Method of cementing an off bottom liner

Abstract

A method of cementing an off bottom liner including the steps of establishing a first flow blockage in the liner at a location down-hole of a cementing valve located in the side wall of the liner, opening the cementing valve which exposes openings in the sidewall of the liner, pumping cement down the liner and out through the openings in the sidewall of the liner, establishing a second flow blockage up-hole of the cementing valve, closing the cementing valve, opening the second flow blockage to establish fluid communication through the second flow blockage, and opening the first flow blockage to establish fluid communication through the first flow blockage. The steps of opening the first and second flow blockages are achieved by increasing the pressure in the liner above the blockages. In this way, it is possible to cement an off bottom liner and regain fluid communication to the wellbore below the liner without the need for any drilling operations.

1 . A method of cementing an off bottom liner comprising the steps of:
 establishing a first flow blockage in the liner at a location down-hole of a cementing valve located in the side wall of the liner;   opening the cementing valve to expose openings in the sidewall of the liner;   pumping cement down the liner and out through the openings in the sidewall of the liner;   establishing a second flow blockage up-hole of the openings in the cementing valve;   closing the cementing valve;   opening the second flow blockage to establish fluid communication through the second flow blockage; and   opening the first flow blockage to establish fluid communication through the first flow blockage;   wherein the steps of opening the first and second flow blockages are achieved by increasing the pressure in the liner above the blockages.   
   
   
       2 . A method according to  claim 1 , wherein the step of establishing a blockage at a location down hole of a cementing valve comprises the steps of pumping a wiper plug down the liner until it engages a collar located down hole of the cementing valve. 
   
   
       3 . A method according to  claim 1 , wherein the step of establishing a blockage at a location up hole of the openings in a cementing valve comprises the steps of pumping a wiper plug down the liner until it engages a collar located up hole of the openings in the cementing valve. 
   
   
       4 . A method according to  claim 2 , wherein the step of establishing a blockage at a location up hole of the openings in a cementing valve comprises the steps of pumping a wiper plug down the liner until it engages a collar located up hole of the openings in the cementing valve. 
   
   
       5 . A method according to  claim 1  wherein the method further comprises the step of establishing a seal below the cementing valve in order to separate the volume in the wellbore below the seal and the volume in the wellbore above the seal. 
   
   
       6 . A method according to  claim 2  wherein the method further comprises the step of establishing a seal below the cementing valve in order to separate the volume in the wellbore below the seal and the volume in the wellbore above the seal. 
   
   
       7 . A method according to  claim 3  wherein the method further comprises the step of establishing a seal below the cementing valve in order to separate the volume in the wellbore below the seal and the volume in the wellbore above the seal. 
   
   
       8 . A method according to  claim 4  wherein the method further comprises the step of establishing a seal below the cementing valve in order to separate the volume in the wellbore below the seal and the volume in the wellbore above the seal. 
   
   
       9 . A method according to  claim 1 , wherein the method further comprises the step of disabling a one-way valve located at the bottom of the liner. 
   
   
       10 . A method according to  claim 2 , wherein the method further comprises the step of disabling a one-way valve located at the bottom of the liner. 
   
   
       11 . A method according to  claim 3 , wherein the method further comprises the step of disabling a one-way valve located at the bottom of the liner. 
   
   
       12 . A method according to  claim 4 , wherein the method further comprises the step of disabling a one-way valve located at the bottom of the liner. 
   
   
       13 . A method according to  claim 5 , wherein the method further comprises the step of disabling a one-way valve located at the bottom of the liner. 
   
   
       14 . A method according to  claim 6 , wherein the method further comprises the step of disabling a one-way valve located at the bottom of the liner. 
   
   
       15 . A method according to  claim 7 , wherein the method further comprises the step of disabling a one-way valve located at the bottom of the liner. 
   
   
       16 . A method according to  claim 8 , wherein the method further comprises the step of disabling a one-way valve located at the bottom of the liner. 
   
   
       17 . A wiper plug comprising an outer wiper part and an inner hollow sleeve, and where the inner hollow sleeve is slideably arranged within the outer wiper part and is held in place by a release mechanism, wherein the inner hollow sleeve is formed with through going openings which are exposed when the release mechanism releases and the inner hollow sleeve extends out the end of the wiper part. 
   
   
       18 . A wiper plug according to  claim 17 , wherein the wiper plug further comprises a restraining mechanism which locks the inner hollow sleeve once it is extended into its extended position. 
   
   
       19 . A wiper plug according to  claim 17 , wherein the wiper plug further comprises a ratchet mechanism between the inner hollow sleeve and the outer part. 
   
   
       20 . A wiper plug according to  claim 18 , wherein the wiper plug further comprises a ratchet mechanism between the inner hollow sleeve and the outer part. 
   
   
       21 . An assembly comprising a liner, a liner hanger running tool, a top wiper plug suspended at the end of the liner hanger running tool, a sidewall cementing valve, a top collar arranged up hole of the openings in the cementing valve, a bottom plug arranged below the cementing valve, and where the top collar is arranged such that the top wiper plug engages the top collar when the top wiper plug is pumped down the liner, wherein the top wiper plug and the bottom plug are of the type which can be opened by applying pressure up hole of the plug. 
   
   
       22 . An assembly comprising a liner, a liner hanger running tool, a top wiper plug suspended at the end of the liner hanger running tool, a bottom wiper plug suspended below the top wiper plug, a sidewall cementing valve, a top collar arranged up hole of the openings in the cementing valve, a bottom collar arranged below the cementing valve, and where the top collar is arranged such that the top wiper plug sealingly engages the top collar when the top wiper plug is pumped down the liner and lets the bottom wiper plug pass the top collar when the bottom wiper plug is pumped down the liner and where the bottom collar is arranged to sealingly engage the bottom wiper plug when the bottom wiper plug is pumped down the liner. 
   
   
       23 . An assembly according to  claim 22 , wherein the inner diameter of the top collar is larger than the outer diameter of the bottom wiper plug and where the inner diameter of the bottom collar is less than the outer diameter of the bottom wiper plug and where the inner diameter of the top collar is smaller than the outer diameter of the top wiper plug. 
   
   
       24 . An assembly according to  claim 22 , wherein the top and bottom wiper plugs are of the kind which can be opened by increasing the pressure upstream of the wiper plug. 
   
   
       25 . An assembly according to  claim 23 , wherein the top and bottom wiper plugs are of the kind which can be opened by increasing the pressure upstream of the wiper plug.