As the demand for oil and gas increases, the need for enhanced oil recovery, also known as EOR, and the demand of natural gas injection compressors has been on the rise. Mitsubishi Heavy Industries, Ltd. (MHI) has developed an injection compressor placing particular emphasis on reliability for handling high-pressure and high-density gas in addition to high efficiency as essential features for MHI's compressors. MHI carried out shop full load tests using natural gas at a discharge pressure of 450 bar, and demonstrated the high reliability of the compressor under the same operating conditions as those on site.