Abstract: A tool for use in wells to maintain a tubed pipe filled with drilling fluid supplied by a well and to circulate the fluid through a well-pipe space, the tool facilitating sliding of tubes and producing cementation of the space. The tool can be intercalated with drilling equipment between a block and a pipe elevating arrangement for tubes that are gradually coupled to make up the casing pipe. The tool is placed between amelas extending from a rig support to adjacent the pipe elevating arrangement, the tool including a support array for positioning the tool in the drilling equipment, a positioning dynamic array to move the tool upward and downward to mate the tool on, and decouple it from, a tube, and a packaging array to, during the matings, establish a hermetic, self-adjustable elastic seal for the passage of well fluid to the inside of the tube.