Straddle tool with disconnect between seals

Abstract

A bottom hole assembly (BHA) enables a one trip procedure to set a bridge plug and release from that bridge plug with the BHA. A perforating gun is fired and a straddle tool above the gun in repositioned to wash the perforations as the opposed packer cups are moved along the perforations. At the end of the washing step a dropped ball closes a circulation port above the upper packer cups and the ball seat is blown out. A disconnect releases the lower part of the straddle tool with the lower packer cups that are uphole oriented. Cement can now be delivered past the upper packer cups and pressurized to squeeze the cement into the perforations using the upper cups to hold the pressure. Another ported sub above the upper cups has a port opened to prevent swabbing as the BHA is removed.

1 . A drill pipe string borne borehole assembly comprising a washing tool assembly, comprising:
 a main body having an axial main bore passage with one or more laterally directed perforation wash ports, provided with one or more lower swab cups below and one or more upper swab cups above said main body;   a lower ported sub having at least one port below said lower swab cups and a bypass passage to an upper ported sub with at least one port above said upper swab cups,   an actuated valve arranged for closing said one or more upper port; and   a disconnector for said main body including said main bore passage for forming a wide aperture at a remaining lower end of said disconnected main bore passage for pumping out cement.   
     
     
         2 . The borehole assembly according to  claim 1 , further comprising a perforation gun arranged below said washing tool assembly. 
     
     
         3 . The borehole assembly of  claim 2 , comprising below said perforation gun a plug actuator arranged for setting a bridge plug in said casing, and a second disconnector arranged between said perforation gun and said plug. 
     
     
         4 . The borehole assembly of  claim 3 , said second disconnector arranged between said perforation gun and said plug actuator. 
     
     
         5 . The borehole assembly of  claim 1 , wherein said aperture is larger than said washing port. 
     
     
         6 . The borehole assembly of  claim 1 , wherein said disconnector is ball or pressure operated. 
     
     
         7 . The borehole assembly of  claim 1 , wherein said upper and lower swab cups are opposed in facing mirror image. 
     
     
         8 . The borehole assembly of  claim 1 , wherein said disconnector is arranged for releasing a portion of said body that includes said wash port and said lower swab cups to expose said aperture end of said main bore. 
     
     
         9 . The borehole assembly of  claim 8 , wherein said lower swab cups sealingly engage the casing after said disconnector has released to retain pressure against fluid delivered through said exposed aperture of said passage. 
     
     
         10 . The borehole assembly of  claim 1 , wherein said upper swab cups continue to engage the casing after said disconnector has released to retain pressure against fluid delivered through said exposed aperture of said passage. 
     
     
         11 . A method for plugging a cased petroleum well comprising the steps of:
 a) assembling on a drill pipe string a borehole assembly comprising a bridge plug on a plug setting tool arranged below perforation guns further arranged below a wash tool assembly with a main bore and with upper swab cups and lower swab cups which are bypass ported by upper ports via a passage to lower ports, and an intermediate ported body with wash ports arranged for washing through perforated casing;   b) running in said BHA until said bridge plug and said perforation guns are sufficiently below a zone in the casing to be perforated, perforated;   c) setting and releasing said bridge plug;   d) positioning and firing said perforating guns perforating said zone of said casing;   e) positioning said wash tool assembly and washing behind said now perforated casing, and circulating out washed-out debris;   f) closing upper ports in upper bypass port;   g) using a disconnector arranged below said upper swab cups and said upper ports, of said wash tool assembly, thereby disconnecting and releasing a lower half of said wash tool assembly with said perforating guns, so forming a main bore aperture at or below an upper half of said disconnector, and letting them drop; and   h) pumping down cement via said main bore aperture, cementing from a lower portion of said perforated range and continuing upwardly until said perforated range is cemented.   
     
     
         12 . The method of  claim 11 , controlling one or more of said operations using pumped ball and seat release mechanisms and releasing said seats using pressure on shear pins of said seats. 
     
     
         13 . The method of  claim 12 , drilling through said cemented interval of said perforated casing and running a test log to verify the cementing, and cementing it. 
     
     
         14 . The borehole assembly of  claim 2 , wherein said aperture is larger than said washing port. 
     
     
         15 . The borehole assembly of  claim 3 , wherein said aperture is larger than said washing port. 
     
     
         16 . The borehole assembly of  claim 4 , wherein said aperture is larger than said washing port. 
     
     
         17 . The borehole assembly of  claim 2 , wherein said disconnector is ball or pressure operated. 
     
     
         18 . The borehole assembly of  claim 3 , wherein said disconnector is ball or pressure operated. 
     
     
         19 . The borehole assembly of  claim 4 , wherein said disconnector is ball or pressure operated. 
     
     
         20 . The borehole assembly of  claim 5 , wherein said disconnector is ball or pressure operated.