The invention relates to a double string slurry pump for pumping liquids to the surface of a hydrocarbon well and especially a hydrocarbon well that is producing both natural gas and liquid fluids. The double string slurry pump includes a hollow tube that raises and lowers the plunger and carries the liquids to the surface and an outer tube receives liquids down into the well to periodically flush area around the pump to stir up particles and fines for conveyance out of the wellbore with the liquids. The additional conduit for flushing may be used to provide biocides, solvents or other treatments including with liquids at elevated temperature to create desired results or changes downhole. Moreover, the additional conduit may be provided with ports to provide access to the interior of the gas production path to provide such treatments above the well. The natural gas is produced through the annulus between wellbore casing and the outer production tubing string.