Methods and apparatus are disclosed for conveying an electrically energized hydraulic pump into a wellbore surrounded by steel casing and thereafter using that hydraulic pump to pump oil, water and gas to the surface of the earth. The apparatus may be used as a well tractor conveyance system to service a perforated steel cased wellbore located in a geological formation that incorporates means to prevent any reverse fluid flow into the geological formation through any perforations in the steel cased wellbore during movement within the wellbore of the tractor conveyance means.