Assembly And Method To Secure Tubing String to Blowout Preventer

Abstract

A flange assembly and method for securing the downhole tubing string and packer to a blowout preventer is disclosed. The application is particularly useful for high pressure fluid applications downhole such as hydraulic fracking.

1 . A flange assembly for securing a tubing string to a blowout preventer comprising:
 a threaded flange comprising:
 a main body having a lower surface for engagement with the upper flange of a blowout preventer, a plurality of bolt holes passing through the main body and arranged circumferentially and spaced for alignment with corresponding holes on a blowout preventer; 
 a neck portion integral with and extending outward from the main body; 
 a central aperture having a first inside diameter passing through the main body and a second inside diameter passing through said neck portion, said first inside diameter being larger than said second inside diameter; said neck portion further having a set of female threads; and, 
   a mandrel comprising:
 a first end and a second end, an aperture passing through the mandrel, a set of female threads at said first end for operatively connecting to a down hole tubing string and a set of female threads at said second end for operatively connecting to surface pumps, and a set of male threads located at said second end; said mandrel slidably receivable within the central aperture of the main body of said threaded flange where the female threads of said neck portion can threadably engage the male threads of said mandrel. 
   
     
     
         2 . The flange assembly of  claim 1  where said mandrel further comprises at least one annular groove. 
     
     
         3 . The flange assembly of  claim 2  where an O-ring is positioned within each respective at least one annular groove. 
     
     
         4 . The flange assembly of  claim 1  where said mandrel further comprises a pre-determined outside diameter from said first end to said second end and where the crest of said male threads is equivalent to said pre-determined outside diameter. 
     
     
         5 . In combination with a hydraulic fracturing operation for a well having a hydrocarbon bearing zone and casing string extending up to a surface casing flange, a blowout preventer connected to the casing flange and a tubing string and packer positioned at a pre-determined depth within the casing string for the delivery of fluid from surface pumps connected to the tubing string at high pressure, the method for securing the tubing string to the blowout preventer comprising the steps of:
 providing a threaded flange comprising:
 a main body having a lower surface for engagement with the upper flange of a blowout preventer, a plurality of holes passing through the main body and arranged circumferentially and spaced for alignment with corresponding holes on a blowout preventer; 
 a neck integral with and extending outward from the main body; 
 a central aperture having a first inside diameter passing through the main body and a second inside diameter passing through said neck, said first inside diameter being larger than said second inside diameter; said neck further having a set of female threads; and, 
 a mandrel comprising: 
 a first end and a second end, an aperture passing through the mandrel, a set of female threads at said first end for operatively connecting to a downhole tubing string and a set of female threads at said second end for operatively connecting to surface pumps, and a set of male threads located at said second end; said mandrel slidably receivable within the central aperture of the main body of said threaded flange where the female threads of said neck threadably engage the male threads of said mandrel; 
   operatively connecting the first end of said mandrel to the downhole tubing string;   positioning the threaded flange upon said mandrel where the lower surface of said main body is facing the blowout preventer;   setting the packer at the pre-determined depth ;   rotating the threaded flange to engage the male threads of said mandrel;   aligning said plurality of holes on the threaded flange to bolt holes on a blowout preventer;   securing said threaded flange to said blowout preventer; and, operatively connecting the second end of said mandrel to the surface pumps.