The tubing is a tube that is lowered into the casing pipe of the well, when the well is being produced normally. From the well, the oil flows through the
casing pipe into the ground and enters the gathering process. In the coal mining well, the combination of oil pipe, sucker rod and deep well pump (ie “three pumping” equipment) draws oil to the ground and enters the gathering process. The casing is a pipe that is lowered into the well after the drilling is completed. The casing and the well wall are cement-sealed, and then the perforating gun is used to align the perforation of the target layer, so that the oil flows through the rock layer, the cement ring, and the casing into the well. At the bottom, enter the tubing and come to the ground.
The main functions are: 1. Reinforce the well wall to prevent the formation from collapsing; 2. Separate different oil layers and water layers to achieve layered mining; 3. Facilitate the implementation of fracturing and acidification operations and maintenance operations. 4. The formation of oil flow channels, with the oil pipe to achieve the purpose of oil recovery.
Seamless oil casing failure is one of the major problems encountered in each field, especially the most severe failure of threaded joints. According to statistics, the oil casing failure occurred in about 64% of the screw connection accidents. The domestic figure is as high as 86%. The fixed oil casing threaded joint is the weak link of the oil casing string. Therefore, increasing the quality of the threaded connection is to ensure the column. The key factor of quality. The oil casing threading used in the stress distribution directly determines the strength of the connecting string.
The stress distribution in the research section not only provides the manufacturer with a basis for optimizing the oil casing thread design, the casing and the tubing used to predict performance. The order is: after the oil well is laid, the casing is placed, the casing and the well wall are sealed with cement, and the oil pipe is placed in the casing. The oil pipe is equipped with a downhole tool such as an oil packer and a pump. The sucker rod is inserted into the oil pipe, and the sucker rod pulls the piston of the pump to reciprocate up and down. In this way, the oil is pumped to the ground.
Seamless steel tubing is the largest number of pipelines used in oil and gas exploration, it relies on internal and external threaded male buckles to work a series of deep buried underground steel pipes. Oil well casing is the lifeline of its quality, directly affecting the success of drilling operations and the service life of oil and gas wells, involving the economic benefits of oil fields and manufacturers.
The seamless oil casing joint is a male and female snap contact surface composed of an external thread male buckle and a belt buckle inner thread nut. This is a spiral surface, and the cooperation force with the oil pipe is more complicated. In addition to tightening the torque generated by the contact pressure, it is also subjected to loads such as tension and pressure (caused by oil, gas or other medium). The joint force analysis of the oil casing involves the nonlinearity of the material, the geometric nonlinearity and the complexity of the contact friction conditions to establish a complete and accurate mathematical model, and the analytical solution is difficult.
