Theperforating gun is usually a completely closed cavity formed by the gun head, gun body and gun tail. Its function is to protect the innerperforatingbullets, bullet racks, detonating cords, detonators and other components from the high temperature and high pressure acid and alkali in the mine. And the influence of complex environment such as vibration and impact during construction, to ensure the reliable detonation of blasting equipment such asperforating bullets. The processing of the gun body is mainly the processing of the sealing surface and thread, and some manufacturers have serious defects in the processing materials of the gun body in order to save costs. The degree of fit is not enough, and there are differences in the tightness of the thread fit and the length of the thread fit during processing. It often causes the well fluid to seep into the gun body under high pressure, causing theperforating bullet and the detonating cord to be damp and affect the energy gathering effect, resulting in the occurrence of gun jamming accidents. The processing of the blind holes on the gun body is also very important. The arrangement of the blind holes on the gun body is right-handed, with a diameter of ¢32mm and a wall thickness of not less than 4mm. The processing of the bullet holder is mainly hole processing, and the positioning in the processing of the bullet holder is very important. The first hole must correspond to the blind hole of the gun body. However, there are many types ofperforating guns, and the manufacturers of the bullet holder are different, which will inevitably cause serious damage to the perforation operation. A certain degree of difficulty, such as unqualified material of the bullet frame, causing serious deformation and bending of the bullet frame, unreasonable assembly of the bullet frame and perforating charges, and inaccurate positioning of the bullet frame and the gun body. The unreasonable design of the bias weight and bearing of the bomb rack of the horizontal well, the large deviation of the hole distance and the phase angle and other factors. During the perforation operation, the perforation will deviate from the blind hole to form irregular holes, which will easily cause the gun to get stuck.
The ideal state of theperforating operation is: the perforating bullets explode at the same height in the gun, the detonation time is the same, the drug-shaped cover is crushed at the same time, and the layer opening time for the jet to reach the target layer is the same. Only by increasing the internal explosion height of the perforating gun can the formation penetration ability be effectively improved. In oil development,perforating bullets with large aperture, deep penetration, and high hole density are often used to reduce the thickness of the gun body and increase the blast height. When the blasting height increases to a certain level, it will affect the penetration ability of perforation, resulting in a decrease in oil recovery development capability. What gun type should be selected and what type of bullet should be selected, and the hole pattern, hole density, aperture, phase angle and temperature resistance should be reasonably selected. Theperforatingbullet type with high pressure can ensure the smooth progress of the perforating operation.
Accessories such as sealing rings, top wires, explosion-proof bodies and centralizers cannot be ignored inperforating operations. Sealing rings with different temperature resistance indicators should be selected according to well conditions. Polyfluororubber materials should be used in perforating construction with high well temperature. For seals, high-temperature sealing grease and high-temperature thread oil are used at the same time, and some manufacturers reduce processing procedures, and the quality of materials is poor. The temperature resistance index of the sealing ring cannot meet the construction requirements, and air bubbles are easy to form at high temperatures, which affects the sealing effect of the gun body. The opening and closing of the explosion-proof body box is not easy, the diameter of the centralizing body is not uniform, and the jacking wire processing is not strict, etc., all of which will affect the perforation.
The industry has caused accidents such as exploding guns, jamming guns, not passing explosions, and gun bodies falling into wells.
Errors in the temperature resistance and pressure resistance indicators of the initiator, detonating cord, and booster tube also have a certain impact on theperforating operation. High temperature and high pressure resistant detonating cord 170℃, 80MP. Detonator 170℃, 70MP, pressure initiator 160℃/48h, pressure 60MP or 220℃/36h, pressure 100MP, the detonator is the key component to ensure the success rate of perforation and normal detonation. The original high-temperature pressure detonator device used single-shear pins, and the pin material was copper H62. Since the temperature and pressure resistance indicators of the pin design did not take into account the downhole temperature and pressure, various indicators were based on ground experiments. The influence of downhole conditions makes the error of shear value larger. The detonation pressure ratio is accurate during pressurized detonation, which often exceeds the designed detonation pressure, causing the gun body to fail to detonate, and the effect is difficult to estimate, often resulting in rework, burying various hidden dangers for the operation team, and also adversely affecting theperforating operation.
Post time: Sep-01-2023
