Abstract: An apparatus and process for simultaneously compressing liquids and gases and exchanging the heat of compression with fluids which may be the same liquids and gasses compressed. An apparatus and process for heating maintenance fluids using heat generated when the lift gas is compressed. The compressor may be used for recovering oil and gas from a subterranean formation wherein the production rate is controlled by the gas pressure at the well head, resulting in very slow strokes or pulses and bubbles of lift gas 500 feet long or longer. It may also be used for well maintenance using cooled injection gas from the well and heated fluids, which also may come from the well and be mixed with the well gas during compression, may be conducted without interrupting production.

Abstract: An apparatus and process for lifting production fluids using the heat of compression of production gas to heat injection liquids. An apparatus and process for uninterrupted production using conserved heat of compression during well maintenance. A lift gas apparatus and process controlled by wellhead pressure. A wellhead-controlled lifting system operating during well maintenance. An apparatus for multi-phase pumping for recovering oil and gas from a subterranean formation.

Abstract: An apparatus and process for recovering oil and gas from a subterranean formation wherein the production rate is controlled by the gas pressure at the well head, resulting in very slow strokes or pulses and bubbles of lift gas up to 500 feet long. An apparatus and process for well maintenance using cooled injection gas from the well and heated fluids, which also may come from the well and be mixed with the well gas during compression, may be conducted without interrupting production. An apparatus and process for heating maintenance fluids using heat generated when the lift gas is compressed.