1. Basic principles for selecting hardfacing
l To ensure good wear resistance and better protect downhole tools such as drill pipe joints, weighted drill pipes, and drill collars. The surface hardness of the wear-resistant belt should not be lower than HRC55.
l When drilling in the casing, in order to protect the casing and reduce its wear, the selected wear-resistant belt should have good anti friction performance.
l A scientifically reasonable balance between wear resistance and friction reduction.
l Generally, it is recommended to use hardfacing with a “raised” shape, and not recommended to use hardfacing with a “flat” shape. Only when the maximum outer diameter of the drill pipe joint is limited to avoid interference with the inner diameter of the casing, is it recommended to use a “flat” shaped wear-resistant strip. Any type of wear-resistant strip welded in this way cannot produce the maximum wear-resistant effect because both the outer diameter of the drill pipe joint and the wear-resistant strip are being worn at the same time.
2. Common misconceptions in choosing hardfacing
Misconception 1: Tungsten carbide wear-resistant belt is the best wear-resistant belt used to protect drill rods
After the tungsten carbide wear-resistant strip is welded onto the drill pipe joint, the sharp tungsten carbide particles cause micro cutting on the casing, resulting in severe casing wear.
Many foreign oil companies have internal standards that explicitly prohibit the use of tungsten carbide hardfacing. Some domestic oil fields also prohibit their use.
NS-1 standard
Internal standards of P Oil Company in the UK
Misconception 2: Choosing hardfacing that excessively pursue friction reduction and sacrifice wear resistance
l In order to protect the casing and reduce its wear, excessive pursuit of the anti friction performance of the wear-resistant belt sacrifices its wear resistance.
ü The wear-resistant belt is easily worn out, causing direct contact between the drill pipe joint and the casing or formation wellbore. As is well known, the wear between the bare drill pipe joint and the casing or formation wellbore is much greater than that of the drill pipe joint with the wear-resistant belt, resulting in severe wear of the casing and early failure of the drill pipe due to excessive wear.
ü The short service life of hardfacing increases their usage costs.
Post time: Sep-10-2024
