PDM Drill Bearings - Parts

1

9LZ95

High-carbon chromium bearing steel (GCr15), heat-treated to HRC 60-64, with a corrosion-resistant chrome plating and sealed with nitrile rubber (NBR) to prevent downhole fluid intrusion

1. Abrasive wear from sand, rock particles, and drilling fluid contaminants; 2. Corrosion from acidic downhole fluids (H₂S, CO₂); 3. Seizure due to insufficient lubrication in high-temperature environments

1. Use only API-certified drilling lubricants (ISO VG 68) to ensure adequate lubrication; 2. Inspect the bearing seal before use to check for cracks or damage; 3. Avoid operating in downhole temperatures exceeding 150°C to prevent seal deterioration

2

LZ95

High-carbon chromium bearing steel (GCr15), heat-treated to HRC 60-64, with a ceramic coating on the raceway for enhanced wear resistance and NBR seals

1. Raceway wear from high-speed rotation and debris impact; 2. Seal damage from mechanical impact during drill tripping; 3. Fatigue failure from long-term cyclic loading in directional drilling

1. Handle the bearing with care during transportation and installation to avoid impact damage; 2. Replace the seal annually or after every 500 hours of operation; 3. Monitor downhole vibration and adjust drilling parameters if vibration exceeds 5g

1

BH5LZ120-7.0

Stainless steel (440C) with a titanium nitride (TiN) coating, heat-treated to HRC 62-66, equipped with double-row raceways and fluoroelastomer (FKM) seals for high-temperature resistance

1. Double-row raceway wear from high radial and axial loads in deep wells (3000-5000m); 2. Coating peeling due to excessive downhole vibration; 3. Corrosion from high-salinity downhole fluids

1. Conduct a pre-installation load test to ensure compatibility with the PDM drill’s rotor; 2. Apply anti-corrosion grease to the bearing surface before installation; 3. Limit continuous operation time to 800 hours to avoid fatigue failure

2

5LZ120

High-carbon chromium bearing steel (GCr15SiMn), heat-treated to HRC 60-64, with a polished raceway for reduced friction and NBR seals for fluid protection

1. Friction-induced wear from inadequate lubrication; 2. Debris buildup in the raceway leading to scratching and seizure; 3. Fatigue cracking from cyclic loading in horizontal drilling sections

1. Flush the bearing with clean lubricant before installation to remove any debris; 2. Monitor lubricant condition weekly and replace if it becomes contaminated with sand or metal particles; 3. Avoid sudden changes in drilling speed, which increase cyclic loading

3

5LZ165

Ceramic hybrid material (silicon nitride ceramic balls + GCr15 raceways), heat-treated to HRC 62-66, FKM seals, and a steel cage for high-speed stability

1. Ceramic ball wear from impact with hard rock particles; 2. Steel cage deformation from high torque in large PDM drills; 3. Seal leakage due to extreme downhole pressure (exceeding 80MPa)

1. Use a torque wrench to ensure proper installation torque (45-50 N·m); 2. Inspect the steel cage for deformation every 300 hours of operation; 3. Operate within the recommended pressure range (≤80MPa) to prevent seal leakage

1

5LZ165x7Y

Nickel-chromium alloy (Inconel 718) raceways + silicon nitride ceramic balls, heat-treated to HRC 64-68, FKM double seals, and a reinforced steel cage

1. Alloy raceway wear from high-temperature oxidation (above 160°C); 2. Ceramic ball chipping from impact with hard formation debris; 3. Seal degradation from exposure to H₂S and CO₂

1. Preheat the bearing to 50-60°C before installation to improve fit; 2. Use H₂S-resistant lubricants in sour gas wells; 3. Replace the bearing if downhole temperature exceeds 180°C for more than 2 hours

2

5LZ172x7Y

High-strength bearing steel (GCr18Mo) with a diamond-like carbon (DLC) coating, heat-treated to HRC 62-66, FKM seals, and a ceramic cage for reduced friction

1. DLC coating wear from abrasive drilling fluids; 2. Ceramic cage cracking from mechanical impact during drill tripping; 3. Fatigue failure from long-term high-speed rotation (above 1200 RPM)

1. Avoid dragging the bearing across rough surfaces during installation; 2. Limit drilling speed to ≤1200 RPM to prevent cage damage; 3. Inspect the DLC coating for scratches before each use, replace if coating is peeled

3

5LZ197x7Y-III

Titanium alloy (Ti-6Al-4V) raceways + zirconia ceramic balls, heat-treated to HRC 65-69, FKM/Viton composite seals, and a titanium cage for ultra-high strength

1. Titanium raceway corrosion from high-salinity, acidic downhole fluids; 2. Zirconia ball wear from prolonged contact with hard formations; 3. Composite seal leakage from extreme pressure (above 100MPa)

1. Conduct a corrosion resistance test before using in sour or high-salinity wells; 2. Apply a protective coating to the raceways every 400 hours of operation; 3. Operate within the recommended pressure range (≤100MPa)

4

5LZ197

High-carbon chromium bearing steel (GCr15) with a chrome plating, heat-treated to HRC 60-64, NBR/FKM dual seals, and a steel cage for stability

1. Chrome plating peeling from mechanical impact; 2. Dual seal damage from improper lubrication; 3. Raceway wear from debris buildup in ultra-deep wells (5000m+)

1. Use only compatible lubricants to avoid seal damage; 2. Clean the bearing thoroughly after use to remove downhole debris; 3. Inspect the chrome plating for peeling, replace if damage covers more than 5% of the surface

1

12808K

High-strength bearing steel (GCr18) with a TiN coating, heat-treated to HRC 62-66, FKM seals, and a reinforced steel cage for high torque resistance

1. Steel cage deformation from high torque (above 5000 N·m); 2. TiN coating wear from abrasive hard rock particles; 3. Raceway seizure due to insufficient lubrication in high-temperature environments

1. Monitor torque levels during drilling, adjust parameters if torque exceeds 5000 N·m; 2. Use high-temperature lubricants (up to 200°C) in harsh environments; 3. Inspect the steel cage for deformation every 200 hours of operation

2

128811K

Ceramic hybrid material (alumina ceramic balls + GCr15 raceways), heat-treated to HRC 64-68, FKM dual seals, and a ceramic cage for reduced friction and high torque resistance

1. Alumina ceramic ball chipping from impact with hard rock; 2. Ceramic cage cracking from sudden torque spikes; 3. Dual seal leakage from downhole fluid contamination

1. Avoid sudden starts/stops of the PDM drill to prevent torque spikes; 2. Clean the bearing and replace lubricant after drilling in fractured formations; 3. Inspect ceramic components for chipping before each use, replace if damaged

What type of lubricant should I use for these PDM drill bearings?

Use only API 7-1 certified lubricants, preferably ISO VG 68 or VG 100. For high-temperature environments (above 150°C), use high-temperature lubricants (e.g., synthetic polyalphaolefin). Avoid mixing different lubricant types, as this reduces lubrication performance and damages seals. For sour gas wells, use H₂S-resistant lubricants to prevent corrosion.

How often should I replace PDM drill bearings, and what factors affect their service life?

Service life varies by model and operating conditions: LZ Series (9LZ95, LZ95) last 500-800 hours; 5LZ basic models (5LZ120, 5LZ165) last 800-1200 hours; 5LZ enhanced models (5LZ165x7Y, 5LZ197x7Y-III) last 1200-1500 hours; specialized models (12808K, 128811K) last 1000-1300 hours. Factors affecting life: downhole temperature/pressure, debris content, lubrication quality, and drilling parameters.

Can I use non-OES bearings to replace worn PDM drill bearings, and what are the risks?

No—always use genuine OES bearings. Non-OES bearings do not meet API 7-1 standards or the specific load/temperature requirements of PDM drills. Risks include premature seizure, raceway wear, seal leakage, and costly downtime. Non-OES bearings may also damage the PDM drill’s rotor, leading to more expensive repairs and voiding the drill’s warranty.