting time is short, the cementation network structure inside the cement slurry is weak, formation water is easy to invade into the interior to form a channeling channel, and the size of the channeling channel is small. When the waiting time is long, the strength of network structure increases, formation water can’t invade the interior to form channeling channel, but first accumulates to a certain pressure near the invasion point, and then breaks through the weak cementation interface to form channeling channel. The longer the waiting time is, the greater the accumulated water and pressure are. When the waiting time is short, more than one channeling channel can be formed, and the width of the channel is large. When the waiting time is long, only one channeling channel can be formed, and the width of the channel gradually decreases with the channeling.