Richard H Snow
Engineers at Cornell Ave, Chicago, IL

4140180, Feb 20, 1979

Aug 29, 1977

5/828904

Jack Bridges - Park Ridge IL
Allen Taflove - Chicago IL
Richard Snow - Chicago IL

IIT Research Institute - Chicago IL

E21B 4324

166248

The disclosure describes a technique for uniform heating of relatively large blocks of hydrocarbonaceous formations in situ using radio frequency (RF) electrical energy that is substantially confined to the volume to be heated and effects dielectric heating of the formations. An important aspect of the disclosure relates to the fact that certain hydrocarbonaceous earth formations, for example raw unheated oil shale, exhibit dielectric absorption characteristics in the radio frequency range. In accordance with the system of the invention, a plurality of conductors are inserted in the formations and bound a particular volume of the formations. The phrase "bounding a particular volume" is intended to mean that the volume is enclosed on at least two sides thereof. Electrical excitation is provided for establishing alternating electric fields in the volume. The frequency of the excitation is selected as a function of the dimensions of the volume so as to establish a substantially non-radiating electric field which is substantially confined in the volume.

4485868, Dec 4, 1984

Sep 29, 1982

6/428081

Guggilam C. Sresty - Chicago IL
Harsh Dev - Chicago IL
Richard H. Snow - Chicago IL
Jack E. Bridges - Park Ridge IL

IIT Research Institute - Chicago IL

E21B 4324

166248

A method of electromagnetic heating in situ recovers liquid hydrocarbons from an earth formation containing viscous hydrocarbonaceous liquid and water in an inorganic matrix where the formation is substantially impermeable to fluids under native conditions. A block of the earth formation is substantially uniformly heated with electromagnetic power to a temperature at which the viscous hydrocarbonaceous liquid is relatively fluid and a portion of the water vaporizes to water vapor at a pressure sufficient to overcome the capillary pressure of the liquid in the matrix. Water vapor thereupon escaping from the block under such pressure is recovered with hydrocarbonaceous liquid driven thereby. The magnitude of the electromagnetic power is controlled to limit the current recovery ratio of water vapor to hydrocarbonaceous liquid below a predetermined limit assuring substantial recovery of the hydrocarbonaceous liquid prior to the driving off of substantially all the water.

4485869, Dec 4, 1984

Oct 22, 1982

6/435979

Guggilam C. Sresty - Chicago IL
Richard H. Snow - Chicago IL
Jack E. Bridges - Park Ridge IL

IIT Research Institute - Chicago IL

E21B 4324

166248

A method of electromagnetic heating in situ recovers liquid hydrocarbons from an oil shale formation containing kerogen in an inorganic matrix where the formation is substantially impermeable to fluids under native conditions. A block of the oil shale formation is substantially uniformly heated in situ with electromagnetic power to a temperature of about 275. degree. C. where there is pyrolysis of a portion of the kerogen to gas and shale oil at a pressure sufficient to overcome the capillary pressure of the shale oil in the matrix, thereby providing substantial fluid permeability to the formation. The gas thereupon escaping from said block and the shale oil driven thereby are recovered, thereby further increasing the permeability of the formation. The magnitude of the electromagnetic power is controlled to raise the temperature of the block relatively slowly to increase the rate of pyrolysis of the kerogen as the permeability of the formation increases to produce gas at pressures above the necessary to overcome the capillary pressure and below that at which there is substantial escape of the gas bypassing shale oil within the formation rather than driving the oil before it.