Compressor for gas lift operations, and method for injecting a compressible gas mixture

A gas compressor system for a wellbore, comprising:

• a multi-stage compressor comprising:
• an inlet line configured to receive a working fluid comprising a natural gas mixture, and to introduce the working fluid into the multi-stage compressor;
• a first fluid separator configured to remove liquids from the natural gas mixture at a first pressure;
• a first compressor unit configured to receive a gaseous mixture from the first fluid separator and discharge the gaseous mixture at a second pressure that is higher than the first pressure;
• a first cooler configured to receive the gaseous mixture from the first compressor unit and cool the gaseous mixture to a first cooled temperature using a fan, and then discharge the cooled gaseous mixture as a first stage;
• a second compressor unit configured to receive the cooled gaseous mixture from the first stage and discharge the gaseous mixture at a third pressure that is higher than the second pressure;
• a second cooler configured to receive the gaseous mixture from the second compressor unit and cool the gaseous mixture to a second cooled temperature also using a fan, and then discharge the cooled gaseous mixture as a second stage;
• a third compressor unit configured to receive the gaseous mixture from the second stage and discharge the cooled gaseous mixture as a third stage;
• one or more temperature sensors configured to detect a temperature of the working fluid proximate an outlet of each cooler and prior to entering a next downstream compressor unit;
• and
• a single process controller having input and output terminals and configured to:
• receive signals from the one or more temperature sensors and, in response, send signals to the first cooler and the second cooler, in real time, to adjust a flow of air through each of the first cooler and the second cooler to (i) automatically elevate temperature set points associated with first and second stage cooler discharge temperatures so as to maintain the gaseous mixture entering each of the second and third respective stages at a temperature wherein the gaseous mixture is maintained substantially in a vapor phase, and (ii) to push heat produced by adiabatic compression to the third stage.