In situ radio frequency selective heating process
AssigneeRaytheon Company
InventorsRaymond S. Kasevich, Myer Kolker, Arthur S. Dwyer
Life of this patent
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Abstract
The process and apparatus for extracting the products of kerogen in situ from an oil shale body by supplying energy selectively to the kerogen by high frequency electric fields in the frequency range between 100 kilohertz and 1000 megahertz at an intensity which heats the kerogen to a temperature range between 250.degree. C. and 500.degree. C. to allow pyrolysis of the kerogen prior to substantial heat transfer to the surrounding mineral portions of the oil shale.
Claims29
The method of producing organic liquids and/or gaseous products from organic compounds contained in a mineral formation comprising the steps of:
- reducing the alternating current electrical conductivity of a region of said mineral formation comprising reducing the amount of liquid water in said formation region;
- supplying an electric field having a frequency in the range between 100 kilohertz to 1000 megahertz to said region of said formation at an intensity which heats said organic compounds in said region to temperatures in the range between 200.degree. C. and 500.degree. C. where substantial conversion of said compounds to said products occurs while adjacent portions of said formation are heated to temperatures substantially below said first temperature;
- and
- producing products derived from said organic compounds by the flow of said products through said formation .
A system for producing subsurface heating of a formation comprising:
- a plurality of groups of spaced radiators extending through an overburden into a region to be heated;
- and
- means for heating predominantly organic portions of said formation at a more rapid rate than said heat is transferred by conduction from said predominantly organic portions to predominantly inorganic portions of said formation adjacent to said predominantly organic portions comprising supplying said radiators with alternating current electrical energy until the electrical conductivity of said predominantly organic portions increases substantially from the electrical conductivity of said predominantly organic portions of said formation at lower temperatures.
A system for producing subsurface heating of a formation comprising:
- a plurality of groups of spaced radiators extending through an overburden into a region to be heated;
- means for supplying said radiators with electrical energy at intensities and a frequency which produces electrical fields in said formation which heat selected organic portions of said formation at a more rapid rate than said heat is transferred by conduction from said organic portions to predominantly inorganic portions of said formation adjacent to said organic portions until a temperature is reached where the electrical conductivity of said selected organic portions is different from the electrical conductivity of similar organic portions of said formation at lower temperatures;
- and
- said radiators being positioned on the order of a half wavelength apart of said frequency in said formation.
The method of producing organic liquid and gaseous products from kerogen contained in oil shale comprising the steps of:
- supplying thermal energy to at least a portion of said oil shale to remove liquid water from said portion;
- heating a region of said kerogen in said portion to a temperature in the range between 250.degree. C. and 500.degree. C. by subjecting said region of said oil shale to a time varying electric field having a frequency which heats said kerogen more rapidly than the adjacent shale;
- and
- collecting the products of conversion of said kerogen after a sufficient time has passed to allow a substantial portion of said kerogen to be converted to said products prior to transfer of a substantial portion of said heat to said shale.
A method of producing pyrolytic conversion of kerogen in a region of oil shale comprising the steps of:
- reducing the electrical conductivity in a predetermined frequency range of portions of said oil shale which are predominantly shale to a value substantially below said conductivity of portions of said oil shale which are predominantly kerogen comprising reducing the liquid water content of said oil shale;
- and
- pyrolytically converting a substantial portion of said kerogen to other organic compounds by heating said predominantly kerogen portions to temperatures substantially above the temperature of said predominantly shale portions comprising producing to said region electric fields having at least a component in said frequency range.
The method of producing in situ products from kerogen in oil shale by pyrolysis comprising the steps of:
- reducing the liquid water content of a region of oil shale by preheating and/or fracturing said region at temperatures below 300.degree. C.;
- selectively transferring energy to kerogen-rich portions of said region at greater rates than to kerogen-lean portions of said region to heat said kerogen-rich portions to temperatures producing substantial pyrolytic decomposition of said kerogen prior to transfer of the major portion of said heat from said kerogen-rich portions by thermal conduction to adjacent said kerogen-lean portions;
- and
- collecting products derived from said kerogen decomposition in regions of said shale oil body.
The method of processing a body of oil shale comprising:
- processing said body to produce a first region having a first electrical conductivity range throughout a predetermined frequency range;
- and
- radiating electromagnetic wave energy through said first electrical conductivity portion of said body into a portion of said body having a second electrical conductivity higher than said first electrical conductivity.
The method of processing a body of oil shale comprising:
- processing said body to produce in a portion of said body first conductivity for radiating waves over at least a predetermined frequency range;
- radiating electromagnetic wave energy in said frequency range through said first portion of said body into a second portion of said body having a second conductivity which is higher than said first conductivity;
- and
- said energy being radiated into said body from a plurality of radiators spaced in said body by a distance greater than one-tenth wavelength of the frequency of said radiation.
Dependencies are inferred from the claim text.