Surface-Driven Progressing Cavity Pump Application in Coalbed Methane Wells (1500–2000 m Depth, 8–15 m³/day Water Production)
Rubber Material Selection for Stator Liners
The stator rubber is critical for pump durability. In Shanxi’s CBM wells (1500–2000 m depth, 8–15 m³/day water production), HNBR (Hydrogenated Nitrile Butadiene Rubber) is preferred due to its:
- Anti-Gas Invasion Resistance: Prevents swelling from high gas content.
- Anti-Abrasion Performance: Withstands coal fines (0.1–0.5 mm) with hardness Shore A 75 ± 2.
- Temperature Adaptability: Stable up to 120°C.
- Service Life: 12–18 months (longer than NBR).
Recommended PCP Model Selection
GLB120-14 (1500–1800 m depth, 8–15 m³/day water):
- Pump diameter: 120 mm, Stator stages: 14 (140 m lift/stage).
- Motor power: 15–22 kW (18.5 kW for 1500 m, 22 kW for 1800 m).
- Advantages: Balanced performance, low torque, cost-effective maintenance.
GLB200-27 (1800–2000 m depth, 10–20 m³/day water):
- Pump diameter: 200 mm, Stator stages: 27 (270 m lift).
- Motor power: 22–37 kW (30 kW for 1800 m, 37 kW for 2000 m).
- Advantages: Ideal for deeper wells, enhanced gas-handling, longer service life.
Motor Configuration
- GLB120-14: 15–22 kW motor with VFD (Variable Frequency Drive) for speed optimization (200–300 RPM).
- GLB200-27: 22–37 kW motor with overload protection (thermal sensors).
- Energy Efficiency: VFD reduces power consumption by 15–25%.
Operational Practices
- Installation: Centralizers every 3–5 tubing joints, anchor tools to prevent pump movement.
- Maintenance: Replace stator every 12–18 months, monitor current/torque daily.
- Troubleshooting: Gas lock (install gas separator) or coal fines accumulation (use screen filters).
