Subsurface transient pressure testing apparatus and method of use thereof

Claim 1

Apparatus for seating in a seating nipple in a well tubing string for use in temporarily shutting off fluid flow through the tubing at a subsurface location in a well and making pressure determinations below the plug comprising: a. a main plug body having a passageway therethrough, said passageway providing fluid communication from the tubing below the seating nipple to the tubing above the seating nipple, said main plug body having a downwardly-facing shoulder area around the exterior thereof adapted to seat against an upwardly-facing shoulder area of a seating nipple and form a fluid impermeable seal therewith; b. relief plug means carried by said main plug body and biased to close said passageway therein; c. a relief plug port extending through the relief plug means to provide fluid communication between the passageway and the upper portion of the relief plug means; d. connecting means attached to said relief plug means for connecting said apparatus to cable means for lowering and raising said apparatus through the well tubing string; e. said relief plug means being adapted to close said passageway when the apparatus is seated in a seating nipple and no upward force is imposed on said connecting means, and to open said passageway when an upward force is applied to said connecting means, and f. means forming a part of said apparatus for attaching a pressure indicating means to said apparatus.