Multizone Stimulation Using Wax Balls

Abstract

A diverter for use in multizone stimulation processes and characterised in that it comprises a ball consisting of wax with an appropriate melting point, size and specific gravity for use in the stimulation process.

1 - 6 . (canceled)  
   
   
       7 . A diverter for use in multizone stimulation processes, the diverter comprising a ball being comprised essentially of wax having an appropriate melting point and a specific gravity for use in the stimulation process, the wax ball being sized such that it is forced into a perforation in a wall of a well by the application of pressure and hence forms a seal.  
   
   
       8 . The diverter according to  claim 7 , comprising wax and an appropriate diluent, wherein the diluent is used to adjust the specific gravity of the ball such that it is at least similar to the specific gravity of the chemical fluids to be used in the stimulation process.  
   
   
       9 . The diverter according to  claim 7 , wherein the diverter is spherical.  
   
   
       10 . The diverter according to  claim 9 , wherein the diameter of the spheres are in the range 16 mm to 22 mm.  
   
   
       11 . A method of producing a diverter suitable for use in multizone stimulation processes, wherein, 
 a) the process used to produce the diverters is an injection moulding process;    b) the material used in the process is comprised essentially of wax with or without a diluent and having a melting point and specific gravity appropriate to the intended use; and    c) the mould cavities defining the shape of the moulded products are ball-shaped and sized to form a ball which fits into a perforation in a wall of a well, by the application of pressure, and hence forms a seal.    
   
   
       12 . A multizone stimulation process comprising the steps of: 
 a) chemically treating an area to improve the flow of oil or gas through rock strata;    b) sealing the chemically treated area by insertion under pressure of diverters into perforations in the wall of a well; and    c) subsequently releasing the diverters to allow oil to flow;    wherein the use of diverters which comprises essentially of wax (with or without a diluent) balls of an appropriate size, specific gravity and melting point that, on release of the sealing pressure, they melt as they are carried upwards in the oil flow, the wax balls being sized such that they enter into the perforations in the wall of the well by the application of pressure, and hence seal the perforations.