Microwave process for intrinsic permeability enhancement and Hydrocarbon extraction from subsurface deposits

Abstract

Hydrocarbons are extracted from a target formation, such as oil shale, tar sands, heavy oil and petroleum reservoirs, by apparatus and methods which cause fracturing of the containment rock and liquification or volatization of the hydrocarbons by microwave energy directed by a radiating antenna in the target formation.

1 . A method of in-situ extraction of hydrocarbons from a selected layer of subsurface oil shale comprising the steps of drilling a hole down to the selected layer of oil shale and applying sufficient microwave energy to a directional antenna positioned in the selected layer to reduce the viscosity of the hydrocarbons to permit it to flow to the drilled hole. 
   
   
       2 . The method in accordance with  claim 1  comprising the further step of vaporizing a portion of the hydrocarbons and creating a sufficient pressure differential between the area where the hydrocarbons are vaporized and the drilled well to push the hydrocarbons up the well. 
   
   
       3 . The method in accordance with  claim 1  comprising the further step of applying microwave energy to form a phase boundary extending away from the antenna. 
   
   
       4 . The method in accordance with  claim 1  comprising the further step of applying microwave energy at a sufficient density to vaporize a portion of the material in the phase boundary to create a pressure differential between the area in the phase boundary and the drilled well. 
   
   
       5 . The method in accordance with  claim 1  wherein the hole is drilled in strata with one or more layers of water and one or more layers of oil shale comprising the further steps of sealing one or more of the layers of water before applying the microwave energy. 
   
   
       6 . A method of in-situ extraction of hydrocarbons from a target formation including oil shale, tar sands, heavy oil or residual oil in a petroleum reservoir comprising the steps of positioning a directional radiating antenna in the target formation applying sufficient microwave energy through the antenna to the target formation to vaporize material in the target formation to fracture the rock in the target formation thereby increasing the intrinsic permeability to allow hydrocarbons to flow toward the antenna. 
   
   
       7 . A method of extracting hydrocarbons from subsurface target formations, such as oil shale, tar sands, heavy oil, and residual oil from petroleum reservoirs comprising the step of radiating directed electromagnetic energy at microwave frequencies into the target formation. 
   
   
       8 . The method in accordance with  claim 7  comprising the further step of producing superheated steam or other critical or super critical fluids in the target formation to enhancce hydrocarbon removal rates. 
   
   
       9 . The method in accordance with  claim 7  comprising the further steps of drilling a bore hole into the rock of the target formation, transferring microwave power from a portable surface source to a radiating antenna in the target formation, radiating the microwave power via the antenna at sufficient power density and frequency to selectively heat water and hydrocarbons in the target formation for extraction and treatment at the surface. 
   
   
       10 . Apparatus for extracting hydrocarbons from subsurface target formation comprising a source of microwave power equal to or greater than one-half Megawatt, a directional antenna positioned in the target formation, and a waveguide coupling the microwave energy from the source to the antenna. 
   
   
       11 . Apparatus in accordance with  claim 10  further comprising a dummy load and a recirculator to shunt reflected energy to the dummy load. 
   
   
       12 . Apparatus in accordance with  claim 10  further comprising a mode converter between the source and the antenna. 
   
   
       13 . Apparatus in accordance with  claim 12  further comprising a rotator between the mode converter and the antenna for rotation of the antenna to change the direction of radiation. 
   
   
       14 . Apparatus in accordance with  claim 10  wherein the antenna is a phase array antenna. 
   
   
       15 . Apparatus in accordance with  claim 10  wherein the antenna is a radiating slotted antenna. 
   
   
       16 . Apparatus in accordance with  claim 10  wherein the source operates at a frequency near or at 2.45 Gigahertz. 
   
   
       17 . Apparatus in accordance with  claim 10  wherein the apparatus is field portable. 
   
   
       18 . A system for in-situ extraction of hydrocarbons from a target formation comprising a hole drilled down to and including the target formation, a casing in the hole, the casing being closed at the top above ground and having a well screen of low dielectric material at the lower end in the target formation, a source of microwave energy, a radiating antenna positioned in the casing at the target formation, means for coupling the source to the antenna and a valve coupled to the top of the casing to control the pressure in the hole.