Research on damage mechanism of casing based on fluid-structure coupling and perforation performance of new perforation device

Jet perforating is an important way to improve oil and gas recovery. The metal jet formed by the traditional perforating method will cause serious damage to the casing, reduce the life of casing and oil and gas well, and affect the later oil and gas exploitation. In order to solve the problems existing in the current perforating method, a combination of mechanical and shaped charge perforating method is proposed. The method firstly drilled the casing surface by mechanical means, and finally penetrated the formation through the perforating charge to form oil and gas channel. According to the traditional perforating technology, the casing damage mechanism is analyzed by finite element method, and the conventional perforating method is compared with the new perforating method. The results show that the traditional perforating method will cause casing damage. The hole diameter of the outer wall of the casing is 12.20 mm, and the damage range of the outer wall of the casing is 32.10 mm. The stress, strain and damage range of the inner wall of the casing are smaller than that of the outer wall during the perforating process, and the radial damage of the casing changes up and down, and the shape is like "sawtooth". According to the new perforating method, the combined perforating method of mechanical and shaped charge causes less damage to the casing, and the perforating depth is increased by 11.37%. When the drill diameter on the new device is 20 mm, the damage caused by the perforating charge to the casing is 0. Therefore, the new perforating method can not only reduce casing damage but also increase the perforating depth, which is of great significance for improving the life of oil and gas Wells and oil and gas recovery.