Microwave process for intrinsic permeability enhancement and hydrocarbon extraction from subsurface deposits
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, tar sands, or conventional oil reservoirs comprising the steps of drilling a hole down to the selected layer of hydrocarbons and applying continuous microwave energy at frequencies greater than 2 GHz to a directional antenna positioned in the-selected layer and launching a narrow phase boundary that reduces the viscosity of the hydrocarbons to permit them 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 in a narrow migrating phase boundary extending away from the antenna and creating a sufficient pressure differential between the phase boundary and the drilled well to push the hydrocarbons to the well.
3. The method in accordance with claim 1 comprising the further step of applying microwave energy at a density greater than ½ megawatt 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.
4. Apparatus for extracting hydrocarbons from a subsurface target formation comprising a continuous source of microwave power equal to or greater than one-half Megawatt, a directional antenna positioned in the target formation, a waveguide or coaxial cable coupling the microwave energy from the source to the antenna, and a phase boundary radiating away from the antenna for reducing the viscosity of the hydrocarbons.
5. Apparatus in accordance with claim 4 further comprising a dummy load and a recirculator to shunt reflected energy to the dummy load.
6. Apparatus in accordance with claim 4 further comprising a mode converter between the source and the antenna.
7. Apparatus in accordance with claim 6 further comprising a rotator between the mode converter and the antenna for rotation of the antenna to change the direction of radiation.
8. Apparatus in accordance with claim 4 wherein the source operates at a frequency above 2 Gigahertz.
9. Apparatus in accordance with claim 4 wherein the apparatus is field portable.
10. 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 loss 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 for creating and launching a phase boundary in the target formation and a valve coupled to the top of the casing to control the pressure in the hole.