Body of perforating gun represents a piece of pipe with inner trapezoid threads of ACME-2G type which serve to interconnect cumulative perforating guns by connecting bodies. There are round grooves of a certain length on the outer surface. They are concentrators of stress and serve for ‘directed’ release of the charge into body of rock to be destroyed. Bodies of cumulative perforating gun systems are manufactured from a seamless pipe of steel grade 4130 (an equivalent of grade 30ХМА) with high level of purity and niobium-micro-alloyed, which determines their high corrosion resistance and high mechanical properties in combination with high ductility.
Perforating guns are manufactured in various modifications (length and number of milling cuts), depends on a customer’s requirements. Besides, finished perforating gun systems are subject to a mandatory random inspection to verify proper quality of perforating gun system by physical explosion method.
| Steel grade | Mass fraction of elements, % | |||||||
| C | Mn | Si | P | S | Ni | Cr | Mo | |
| No more | ||||||||
| 4130 | 0,28-0,33 | 0,40-0,60 | 0,15-0,35 | 0,015 | 0,005 aim to 0,003 | 0,30 | 0,15-0,25 | |
| Properties | Values |
| Yield strength (0,2 % the method to evaluate yield strength by set residual deformation), MPa (ksi) | 930 – 1080 (135– 157) |
| Tensile strength, MPa (ksi), at least | 965 (140) |
| Sharpy impact test min., J | 89,5 |
| Elongation before rupture in 4D, %, at least | 15 |
| Minimal hardness, HRC | 31 |
| Forms of inclusions | Maximal allowed level, number | |
| Thin series | Thick series | |
| A | 0 | 0 |
| B | 1,0 | 0,5 |
| C | 0,5 | 0 |
| D | 1 | 1,0 |
Representatives of Technical control dpt. make quality control in all production steps using the most modern and highly precise measuring instruments: - feedstock and components used for production are subject to 100% incoming inspection to verify conformity with relevant technical and operational characteristics; - in the course of production, at each step of the manufacturing process, articles are subject to random selection and their conformity with technical characteristics is verified; - bodies are 100% inspected; - technical control service makes a final technical acceptance.
Single use cumulative perforating gun systems are designed for secondary penetration in to productive beds in oil, gas and other horizontal and directionally inclined wells. Cumulative perforating gun systems are used to address special geologic-engineering challenges, where it is necessary to penetrate the beds using phasing 0°, 45°, 60°, 90° and 180° and self-orientation of charges under necessary angle in relation to a set interval of the bed. Frame with charges inside a body of perforating gun orientates by means of specially designed rotation unit.