From Lifting to Maintenance: Key Lifecycle Operation and Maintenance Points for Wellhead Gas Compres

　　The installation quality and operation & maintenance level of a Wellhead Gas Compressor directly affect the unit's service life and production safety. From foundation construction to daily maintenance, every step must follow standardized procedures.

I. Core Steps for OnSite Installation

Foundation & Vibration Isolation

　　The compressor foundation shall be poured on solid undisturbed soil or properly compacted ground, with a bearing capacity ≥5–10 t/m² as required. The reinforced concrete foundation shall have a minimum thickness of 200 mm, and the embedded anchor bolts shall be positioned within a deviation of ≤±2 mm. Vibration isolators (e.g., spring or rubber pads) shall be installed between the unit and the foundation, with deflection controlled at 70%–80% of the rated value to reduce lowfrequency vibration transmission.

Piping & Leak Tightness Testing

　　Suction and discharge piping shall be seamless steel tubes with internal rust removal to Sa2.5 level. Flow velocity shall be kept ≤15–20 m/s to minimize pressure loss and noise. Flange alignment deviation shall be ≤0.5 mm/m; forced mating is strictly prohibited. After installation, a strength test at 1.5 times the maximum working pressure (hold for 30 min) and a leak tightness test at 1.05 times the working pressure (using leak detection fluid or electronic detector) shall be performed. Before putting into service with natural gas, the system shall be purged with nitrogen until the oxygen content is <2 vol%.

Electrical & Control System Wiring

　　Power cables and control cables shall be routed separately to avoid electromagnetic interference. The PLC (or dedicated controller) shall undergo pointtopoint commissioning to verify alarm and shutdown logic, including low inlet pressure, high discharge pressure, low lubricating oil pressure, etc. The emergency stop button must be able to interrupt the power circuit under any condition.

II. Daily Operating Monitoring Parameters

Vibration

　　At the crankshaft bearing and cylinder positions, vibration velocity (RMS) shall be measured according to ISO 10816. For reciprocating compressors, normal value ≤11.2 mm/s; >18 mm/s requires shutdown and repair.

Temperature

　　Discharge temperature: ≤160°C (reciprocating) or ≤120°C (screw). Lubricating oil temperature: 45–75°C. Cooling water temperature difference across the cooler: 5–10°C.

Pressure

　　Deviation of suction and discharge pressure at each stage shall not exceed ±5% of design values. Abnormal interstage pressure indicates valve leakage or piston ring wear.

Lubricating Oil Level

　　Maintain at the middle line of the sight glass. Take oil samples periodically to analyze viscosity, water content, and acid number.

Alarm & Shutdown Logic Check

　　Simulate each safety protection point weekly (e.g., low inlet pressure, high discharge pressure, high temperature, low oil pressure, motor overload) to confirm that alarms and shutdowns function correctly.

III. Scheduled Maintenance Plan

Daily

　　Check oil level, coolant level, and gas leaks; record suction/discharge pressure and temperature; listen for abnormal noises.

Weekly

　　Clean the air filter; check all bolted connections; drain condensate from gasliquid separators.

Monthly

　　Change lubricating oil (first change after the first month of operation, then every 500–1000 operating hours); adjust belt tension or coupling alignment; test safety valves.

Quarterly

　　Replace suction/discharge valve assemblies; measure cylinder clearance volume; clean cooler cores; calibrate instruments.

Consumable Replacement Intervals

　　Valve plates (reciprocating): 4,000–6,000 hours or when flow drops / interstage pressure becomes abnormal.

　　Piston rings: 8,000–10,000 hours (if cylinder wear exceeds 0.1 mm, rebore and fit oversized rings).

　　Seals (packing rings, Orings): every 6,000 hours or when oil/gas leakage appears.

　　Oil filter element: replace with each oil change.

IV. Rapid Diagnosis of Typical Faults

Insufficient Flow

　　Possible causes: clogged air filter, leaking valve plates, worn piston rings, excessive clearance volume. Actions: clean filter element; check valve assembly sealing; measure cylinder pressure; adjust clearance shims.

Abnormal Noise

　　Metallic knocking: excessive crossheadshoe clearance, loose connecting rod bearing shell, piston hitting cylinder head. Immediate shutdown and adjustment / bearing replacement required.

　　Highpitched squeal: broken valve spring or valve plate flutter – replace valve assembly.

Overheating

　　High discharge temperature: insufficient cooling water, fouled interstage cooler, excessive compression ratio. Actions: check cooling water circuit; clean cooler; verify bypass valve not open unintentionally.

　　Bearing overheating: degraded oil or blocked oil passage – change oil and clean oil passage.

Gas Leakage

　　Leaks at flanges, valves, or packing case: locate with leak detection fluid, tighten bolts or replace seals. For severe leaks, shut down and depressurize before handling.

V. Safety Operating Code

Natural Gas Leak Emergency Procedure

　　When a flammable gas concentration reaches 10% of the lower explosive limit (LEL), immediately:

　　① Cut off compressor power (remote or local emergency stop).

　　② Close suction and discharge valves.

　　③ Start the ventilation system (if indoors).

　　④ Evacuate to an upwind location and report to the control room.

　　⑤ After the concentration drops to a safe level, enter with an airbreathing apparatus to locate the leak source.

NoFire Zone & Personal Protective Equipment (PPE)

　　Smoking, hot work, and carrying nonexplosionproof electronic devices are strictly prohibited within a 15 m radius of the compressor unit. Onsite personnel must wear antistatic workwear, hard hat, safety glasses, and steeltoe work boots. During highpressure gas operations or leak testing, add a face shield and impactresistant gloves. Before any maintenance, depressurize the unit and follow lockout/tagout procedures.

VI. Summary

　　Neglect at any stage – from foundation vibration isolation to fault handling – can lead to unplanned shutdowns or safety incidents. Establishing a standardized inspection checklist, strictly following consumable replacement intervals, and reinforcing emergency drills can significantly improve compressor reliability and lifecycle costeffectiveness. For remote well sites, remote monitoring and online vibration analysis systems are recommended to progressively achieve predictive maintenance.