The Essential Role of Compression Systems in Natural Gas Processing Facilities

Serge Jean
Jul 16
3 min read

Natural gas travels thousands of miles from remote wellheads to reach consumers. Yet, it cannot move on its own through pipelines due to its highly compressible nature. To keep gas flowing smoothly, compression systems provide the mechanical energy needed to raise pressure, overcome friction losses, and push gas through various processing stages. These systems form the mechanical heart of gas processing facilities, directly influencing throughput, reliability, and efficiency.

This article explores how compression systems operate within natural gas facilities, the types of compressors used, and why proper control systems are critical for safe and efficient operation.

How Compression Systems Enable Gas Transport

Natural gas extracted from underground reservoirs often starts at low pressure. To move it through pipelines and processing units, the gas pressure must be increased continuously. Compression systems perform this vital role by:

Raising gas pressure to overcome resistance in gathering networks and pipelines
Driving gas through treatment units such as dehydration and separation systems
Boosting pressure of treated gas for long-distance transmission to end users

Without these systems, natural gas would not flow efficiently, leading to bottlenecks and reduced production rates.

Three Key Applications of Compression Systems

Compression systems are deployed at different points in a gas facility, each serving a specific purpose:

1. Wellhead or Booster Compression

At the wellhead, compressors pull gas from low-pressure, depleting reservoirs. These compressors raise the pressure enough to push gas into the gathering network. This step is crucial for maintaining steady production as reservoir pressure declines over time.

2. Process Compression

Within the processing plant, compressors move gas through various treatment stages. These include:

Treating units that remove impurities
Dehydration beds that eliminate moisture
Low-temperature separation systems that separate liquids from gas

Process compressors ensure gas meets quality standards before export.

3. Sales Gas or Export Compression

After treatment, sales gas compressors raise the pressure of sweet, treated gas to very high levels, often exceeding 1,000 psi. This high pressure is necessary to push gas into long-distance transmission pipelines that deliver it to markets.

Types of Compressors Used in Gas Facilities

Engineers select compressors based on flow rates and pressure requirements. The two main types are centrifugal and reciprocating compressors.

Centrifugal Compressors

These dynamic machines use high-speed rotating impellers to add kinetic energy to the gas. The gas then passes through a diffuser where kinetic energy converts into pressure. Centrifugal compressors are well-suited for:

Handling large volumes of gas continuously
Operating with minimal vibration
Applications requiring moderate pressure increases

They are common in process and export compression where steady, high-volume flow is needed.

Reciprocating Compressors

Reciprocating compressors use pistons moving inside cylinders to mechanically reduce gas volume and increase pressure. They excel at:

Handling lower gas volumes
Achieving very high pressure ratios in a single stage
Applications where precise pressure control is critical

These compressors are often found at wellheads or booster stations where gas volumes are smaller but pressure boosts must be significant.

Importance of Anti-Surge Control Systems

A major engineering challenge in compressor operation is preventing surge—a condition where flow reverses or becomes unstable, potentially damaging equipment. Anti-surge control systems monitor compressor performance and adjust flow or speed to avoid surge events.

These control systems: