Abstract: A liquid well-treating chemical composition is injected into the production tubing during gas lift operations by providing a differential pressure operated valve downhole from the lowermost gas lift flow valve and maintaining sufficient liquid head of the chemical composition in the annulus to open the valve and cause the liquid chemical composition to pass into the interior of the production tubing.

Abstract: A method for producing substantially pure carbon dioxide in a single phase at the surface from a subterranean formation. A pump means, e.g., electrically driven, submergible, centrifugal pump system, is positioned downhole in a carbon dioxide production well. The carbon dioxide flows from the formation to the inlet of the pump means wherein the carbon dioxide is compressed to raise the pressure to values greater than the critical pressure of the produced carbon dioxide plus the amount of pressure that the carbon dioxide will lose due to (a) the static fluid head above the pump means and (b) flow friction from the pump means to a central processing and compression station on the surface. By so boosting the pressure within the well, the carbon dioxide will be produced at the surface at a pressure greater than the critical pressure of the produced carbon dioxide, thereby insuring the carbon dioxide will be in a single phase, supercritical state.