Paper: APPLICATION OF CHEMICAL CONCENTRATES TO WELL ANNULUS VIA HIGH QUALITY, LOW LIQUID VOLUME FOAM

A method has been developed and successfully applied to generate a high quality foam with nitrogen and concentrated chemical for treating down the annulus. The advantages of the foam method are that the total liquid volume required to completely fill the annular space of a well is very small compared with the bulk volume of the foam. The low hydrostatic loading does not adversely affect production. The chemical can be applied in a concentrated form which favors faster and more complete adsorption onto reactive surfaces After application to the annulus the foam breaks leaving a thin liquid film on the tubing and casing and excess chemical drops to the standing liquid level and is available to coat the inside of the tubing during normal production. This method is being successfully applied in low-pressure coal bed methane wells.