Quality appraisal of drilling collar

Drill collar is a kind of seamless steel pipe with thicker wall and larger weight per unit length than ordinary drill pipe. It is made of high-strength steel and is used for drilling, crushing or salvage operations underground. The working principle of
drill collar is to push it into the ground or rock through its sharp tapered front end, and then rotate it deeply through the hard formation to achieve the purpose of drilling or releasing.
In the case of drill collar quality appraisal, Zhongke Testing can provide drill collar quality appraisal services.

1. Plasma drill collar: Using high-energy plasma as the power of the drill collar, it can drill into particularly hard and difficult-to-drill formations;
2. Mechanical drill collar: Using mechanical principles to drive the drill bit, the drill collar has a simple structure and is suitable for Shallow formations;
3. Hydraulic drill collar: uses hydraulic pressure to drive the drill bit, suitable for drilling in deep formations;
4. Expanded drill collar for drilling: increases the length of the drill pipe, expands the drilling radius, and is suitable for formations that require drilling into large-diameter wellbores.

SY/T 5144-2013 Drill collar
DZ/T 0109-1994 Drill collar for hydrological water well drilling
SY/T 5369-2012 Management and use of oil drilling tools Kelly pipe, drill pipe, drill collar

An engineering company purchased a batch of drill collars for drilling wells. During use, the drill collars broke one after another and failed to work properly, delaying the project date.
was entrusted by a court to conduct appraisal and analysis on the drill collars involved in the case that "continuously broke and were unable to work properly."
quality analysis results:
The quality analysis expert group discussed the relevant information and on-site investigation and inspection of the drill collars involved in the case and conducted a comprehensive quality and technical analysis, and made the following suggestions and conclusions:
The threads and outer layers of this batch of drill collars were welded, and they were broken due to huge torque forces during the construction process.
The manufacturing process of this batch of drill collars does not comply with relevant national standards.