In oil drilling operations, the perforating gun, as a key piece of equipment connecting the wellbore and the oil and gas reservoir, directly determines the efficiency and safety of oil and gas extraction. This precision tool, through high-pressure shaped charge jet technology, constructs efficient channels in casing, cement sheaths, and formations. Its technological evolution and performance breakthroughs are driving oil and gas development towards deeper and more complex formations.
The core principle of the perforating gun is based on the shaped charge effect, utilizing the concentrated energy release characteristics of explosive detonation. When the perforating charge is detonated, the conical shaped charge liner melts instantly under high temperature and pressure, forming a metal jet with a velocity of up to 8000 meters per second. This process is like “focusing” the energy of the explosive into a thin energy beam, continuously penetrating 15-25 mm thick casing, 50-100 mm thick cement sheaths within 30 microseconds, and ultimately penetrating more than 2000 mm into the formation. Taking the “Qingmao” brand Type 127 ultra-deep perforator from Daqing Oilfield as an example, its kinetic energy ultra-deep penetration technology improves jet stability by 40%, setting a world record of 2895.6 mm penetration depth in 2024, representing a 38% increase in penetration power compared to traditional equipment.
Structural innovation is key to the leap in perforation gun performance. Modern perforating guns generally adopt an internal blind hole design, machining precise blind holes on the inner wall of the gun corresponding to the perforation projectile position, increasing the blast height (distance between the perforation projectile and the target) by 2-3 times. This design not only reduces jet energy loss but also reduces void interference by shortening the energy transfer path. The “Pioneer” series perforators developed by CNPC Logging, through a “double-cone, double-arc, four-combination” shaped charge liner structure, improves jet conversion efficiency by 23%, and combined with nano-metal powder materials, achieves a penetration depth of 2662 mm in a 2000-meter span perforation section. The large-aperture deep-penetrating perforating gun innovatively combines large-aperture and deep-penetrating projectiles, creating channels with a diameter of over 15 mm while maintaining penetration depth, effectively reducing oil production pressure, and is particularly suitable for heavy oil reservoir development.
A positioning accuracy control system ensures millimeter-level errors in perforation operations. The magnetic locator, acting as an “underground navigator,” controls positioning errors to within 0.1 meters by detecting changes in the magnetic field generated by the casing coupling. In horizontal well operations, pump-driven segmented perforation technology, combined with drillable bridge plugs, can achieve high-precision perforation of 30-40 segments per well, with 8-10 clusters per segment. The 8880-meter Asian vertical depth record set by CNPC logging in the Southwest Oil and Gas Field was achieved through the coordinated operation of this positioning system and a special perforating gun with a temperature resistance of 200℃ and a pressure resistance of 210 MPa.
Breakthroughs in materials science and pyrotechnics technology provide assurance for operations in extreme environments. To address the high-pressure environment of the deep sea, the R&D team used rare earth elements to reinforce the pipes, combined with a composite sealing structure of “O-ring perfluororubber seals + polymer plastic retaining rings,” maintaining zero leakage at 1500 atmospheres. Regarding pyrotechnics, by optimizing detonation parameters, the delay error was controlled to within 0.1 milliseconds, ensuring the safety of simultaneous detonation of tens of thousands of tons of explosives. The new composite material perforating projectile developed by Daqing Oilfield maintains structural stability even at 200℃, successfully solving a technical challenge in the development of the Gulong shale oilfield.
From the hand-developed Qing 66-1 perforating projectile in 1965 to the complete technical system of over 130 products across 8 series today, China’s perforation technology has leaped from follower to leader. When the “Qingmao” perforator etched its mark at a depth of 2895.6 mm, and when the “Xianfeng” series opened oil and gas channels at depths of 10,000 meters, these perforating guns not only bear the mission of energy development but also witness the rise of China’s high-end equipment manufacturing from technological breakthroughs to standard setting. In the future, with the integration of technologies such as digital pressure-controlled perforation and artificial intelligence solution design, perforation guns will continue to write a new chapter in the energy revolution deep underground.
