Reverse circulation clean out system for low pressure gas wells

摘要

The present invention provides an apparatus and a method for removing undesirable material from a well bore in a hydrocarbon formation with minimum damage to the formation. The apparatus comprises a concentric tubing string, said concentric tubing string further comprising an inner tube means having an inner annulus therethrough and an outer tube means forming an outer annulus between said outer tube means and said inner tube means, means for introducing into said well bore a pressurized clean out medium through one of the said inner annulus and outer annulus, and means for removing said material and clean out medium through the other of the said inner annulus and said outer annulus to the surface of said well bore. In a preferred embodiment, the introducing means comprises a discharge compressor or mud pump and the removing means comprises a suctioning compressor.