Oil well casing refers to the pipe that enters the well after drilling. The casing and the well wall are sealed with cement, and then a perforating gun is used to perforate the target layer to allow the oil to flow through the rock layer and cement sheath. and capitalization. At the bottom of the well, pipe into the ground.
Oil well casing can be divided into conduit, surface casing, technical casing and oil layer casing according to its usage. Each well uses several layers of casing based on different drilling depths and geological conditions. Cement must be used to cement the casing after it is lowered into the well. Unlike oil pipes and drill pipes, it cannot be reused and is a one-time consumable material. Therefore, the consumption of casing accounts for more than 70% of all oil well pipes.
The main functions of oil well casing are:
1. Reinforce the well wall to prevent formation collapse;
2. Seal different oil layers and water layers to achieve layered production;
3. Promote the implementation and maintenance of fracturing, acidification and other measures;
4. Form an oil flow channel and cooperate with the oil pipe to achieve the purpose of oil return;
The sequence is as follows: after laying the oil well, drive the casing, seal the casing and well wall with cement, and then lay the oil pipe in the casing. On the pipeline are downhole tools such as oil packers and pumps. The sucker rod is inserted into the pipe. The sucker rod pulls the piston of the pump to reciprocate up and down. In this way, the oil is pumped to the surface.
