Wellbore pressure testing method and apparatus

Abstract

An apparatus for sensing the pressure of a well fluid in a subsurface wellbore in which a first, elongated tubing is adapted to extend from the surface of the earth to a subsurface location at which the pressure is to be measured, a fluid receiving chamber is disposed on the lower end of the first tubing, a second, elongated tubing, of smaller cross-section than the first, is disposed in the first tubing with its upper end at the surface of the earth and its lower end sealed within the lower end of the first tubing or the upper end of the fluid receiving chamber and is adapted to receive a pressure transmitting fluid and to be placed in fluid communication with the fluid receiving chamber and a pressure responsive closure element closes the lower end of the first tubing, the upper end of the fluid receiving chamber or the lower end of the fluid receiving chamber and is adapted to open at a pressure above the pressure of the well fluid and permit the pressure of the well fluid to be balanced against the pressure of the pressure transmitting fluid within the fluid receiving chamber. A method of sensing the fluid pressure at a subsurface location in a wellbore is also disclosed in which a pressure transmitted fluid is disposed in the second tubing, the pressure of the pressure transmitting fluid is increased to a pressure sufficient to open the closure, the pressure of the pressure transmitting fluid is balanced against the pressure of the well fluid in the fluid receiving chamber and the pressure of the pressure transmitting fluid is sensed at the surface of the earth.

Dependencies are inferred from the claim text.