Continuous flow perforation washing tool and method

A continuous flow perforation washing tool for use in a well bore comprising:

• a tubular mandrel having exterior sidewalls and an interior flow passage, an upper end adapted to be connected in a pipe string extending to the well surface, and a lower end with means adapted to block the flow of fluids from said pipe string through said mandrel flow passage;
• upper and lower packer assemblies carried on said mandrel at opposite ends thereof, each of said packer assemblies including a solid, compressible elastomeric seal ring;
• an outer setting sleeve surrounding said mandrel between said packer assemblies defining an annular chamber between said mandrel and said setting sleeve, said annular chamber being in continuous fluid communication with said mandrel flow passage through port means provided in the sidewalls of said mandrel and with said well bore through orifice means provided in said setting sleeve, prior to and after setting said packer assemblies;
• said outer setting sleeve being connected to a first seal body at one end thereof which is slidably received on said mandrel exterior, said seal body having an outer recess for receiving one of said elastomeric seal rings;
• and
• a second seal body having an annular seal portion slidably received between said mandrel exterior and the end of said setting sleeve opposite said first seal body, said second seal body having an outer recess for receiving said other of said elastomeric seal rings, each of said recesses including a face region abutting an end of its associated seal ring and a sleeve portion which contacts the interior of its associated seal ring whereby sliding movement of said setting sleeves compresses said seal rings to set said packer assemblies.

A continuous flow perforation washing tool for use in a well bore comprising:

• a tubular mandrel having exterior sidewalls and an interior flow passage, an upper end adapted to be connected in a pipe string extending to the well surface, and a lower end with a ball catching sub adapted to catch a ball dropped from the surface to thereby block the flow of fluids from said pipe string through said mandrel flow passage;
• upper and lower packer assemblies carried on said mandrel at opposite ends thereof, each of said packer assemblies including a solid, compressible elastomeric seal ring;
• an outer setting sleeve surrounding said mandrel between said packer assemblies defining an annular chamber between said mandrel and said setting sleeve, said annular chamber being in continuous fluid communication with said mandrel flow passage through port means provided in the sidewalls of said mandrel and with said well bore through orifice means provided in said setting sleeve, prior to and after setting said packer assemblies;
• said outer setting sleeve being connected to a first seal body at one end thereof which is slidably received on said mandrel exterior, said seal body having an outer recess for receiving one of said elastomeric seal rings;
• a second seal body having an annular seal portion slidably received between said mandrel exterior and the end of said setting sleeve opposite said first seal body, said second seal body having an outer recess for receiving said other of said elastomeric seal rings, each of said recesses including a face region abutting an end of its associated seal ring and a sleeve portion which contacts the interior of its associated seal ring whereby sliding movement of said setting sleeves compresses said seal rings to set said packer assemblies;
• and
• said orifice means being selectively sized to provide controlled flow to said well bore whereby fluid pressure communicated by said port means in said mandrel to said annular chamber acts on said first and second seal bodies to seal said elastomeric seal rings in said well bore.

A method for circulating fluid in a well having a perforated casing, comprising the steps of:

• attaching a wash tool to the lower end of a pipe string, the wash tool having an inner mandrel with a flow passage therethrough communicating with said pipe string, pressure responsive, solid compressible packer assemblies at opposite ends thereof, a setting sleeve surrounding the mandrel between the packer assemblies to define an annular chamber between the mandrel and setting sleeve, port means communicating the mandrel interior with the annular chamber, and selectively sized orifices in said setting sleeve communicating the annular chamber with the well bore prior to and after setting said packer assemblies;
• lowering the wash tool on the pipe string to the desired circulation level within said perforated casing;
• actuating closure means to close the lower end of said mandrel flow passage;
• pumping fluid through said pipe string to said closed mandrel flow passage, through said port means in said mandrel to said annular chamber, and continuously through said sized orifices in said setting sleeve to said well bore, the number and size of said orifices being selected to provide a controlled flow of fluid through said orifices to create a back pressure in said annular chamber and thereby hydraulically actuate said packer assemblies;
• and
• continuing to circulate fluid through said pipe string, mandrel, annular chamber and orifices, through perforations in said casing between said packer assemblies, through the zone surrounding said casing, through perforations in said casing above said packer assemblies and back to the surface of said well through the annulus between said pipe string and said casing.