The non-magnetic drill collar is made of low chromium manganese alloy steel, which is forged through strict chemical composition analysis. All non-magnetic drill collars produced from Sunrise Petro have been tested for mechanical properties to ensure that their hardness, toughness, impact value and corrosion resistance meet the standards, with good low magnetic permeability and good machining performance.
The non-magnetic drill collar manufactured from Sunrise Petro is made of stainless alloy steel with low magnetic permeability, and the cross-section of the pipe body is round.
The structure of non-magnetic drill collars is the same as that of ordinary drill collars, but their chemical composition and mechanical properties are different from those of ordinary drill collars. Nonmagnetic drill collar is a kind of drilling tool with special functions in directional well engineering. When the magnetic inclinometer is used to measure the inclination and azimuth of the borehole in directional wells, in order to protect the compass from the magnetic field of the drill string, a certain length of non-magnetic drill collar must be equipped in the drill string, so that the magnetic inclinometer can be located at a suitable position in the non-magnetic drill collar to measure the inclination, otherwise the correct measurement results cannot be obtained.
Parameters
Permeability (magnetic field strength = 1 × 105/4πNm) :
Maximum value: 1.010, average value: μ r≤1.005 。
Magnetic field gradient: (hot spot) maximum value: B ≤ 0.05
| OD range | Yield strength | Tensile strength | Elongation | Hardness | Charpy impact energy | |
| mm | in | MPa | MPa | % | HB | J |
| 79.4～171.4 | 3 1/8～6 3/4 | ≥758 | ≥827 | ≥18 | NA | NA |
| 177.8～279.4 | 7～11 | ≥689 | ≥758 | ≥20 | NA | NA |
Features
1) API pin stress relief groove and box boreback
An API pin stress relief can be used on all drill collars and downhole tools. It is a recommended option in situations where fatigue can occur as a result of bending. By removing unengaged threads in the high stress areas of the drill collar connection, it is less likely to crack due to fatigue because the bending will take place in the area of the connection with smooth surfaces that are free of stress concentrations.
2) Internal bore treatment
This option generates a compression level of at least 60,000 PSI at a given depth. This provides the collar with an excellent resistance to stress corrosion cracking.
3) Flexing
An optional outside profile can be machined to reduce the collar rigidity if required.
4) Elevator and slip recesses
Optional slip and elevator recesses are available to improve handling and safety. These two features can be used together or separately.
Sunrise Petro manufactures a variety of drilling pipes for oilfield including the common drilling pipe, Kelly bar, drill collar, anti-corrosion and anti-abrasion drill pipe according to API 5DP and API 7-1. These drilling pipes have diverse types to fit different environments and applications.
The company has an R & D center with a team composed of domestic authoritative professors and senior engineers to provide users with high-performance and practical products.
