Oil and gas extraction
Until recently it has been a common practice in oil fields to flare associated petroleum gas resulting from the initial treatment of crude oil prior to transportation by pipeline. In accordance with Russian regulations 95% of associated petroleum gas must be processed before 2011. For this purpose the gas has to be compressed. Working discharge pressures of the compressors installed in oil fields are generally within 20 to 50 bar. Reciprocating gas engine-driven compressors are typically employed for this purpose. The typical power rating of a single compressor set is 150 to 3,500 kW. Compressor drive is usually fueled by the transported gas. In some cases associated petroleum gas may contain hydrogen sulfide, and sometimes its content may be quite significant (up to 6%). This requires a special configuration of gas flow path in the compressor and the drive. AJAX integral engine-compressors can run on poor quality fuels and maintain a factory warranty with up to 3% H2S with appropriate engine treatment options that are available. For these reasons plus the high flexibility of Ajax units across wide operating pressure ranges, Ajax is an optimum solution for small and medium-sized oil fields.
Another application for compressors in oil field facilities is the gas re-injection for the purpose of reservoir pressure maintenance. Associated gas, or sometimes air, may be used for re-injection. Compressor working pressure for these applications is 150 to 350 bar. A series compressor system represents an innovative solution, where or sometimes air, may be used for re-injection. Compressor working pressure for these applications is 150 to 350 bar. A tandem compressor system represents an ingenious solution, where centrifugal air compressors are used for initial compression, and reciprocating compressor is used for further compression to the required pressure.
The gas lift production method is often used in long-operated oil fields to increase well production by intensifying oil flow into the tubing by injecting gas in the reservoir through another well. Compressors with working pressures of 150-350 bar are used for this purpose. Associated gas is most frequently used as the injection medium.
In natural gas fields, compressors are often required to maintain or increase gas flow into the pipeline system, since well flow and reservoir pressure tend to decrease over time. Reciprocating (in small and medium-size fields) and centrifugal (in large fields) compressors are used for these applications.