Combination burst-disc subassembly for horizontal and vertical well completions

Abstract

A combination profile and burst-disc subassembly is provided for use in directional, horizontal or deviated or vertical wells during snubbing, bridge plug retrieval or zone separation operations in combination with packers and/or completion strings; the sub provides an plug for non-vertical situations which can be opened without wireline, while providing a landing for a wireline plug which may be required for vertical well sections during related operations.

What is claimed is: 
     
         1 . A subassembly with at least two pressure sealing mechanisms, comprising (i) a burst disc and (ii) a fitting for a profile plug  6 . 
     
     
         2 . A method of sealing a tubing string during injection into a wellbore by providing a subassembly within the tubing string sealed by an intact burst disc. 
     
     
         3 . The method of  claim 2  where the tubing string is also sealed with a plug seated and sealed into a plug receiving profile fitting. 
     
     
         4 . A method of unsealing a tubing string after installation into a wellbore comprising bursting a burst disc within a combination burst disc-profile fitting subassembly in line in the string by injection of fluid under pressure higher than the burst pressure of the burst disc, and then resealing the tubing string for removal or other operational reasons by landing and seating and sealing a profile plug into the included profile fitting in the subassembly attached to the tubing. 
     
     
         5 . A subassembly for horizontal and vertical wellbore completions with at least two pressure sealing mechanisms, the pressure sealing mechanisms being (i) a single-use burst disc for sealing and (ii) a profile fitting for a mating profile plug provided to the subassembly from surface for insertion into the mating profile fitting of the subassembly to latch, seat and form a seal when required for sealing. 
     
     
         6 . A method for unsealing a tubing string after installation into a wellbore the tubing string having first been sealed at surface with an intact burst disc within a combination burst disc-profile fitting subassembly where an included profile fitting is uphole of the burse disc, comprising bursting the burst disc by injection of fluid under pressure higher than the burst pressure of the burst disc on its surface side, and then resealing the tubing string for removal or other operational reasons by landing and seating and latching a profile plug supplied from surface into the included mating profile fitting in the subassembly attached to the tubing in order to form a seal to reseal the tubing. 
     
     
         7 . The method of  claim 6  where the tubing string is first sealed with an intact burst disc and is also sealed with a plug seated and latched and sealed into the included profile fitting.