Gas Liquids Engineering Ltd. (GLE) designed a high-volume (250 MMSCF/d) high-pressure (9000 psia) sour gas (16% H2S, 5% CO2) injection scheme to maintain the reservoir pressure and enhance the oil recovery from the Tengiz field in Kazakhstan. GLE generated methods for estimating physical properties and phase equilibria encountered in the injection scheme. After several years of sour gas re-injection, a Sulphur plant designed by others was constructed.