Method for drilling multilateral wells and related device

Abstract

An improved method for drilling a lateral well from an existing wellbore is disclosed whereby a section of said existing wellbore is preferably enlarged such as by under-reaming. The enlarged section is filled with a material such as, for example, epoxy which hardens to form an impermeable body. The hardened material is drilled out laterally and also longitudinally, such that a sealed junction is formed within the impermeable body between the lateral well and existing well. In one embodiment of the present invention, a packer positioned within the enlarged may be filled with the material to thereby avoid any contamination of the material with other downhole elements such as mud and oil whereby the composition of the material is consistent and known. In one embodiment, a drillable guide may be positioned in the enlarged section prior to filling the enlarged section with material to thereby subsequently guide a drill bit through the hardened material for reestablishing a path within the existing wellbore.

What is claimed is:  
     
         1 . A method of forming a junction between a first wellbore and one or more lateral wells which branch from said first wellbore, said method comprising: 
 enlarging a portion of said first wellbore to form an enlarged section of said first wellbore;    pumping material into said enlarged section, said material hardening within said enlarged section to form hardened material; and    forming said one or more lateral wells by drilling out a lateral path through said hardened material whereby said junction of said first wellbore and said one or more lateral wells is formed within said hardened material.    
     
     
         2 . The method of  claim 1  wherein said step of enlarging is made before initiating drilling of said one or more lateral wells.  
     
     
         3 . The method of  claim 1 , further comprising: 
 running a drillable guide into said first wellbore before said step of pumping.    
     
     
         4 . The method of  claim 3 , further comprising: 
 reestablishing said first wellbore by utilizing said drillable guide for guiding drilling.    
     
     
         5 . The method of  claim 1 , further comprising: 
 reestablishing said first wellbore by drilling out a primary well path through said hardened material within said enlarged section.    
     
     
         6 . The method of  claim 5 , further comprising: 
 positioning a deflection assembly within said primary well path.    
     
     
         7 . The method of  claim 6 , further comprising: 
 mounting a whipstock to a sleeve within said primary well path.    
     
     
         8 . The method of  claim 1 , further comprising: 
 positioning a packer within said enlarged section.    
     
     
         9 . The method of  claim 8 , further comprising: 
 inflating said packer during said step of pumping by pumping said material into said packer.    
     
     
         10 . The method of  claim 3 , further comprising: 
 positioning a packer around said drillable guide.    
     
     
         11 . The method of  claim 1  wherein said material comprises an epoxy.  
     
     
         12 . A method for drilling a second wellbore that branches laterally from a first wellbore, the method comprising the steps of: 
 filling a section of said first wellbore with a fluid material which hardens to form a solid material; and    initiating drilling of said second wellbore from said section of said first wellbore to thereby form a junction of said first wellbore and said second wellbore.    
     
     
         13 . The method of  claim 12 , wherein said cement comprises an epoxy material.  
     
     
         14 . The method of  claim 12 , further comprising: 
 installing a drillable guide within said section prior to said step of filling.    
     
     
         15 . The method of  claim 12 , wherein said step of filling further comprises plugging said first wellbore with an inflatable packer by pumping said fluid material into said packer.  
     
     
         16 . The method of  claim 12 , further comprising: 
 under-reaming said section prior to said step of filling.    
     
     
         17 . A downhole connection arrangement between a first wellbore and a second wellbore branching from said first wellbore, said connection arrangement comprising: 
 an impermeable body formed of hardened material which has hardened from a fluid state, said body being positioned along said first wellbore, said impermeable body defining therein a first passageway, said first passageway being an extension said first wellbore to interconnect said first wellbore above and below said impermeable body, said impermeable body defining therein a second passageway, said second passageway being an extension of said second wellbore, said first passageway and said second passageway interconnecting within said impermeable body.    
     
     
         18 . The connection arrangement of  claim 17 , wherein said body is positioned within an enlarged portion of said first wellbore.  
     
     
         19 . The connection arrangement of  claim 17 , further comprising: 
 an inflatable packer, said body being positioned within said inflatable packer.    
     
     
         20 . The connection arrangement of  claim 17 , further comprising: 
 a sleeve mounted within said body.    
     
     
         21 . The connection arrangement of  claim 17 , wherein said body is substantially cylindrical.  
     
     
         22 . A method for drilling a second wellbore that branches laterally from a first wellbore, the method comprising the steps of: 
 opening a section of said first wellbore    pumping a fluid material into said section of said first wellbore whereupon said fluid material hardens to form a solid material;    mounting a deflection assembly within solid material; and    drilling said second wellbore through said solid material to thereby form a junction of said first wellbore and said second wellbore within said solid material.    
     
     
         23 . The method of  claim 22 , wherein said cement comprises an epoxy material.  
     
     
         24 . The method of  claim 22 , further comprising: 
 installing a drillable guide within said section prior to said step of pumping.    
     
     
         25 . The method of  claim 22 , wherein said step of pumping further comprises inflating an inflatable packer by pumping said fluid material into said packer.