The oil casing is a pipe that is put into the well after drilling. The oil casing and the well wall are sealed with concrete, and then the target layer is perforated with a perforating gun, so that the oil flows through the rock layer, concrete ring and oil casing into the bottom of the well, and then into the tubing to the ground. The specific functions are: 1, fixed shaft wall, avoid stratum collapse; 2. Seal different oil and water layers to realize layer-by-layer mining; 3. It is conducive to complete fracturing, acidification and other measures and maintainable operations. 5, the establishment of oil flow channel, with tubing to achieve the goal of oil production.
The sequence is: after the oil well is finished, the oil casing is put into the oil casing, the concrete between the oil casing and the well wall is sealed, and the oil pipe is put into the oil casing. There are oil packers, pumps and other downhole tools on the oil pipe. The sucker rod is put into the oil pipe, and the sucker rod pulls the piston rod of the pump to move up and down repeatedly. In that case, the oil is pumped out of the ground.