The Forensic expert kollegium carries out expertise of drilling equipment that is used in various sectors of the economy (mining, construction of underground structures, underground communications) to ensure the process of destruction of soil and rocks.
During operation, parts and tools of drilling equipment experience increased physical wear, as well as dynamic, thermal stress, which leads to equipment failures.
Based on the expert practice of the Forensic expert kollegium, the most common reasons for failure of drilling equipment are:
1. Violations of the operating rules:
- exceeding the permissible loads;
- using the drilling equipment for other purposes (for example, usage in geological conditions not provided for in the design and operational documentation);
- insufficient exploration work;
- inadequate analysis of oncoming communications (water supply and heating pipes, sewer pipes, sleeves (pipes) of power or communication cables, wells) during horizontal drilling in urban conditions;
- untimely maintenance or repair;
- unskilled personnel actions.
2. Manufacturing and construction defects:
- insufficient strength or wear resistance of the tool;
- inadequate quality of the material used in the production;
- improper manufacturing of parts and assemblies:
- unacceptable deviation from the straightness of the axis, deviation from the profile of the longitudinal section, deviation from the outer diameter or difference in thickness of drill pipes or upsetting on them;
- inadmissible deviations of thread parameters of the inner or outer surfaces of the tool joints prior to assembly;
- incorrect positioning of cutters (carbide inserts) on drill bits;
- inadequate welding of legs to multi-cone sectional bits;
- inadmissible deviations in the location of cutters (teeth) or cones relative to the nominal end surface of the drill bit;
- improper heat treatment of abrasive-cutting, cutting-shearing, crushing or crushing-shearing tools;
- inadequate manufacturing quality of the roller cone bearing assembly;
- improper welding of tool joints to drill pipes;
- errors in the development of the design of the working bodies of the equipment:
- failure to ensure the required rigidity of the working body;
- irrational arrangement of abrasive-cutting, cutting-shearing, crushing or crushing-shearing tools, which does not ensure even wear of the working tool;
- inadequate design of units for supplying water, drilling mud or lubrication of units of the working body;
- improper design of the roller cone bearing assembly;
- improper selection of the power of the working body drive;
- improper design of the gearbox of the working body drive;
- insufficient safety factor of the elements of the working body, drill pipes.
3. Natural physical wear of equipment.
4. Collapse of the rock due to the presence of cavities in the rock or due to erosion of the lower layers of the rock by groundwater.
The expertise of drilling equipment is carried out by qualified and duly certified specialists in non-destructive testing (visual, capillary, ultrasonic methods), as well as experts in the field of metallurgy and mechanical engineering.
During the expertise of drilling equipment, a complete analysis of the operational and design documentation is carried out. Based on the data obtained, the choice of means and schemes of measurements and tests is made, which, depending on the task, may include:
- measurement of the geometric parameters of the installation;
- measurement of the geometric parameters of the working body (drill bits, crowns, the size and location of cutters and teeth made of carbide plates);
- examination of destruction in the zone of welded seams or in the heat-affected zone (in the presence of such destruction);
- examination on the presence of surface and internal cracks in fatigue failure;
- research of design features and operation of units and assemblies;
- disassembly of drive gearboxes, bearing assemblies, sectional drill bits (if necessary).
Further, the selection of samples of parts is carried out to determine the physical and mechanical properties of the material in laboratory conditions (in some cases, it is possible to determine the physical and mechanical properties by express methods at the inspection site). If necessary, computer modeling and calculation of strength, contact strength and wear resistance are performed using the finite element method.
During the expertise of drilling equipment, the experts of the Forensic expert kollegium are asked the following questions:
- to determine the reason for the failure of the drilling equipment;
- to determine the nature of the identified defects;
- to determine the possibility of eliminating the existing damage;
- to determine the list of damaged units;
- to determine the cost of refurbishment of equipment.
You can consult the Forensic expert kollegium on the expertise of drilling equipment at: Minsk, Zhukovskogo st., 11A, 4th floor
or by phone: +375 (17) 317 04 71; +375 (17) 317 04 72; +375 (17) 317 04 73; +375 (17) 317 04 74; +375 (17) 317 04 75; +375 (17) 317 04 76; +375 (29) 656 60 11; +375 (44) 588 60 11
