Use of an Additive Compostion for Cementing Bore Wells

Abstract

The present invention relates to the use of a composition for reinforcing cement, which comprises one or more compounds selected from group: a) sodium chloride, potassium chloride, magnesium chloride, calcium chloride, strontium chloride, barium chloride and ammonium chloride; b) aluminum chloride; and comprises one or more compounds selected from c) silica, zeolite, and apatite for cementing a wellbore. Moreover, the present invention relates to a cement slurry for cementing a wellbore, comprising I): cement; II) water; and III) a composition for reinforcing cement. In addition, the present invention relates to a method of cementing a wellbore.

1 . Use of a composition for reinforcing cement, which comprises:
 one or more compounds selected from group: a) sodium chloride, potassium chloride, magnesium chloride, calcium chloride, strontium chloride, barium chloride and ammonium chloride; b) aluminum chloride; and comprises one or more compounds selected from c) silica, zeolite, and apatite for cementing a wellbore.   
     
     
         2 . Use of a composition according to  claim 1 , in which composition the compounds from group a) contains at least sodium chloride and calcium chloride. 
     
     
         3 . Use of a composition according to  claim 1 , said composition comprising 45 to 90% by weight of group; a) 1 to 10% by weight of group b) and 1 to 10% by weight of the components from group c), based on the total weight of groups a+b+c. 
     
     
         4 . Use of a composition according to  claim 1 , which composition also contains magnesium oxide and/or calcium oxide. 
     
     
         5 . Use of a composition according to  claim 1 , said composition containing sodium chloride, potassium chloride, magnesium chloride, calcium chloride, ammonium chloride, aluminium chloride, magnesium oxide and silica and/or zeolite. 
     
     
         6 . Use of a composition according to  claim 1 , wherein group c) consists of silica. 
     
     
         7 . Use of a composition according to  claim 1 , which composition comprises magnesium hydrogen phosphate, magnesium sulphate and/or sodium carbonate. 
     
     
         8 . Cement slurry for cementing a wellbore, said cement slurry comprising:
 I) cement; II) water; and III) a composition for reinforcing cement, which comprises one or more compounds selected from group: a) sodium chloride, potassium chloride, magnesium chloride, calcium chloride, strontium chloride, barium chloride and ammonium chloride; b) aluminum chloride; and comprises one or more compounds selected from; c) silica, zeolite, and apatite.   
     
     
         9 . Cement slurry for cementing a wellbore according to  claim 8 , comprising between 50 and 85 wt %, preferably between 65 and 75 wt % of I) cement, and between 20 and 40 wt %, preferably between 25 and 30 wt % of II) water, and between 0.1 and 10 wt %, preferably between 1 and 3 wt %, more preferably between 1.5 and 2.5 wt % of composition III). 
     
     
         10 . A method of cementing a wellbore, comprising the steps of: i) drilling a wellbore; ii) introducing a casing string into the wellbore; iii) preparing a cement slurry based on a combination of cement and the composition for reinforcing cement, which comprises one or more compounds selected from group: a) sodium chloride, potassium chloride, magnesium chloride, calcium chloride, strontium chloride, barium chloride and ammonium chloride; b) aluminum chloride; and comprises one or more compounds selected from c) silica, zeolite and apatite; iv) pumping said cement slurry into the wellbore; and v) allowing said cement slurry to set.