Abstract: The invention relates to a method and apparatus for avoiding fluid loss during installation of a lower completion in an open hole oil, gas or water well. A lower completion assembly 3, 33 comprising tubing with production perforations, for example in a sand screen, is run into the well on drill pipe 8, 38. The lower completion 3, 33 is hung from a packer 4, 34, together with a wash pipe 9, 39 which extends through the inner of the lower completion 3, 33. At the proximal end of the lower completion is a seal 15, 45 through which the wash pipe 9, 39 extends. An aggressive breaker fluid is circulated through the wash pipe, through a float shoe 11, 41 at the end of the completion. Once circulation is completed, the aggressive breaker removes all filter cake from the formation in 30 minutes. The wash pipe 9 is withdrawn but, because the wash pipe 9 seals against the seal 14 as it is withdrawn, fluid is not lost into the formation via the lower completion.