During cementing operation, pumping cement and displacement fluid can lift the casing. Some people call “pump out of the well”. This situation can be occurred and there are some reasons as follows:
• Lightweight casing string
• Large casing diameter
• High density of cement
• Low density of displacement fluid
• High annular pressure loss
• High pressure trapped in the annulus due to bridging
How is the casing lifted during cementing?
Under A Static Condition
The casing can be hydraulic out of hole due to unbalance of hydrostatic pressure. See the figure below for more understanding.