# US 8,464,792 B2 · Conduction convection reflux retorting process > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,464,792 B2 - Document ID: US8464792B2 - Status: Granted - Kind: B2 - Application number: 12/779,826 - Filed: 2010-05-13 - Published: 2011-10-27 - Granted: 2013-06-18 - Earliest claimed: 2010-04-27 - Assignees: American Shale Oil, LLC - Applicants: Alan K. Burnham; Roger L. Day; P. Henrick Wallman; James R. McConaghy - Inventors: Alan K. Burnham; Roger L. Day; P. Henrick Wallman; James R. McConaghy - Web page: https://patentgrep.com/patent/US8464792B2 ## CPC - E21B 43/121: {Lifting well fluids (monitoring of down-hole pump systems E21B47/008)} - E21B 36/00: Heating, cooling or insulating arrangements for boreholes or wells, e.g. for use in permafrost zones - E21B 36/04: using electrical heaters - E21B 43/24: using heat, e.g. steam injection - E21B 43/2401: {by means of electricity} - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract A sub-surface hydrocarbon production system comprising an energy delivery well extending from the surface to a location proximate a bottom of the hydrocarbons to be produced. A production well extends from the surface to a location proximate the hydrocarbon and a convection passage extends between the energy delivery well and the production well thereby forming a convection loop. The energy delivery well and the production well intersect at a location proximate the hydrocarbon such that the convection loop is in the form of a triangle. Preferably, the convection passage extends upwardly from a point at which the convection passage intersects the production well. The system also includes a heater, such as an electric heater or down-hole burner, disposed in the energy delivery well. ## Claims ### Claim 1 A sub-surface hydrocarbon production system, comprising: an energy delivery well having a proximate end and a distal end and extending from the surface to a location proximate a bottom of the hydrocarbons; a production well having a proximate end and a distal end and extending from the surface to a location proximate the hydrocarbon such that the energy delivery well and the production well are in fluid communication towards their distal ends; and a convection passage extending between said energy delivery well and said production well thereby forming a convection loop. ### Claim 2 (depends on 1) A production system according to claim 1 wherein said energy delivery well and said production well intersect such that said convection loop is in the form of a triangle. ### Claim 3 (depends on 2) A production system according to claim 2 wherein said convection passage extends upwardly from a point at which said convection passage intersects said production well. ### Claim 4 (depends on 1) A production system according to claim 1 wherein said energy delivery well is an L-shaped well intersecting said production well such that said convection loop is in the form of a quadrilateral. ### Claim 5 (depends on 1) A production system according to claim 1 including a pair of convection passages extending between said energy delivery well and said production well such that said convection loop is in the form of a quadrilateral. ### Claim 6 (depends on 5) A production system according to claim 5 wherein said pair of convection passages comprise two deviated boreholes emanating from a branch in a single deviated well. ### Claim 7 (depends on 5) A production system according to claim 5 wherein said energy delivery well and said production well are substantially vertically oriented. ### Claim 8 (depends on 1) A production system according to claim 1 including a heater disposed in said energy delivery well operative to heat the hydrocarbon to produce a pool of liquid hydrocarbon and hydrocarbon vapors, and wherein said convection passage is configured such that hydrocarbon condensate, formed in said convection loop from said hydrocarbon vapors, is returned to the pool of liquid hydrocarbon by the force of gravity. ### Claim 9 (depends on 8) A production system according to claim 8, wherein said heater is a down hole burner. ### Claim 10 A sub-surface oil shale production system, comprising: a production well extending vertically from the surface to a location proximate the oil shale; an energy delivery well extending from the surface along a path including an arcuate portion, wherein said arcuate portion intersects said production well at a location proximate a bottom of the oil shale; a heater disposed in said energy delivery well operative to heat the oil shale; and a convection passage extending between said energy delivery well and said production well thereby forming a convection loop, said convection passage extending upwardly from the intersection of said arcuate portion and said production well. ### Claim 11 (depends on 10) A production system according to claim 10 wherein said heater is operative to heat the oil shale to form an oil pool and oil vapors, and including a throttling device adapted to selectively restrict the release of said oil vapors from said production well thereby maintaining the pressure of the convection loop at a desired pressure. ### Claim 12 (depends on 10) A production system according to claim 10 wherein said heater is located below an interval of oil shale to be produced. ### Claim 13 A process for retorting and extracting sub-surface hydrocarbons, comprising: drilling an energy delivery well extending from the surface to a location proximate a bottom of the hydrocarbons; drilling a production well extending from the surface to a location proximate the hydrocarbon; forming a convection passage that extends between said energy delivery well and said production well thereby forming a convection loop; heating the hydrocarbons to form an oil pool and oil vapors; maintaining the pressure of the convection loop at a level that is sufficient to condense said oil vapors into oil condensate; and recycling said oil vapors and said oil condensate in said convection loop. ### Claim 14 (depends on 13) The process according to claim 13 including maintaining the pressure in said convection loop by selectively restricting the release of oil vapor from the production well. ### Claim 15 (depends on 14) The process according to claim 14 including heating said portion of oil to be returned to the oil pool. ### Claim 16 (depends on 13) The process according to claim 13 including removing to the surface oil from said oil pool and returning a portion of said oil removed to the surface in order to maintain said oil pool at a desired level relative said energy delivery well. ### Claim 17 (depends on 16) The process according to claim 16 including selecting a distillation cut of the portion of oil to be returned to said oil pool as a function of the pressure maintained in the convection loop. ### Claim 18 (depends on 16) The process according to claim 16 wherein the oil returned from the surface cools the oil vapors and causes additional oil to condense and return to the oil pool by gravity-driven flow. ### Claim 19 (depends on 16) The process according to claim 16 including controlling the boiling point of the oil pool by selecting a distillation cut of the portion of oil to be returned to said oil pool.