Abstract: A travelling valve assembly utilizing a length of tubing, longer than the production screen, positioned at the end of a wash pipe and lowered into the tubing bore so that the lower end of the tubing is a depth below the production screen. When gravel packing is concluded, the tubing is then placed in position by raising the wash pipe and tubing to the upper seal bore. The wash pipe is then sheared from the tubing assembly. The tubing includes seals at each end, which seat in respective seal bores, for sealing off above and below the production screen. There is further provided a valving mechanism, such as a sliding door valve which is operable from the surface between open and closed positions. While the valving mechanism is closed, the production flow is prevented; however, upon opening the valve through a wire line or shifting tool, production flows through the sliding door valve and up to the surface through the tubing.