A removable automatic insertion device with segmented drainage shaft may be used to remove unwanted liquids from pipelines, tanks and other pressurized vessels. The insertion device inserts and withdraws the drainage shaft, one segment at a time into the pipeline or other pressurized vessel. A termination assembly is connected to the subsurface end of the drainage shaft and includes a normally closed drainage valve assembly. After insertion of the drainage shaft, the automatic insertion device is removed and a surface mounted discharge assembly is connected to the drainage shaft. To open the drainage valve assembly and commence drainage of unwanted liquids, pressurized fluid is injected through the discharge assembly, and a segmented hollow actuation tube to open the subsurface drainage valve assembly. Unwanted fluids then pass through the open drainage valve assembly, the drainage shaft to the surface mounted discharge assembly.