Well completion clean-up fluids and method for cleaning-up drilling and completion filtercakes

Abstract

The present invention relates to a new aqueous wash composition suitable for the clean-up of drilling and completion fluid filtercakes. The wash composition comprises water and an effective amount of cationic salts of polyaminocarboxylic acids at neutral or acidic pH. The wash composition is preferably used for wellbore completion process.

1 . An aqueous wash composition suitable for the clean-up of drilling and completion fluid filtercakes comprising water and an effective amount of cationic salts of polyaminocarboxylic acids at neutral or acidic pH.  
     
     
         2 . The aqueous wash composition according to    claim 1    further comprising an enzyme or oxidiser.  
     
     
         3 . The aqueous wash composition of    claim 1    wherein the polyaminocarboxylic acid is a di-cation salt of (ethylenedinitrilo) tetraacetic acid.  
     
     
         4 . The aqueous wash composition according to    claim 2    wherein the cation is potassium.  
     
     
         5 . The aqueous wash composition according to    claim 3    wherein the cation is potassium.  
     
     
         6 . The aqueous wash composition of    claim 4    wherein the pH is between 3.5 and 8.0.  
     
     
         7 . The aqueous wash composition according to    claim 3    wherein the pH is between 4.7 and 5.5.  
     
     
         8 . The aqueous wash composition according to    claim 4    wherein the pH is between 4.7 and 5.5.  
     
     
         9 . The aqueous wash composition of    claim 3    in a gelled form.  
     
     
         10 . The aqueous wash composition of    claim 4    in a gelled form.  
     
     
         11 . A wellbore completion process comprising drilling the well with a drilling fluid and then cleaning-up a filtercake, using an aqueous wash composition of    claim 1   .  
     
     
         12 . A wellbore completion process comprising drilling a well using drilling fluid followed by removal of a filtercake, using an aqueous wash composition of    claim 2   .  
     
     
         13 . A wellbore completion process comprising drilling a well using drilling fluid followed by removal of a filtercake, using an aqueous wash composition of    claim 3   .  
     
     
         14 . A wellbore completion process comprising drilling a well using drilling fluid followed by removal of a filtercake, using an aqueous wash composition of    claim 4   .  
     
     
         15 . A wellbore completion process comprising drilling a well using drilling fluid followed by removal of a filtercake, using an aqueous wash composition of    claim 5   .  
     
     
         16 . A wellbore completion process comprising drilling a well using drilling fluid followed by removal of a filtercake, using an aqueous wash composition of    claim 6   .  
     
     
         17 . A method of cleaning a wellbore filtercake comprising applying the wash composition according to    claim 1    with an overbalance in pressure from the wellbore to the formation.  
     
     
         18 . A method for cleaning a wellbore filtercake comprising applying the wash composition of    claim 1    under overbalanced conditions.  
     
     
         19 . A method for cleaning a wellbore filtercake comprising applying the wash composition of    claim 3    under overbalanced conditions.  
     
     
         20 . A method for cleaning a wellbore filtercake comprising applying the wash composition of    claim 5    under overbalanced conditions.