What are the reasons for oil casing jam?

Oil casing is a pipe used to support the wall of oil and gas wells to ensure the normal operation of all oil wells during the drilling process and after completion. Each well can choose a certain amount of oil casing according to the different drilling depths and geographical conditions. After the casing is placed in the well, concrete cementing is used. It is different from oil pipes and drill pipes and cannot be used multiple times. It is a single-consumable material.

There are two reasons why oil casing is stuck: sticking and suction; well wall collapse or sand bridge. When oil casing is stuck, it can be fully pressed, but it cannot be lifted more. The annular gap between the casing and the well wall is small, and it cannot be milled and undercut.

In case of sticking, add a de-stuck fluid to remove the stuck drilling fluid under the condition that the drilling fluid can be repeatedly drained, which is the same as the method for dealing with sticky and suction drilling fluid. In case of collapse or sand jam, a sand bridge has been formed in the well, but some drilling fluid has returned. The drilling fluid viscosity and shear force should be increased by low displacement and low pump pressure repeatedly to restore the drilling fluid and then cement the well after repeated drilling. The oil casing has been put into the well, and leakage occurs when collapse or sand jam occurs. Analyze the leakage layer, and quickly cement the well to squeeze the cement slurry into the leakage layer. If the oil casing has not been put into the well, but is very close to the target formation, you can first cement the well, then drill through the concrete plug and casing shoe, and repeatedly pass the well to the bottom, and then use the tail pipe hanging method to seal the oil and gas layer.