System and method for subterranean access

Abstract

A system for accessing a subterranean zone from the surface includes a first, second and third entry well bore extending from the surface, the first, second and third entry well bores located on the same drilling pad at the surface. A slanted well bore extends from each of the entry well bores to the subterranean zone. A substantially horizontal drainage pattern extends from the slanted well bores into the subterranean zone.

What is claimed is:  
     
         1 . A method for accessing a subterranean zone from the surface, comprising: 
 forming a first entry well bore from the surface;    forming one or more slanted well bores from the first entry well bore to the subterranean zone;    forming a second entry well bore from the surface, the second entry well bore located on the same drilling pad as the first entry well bore at the surface;    forming one or more slanted well bores from the second entry well bore to the subterranean zone;    forming a third entry well bore from the surface, the third entry well bore located on the same drilling pad as the first and second entry well bores at the surface;    forming one or more slanted well bores from the third entry well bore to the subterranean zone; and    forming a substantially horizontal drainage pattern from each of the slanted well bores into the subterranean zone.    
     
     
         2 . The method of  claim 1 , wherein the horizontal drainage patterns comprise a horizontal well bore extending from the slanted well bore and a plurality of lateral well bores extending from the horizontal well bore.  
     
     
         3 . The method of  claim 2 , wherein the horizontal drainage patterns comprise a crow's foot configuration.  
     
     
         4 . The method of  claim 2 , wherein the lateral well bores are configured to drain an area of the subterranean zone of at least 640 acres.  
     
     
         5 . The method of  claim 2 , wherein the horizontal drainage patterns comprise a pinnate configuration.  
     
     
         6 . The method of  claim 1 , further comprising removing resources from the subterranean zone through the horizontal drainage patterns to the surface.  
     
     
         7 . The method of  claim 1 , further comprising forming an enlarged cavity in each of the slanted well bores proximate to and above the subterranean zone.  
     
     
         8 . The method of  claim 1 , further comprising forming an enlarged cavity in each of the slanted well bores above the horizontal drainage pattern.  
     
     
         9 . The method of  claim 7 , wherein the enlarged cavity is located proximate to the junction of the slanted well bore and the substantially horizontal drainage pattern.  
     
     
         10 . The method of  claim 1 , wherein the first, second, and third entry well bores are spaced approximately twenty feet apart.  
     
     
         11 . The method of  claim 1 , further comprising forming a second horizontal drainage pattern from each of the slanted well bores into a second subterranean zone.  
     
     
         12 . A system for accessing a subterranean zone from the surface, comprising: 
 a first entry well bore extending from the surface;    a second entry well bore extending from the surface, the second entry well bore located on the same drilling pad as the first entry well bore at the surface;    a third entry well bore extending from the surface, the third entry well bore located on the same drilling pad as the first and second entry well bores;    one or more slanted well bores extending from each of the first, second, and third entry well bores to the subterranean zone; and    a substantially horizontal drainage pattern extending from the slanted well bores into the subterranean zone.    
     
     
         13 . The system of  claim 12 , wherein the horizontal drainage patterns comprise a horizontal well bore extending from the slanted well bore and a plurality of lateral well bores extending from the horizontal well bore.  
     
     
         14 . The system of  claim 13 , wherein the horizontal drainage patterns comprise a crow's foot configuration.  
     
     
         15 . The system of  claim 13 , wherein the lateral well bores are configured to drain an area of the subterranean zone of at least 640 acres.  
     
     
         16 . The system of  claim 13 , wherein the horizontal drainage patterns comprise a pinnate configuration.  
     
     
         17 . The system of  claim 12 , further comprising an enlarged cavity in each of the slanted well bores proximate to the subterranean zone.  
     
     
         18 . The system of  claim 12 , further comprising an enlarged cavity in each of the slanted well bores between the surface and the horizontal drainage pattern.  
     
     
         19 . The system of  claim 17 , wherein the enlarged cavity is located proximate to the junction of the slanted well bore and the substantially horizontal drainage pattern.  
     
     
         20 . The system of  claim 12 , wherein the first, second, and third entry well bores are spaced approximately twenty feet apart at the surface.  
     
     
         21 . The system of  claim 12 , further comprising a second substantially horizontal drainage pattern extending from each slanted well bore into a second subterranean zone.  
     
     
         22 . A system for accessing a subterranean zone from the surface, comprising: 
 three or more entry well bores extending from the surface;    one or more slanted well bores extending from each entry well bore to the subterranean zone;    a substantially horizontal drainage pattern extending from the slanted well bores into the subterranean zone; and    an enlarged cavity in each of the one or more slanted well bores, located proximate to the junction of the slanted well bore and the substantially horizontal drainage pattern.    
     
     
         23 . A system for accessing multiple subterranean zones from the surface, comprising: 
 three ore more entry well bores extending from the surface;    one or more slanted well bores extending from each entry well bore to one or more subterranean zones;    one or more substantially horizontal drainage patterns extending from the slanted well bores into each of the one or more subterranean zones; and    one or more enlarged cavities in each of the slanted well bores positioned proximate to the junction of the slanted well bores and the one or more of the substantially horizontal drainage patterns.    
     
     
         24 . The system of  claim 23 , wherein the three or more entry well bores are located on the same drilling pad.