GB914591A - Well tubing plug - Google Patents

Abstract

914,591. Wells. FREDD, J. V. April 13, 1959, No. 12512/59. Class 85. A well tubing plug comprises a central body 11, a seal 13 carried by the body, dogs 25 having limited longitudinal movement relative to the body, stop shoulders 28 on the dogs engageable upon upward movement of the body with the ends 40 of recesses 42 in the tubing 37 when the dogs are expanded. and inclined surfaces 29 adapted to engage the ends 41 of the recesses to retract the dogs as the plug is moved downwardly in the tubing. The plug is lowered into the tubing by a running tool 43 until the dogs reach a recess where a surface 31 on an expander 15 slidable on the body causes the dogs to enter the recess. When the recess is reached where it is desired to set the plug, the body is pulled upwardly forcing the seal which is carried by the expander to engage the tubing and locking the dogs against retraction (see Fig. 2). Further upward pull shears a pin 47 so that the tool 43 may be removed. The plug is removed by pushing it downwardly out of the tubing. Fig. 10 shows a modification in which the seal 100 is fixed to the central body 80, and the dogs 83 are biased outwardly by springs 85. The dogs are held in their expanded position against the lower part of the tubing 112 by bosses 91 on the body which engage cutaways 93 in the dogs. The plug has a valve 104 which permits downward flow past the seal. In the modification shown in Fig. 12, seals 141, 144 are slidably carried by the central body 115 which carries a sleeve 147 adapted to expand the seal 141. The dimensions of the projecting part of the dogs may correspond to those of a recess.