Deviated drilling method for water production

Abstract

Method for drilling horizontal or deviated water wells through hard and fragmented rock formations that are prone to caving, such as Hawaiian basalts. The method may be used to drill into basal aquifers directly underlain by salt water, compartmented aquifers, and perched aquifers. The method uses deviated drilling and may use formation pre-grouting, casing drilling, and/or percussion drilling, and a percussion drilling tool may be combined with a casing drill string.

1 . A method for drilling a deviated water well in a subsurface formation having interbedded hard and fragmented rocks and that is prone to caving, said formation having a subterranean aquifer below a water table, comprising the steps of: 
 drilling a first section of a well in a direction from the earth's surface, the direction selected from downward, laterally, and combinations thereof;    causing the drilling direction to deviate from the direction of said first section in a predetermined path to intersect the aquifer; and    continuing to drill in a path extending into the aquifer at a predetermined depth below the water table.    
   
   
       2 . The method of  claim 1 , wherein at least one of said causing step and said continuing step comprises using a casing drilling method.  
   
   
       3 . The method of  claim 1 , wherein at least one of said causing step and said continuing step comprises using a drilling tool selected from rotary bits and percussion tools.  
   
   
       4 . The method of  claim 1 , wherein at least one of said causing step and said continuing step comprises using a percussion tool that is combinable with casing used in a casing drilling method.  
   
   
       5 . The method of  claim 1 , further comprising the step of pre-grouting a portion of the formation by injecting cementitious material prior to drilling through said portion.  
   
   
       6 . The method of  claim 1 , wherein the aquifer is a basal aquifer directly underlain by salt water and occurring within and across dipping strata, and said path extends into the aquifer substantially horizontally and is oriented substantially parallel to the strike of the strata.  
   
   
       7 . The method of  claim 1 , wherein said aquifer is a basal aquifer directly underlain by salt water and occurring within rocks comprising basalt lava, pyroclastics, coral, sediments, or combinations thereof.  
   
   
       8 . The method of  claim 1 , wherein the aquifer is a basal aquifer directly underlain by salt water, and said continuing step comprises drilling in a substantially horizontal path near the top of said aquifer.  
   
   
       9 . The method of  claim 1 , wherein the aquifer is selected from a dike-compartmented aquifers and perched aquifers.  
   
   
       10 . (canceled)  
   
   
       11 . The method of  claim 1 , further comprising the step of using said well for a purpose selected from water production, subsurface exploration, geothermal energy production, and pressure control.  
   
   
       12 . The method of  claim 1 , further comprising the step of drilling a second section between said first section and said path, said portion being lower than said path and forming a J-shaped trap into which a pump can be positioned vertically.  
   
   
       13 . The method of  claim 1 , wherein said formation comprises volcanic rocks.  
   
   
       14 . The method of  claim 1 , wherein said formation comprises interbeds of rocks selected from lava flows, clinker, and pyroclastics.  
   
   
       15 . A deviated water well, comprising: 
 a first section extending downward from the surface; and    a second section extending in a different direction into an aquifer below a water table in a subsurface formation, wherein the formation includes interbedded hard and fragmented rocks and is prone to caving.    
   
   
       16 . The well of  claim 15 , further comprising a J-shaped section between said first and second sections.  
   
   
       17 . The well of  claim 15 , wherein the subsurface formation comprises rocks selected from basalt lava, pyroclastics, coral, sediments, and combinations thereof.  
   
   
       18 . The well of  claim 15 , wherein said aquifer is selected from basal aquifers underlain by brackish or salt water, dike-compartmented aquifers, and perched aquifers.  
   
   
       19 . The well of  claim 15 , wherein said subsurface formation comprises dipping beds and said substantially horizontal section is oriented substantially parallel to the strike of the beds.  
   
   
       20 . The well of  claim 15 , further comprising a plurality of additional sections extending in different directions into the aquifer.  
   
   
       21 . The well of  claim 15 , further comprising a plurality of additional sections extending in different directions into a plurality of aquifers.