Oil recovery system and method
First Claim
1. An oil recovery system comprising a well casing, means within said casing for conducting fluid upwardly through said casing from a subterranean petroleum-bearing formation, means externally located with respect to said casing for generating microwave energy, means within said casing for transmitting said microwave energy downwardly within said casing from said externally located generating means, and a radiator unit connected to the lower end of said transmitting means having a plurality of vertically spaced slots therein, said slotted radiator unit projecting beneath the lower end of said casing for propagating at least some of said microwave energy into said subterranean formation via said slots.
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Accused Products
Abstract
A slotted radiating unit is lowered into a well casing of limited cross section, and microwave energy is fed downwardly thereto via a transmission line also installed in the casing. Two embodiments of the radiating unit are disclosed, and two embodiments of the transmission line are also described. Depending upon the subterranean conditions, periods of on and off microwave propagation are sometimes employed; in some instances dual radio frequencies are utilized to enhance petroleum flow. Subsurface sensors are made use of to control the ground level radio frequency generator (or generators).
194 Citations
53 Claims
- 1. An oil recovery system comprising a well casing, means within said casing for conducting fluid upwardly through said casing from a subterranean petroleum-bearing formation, means externally located with respect to said casing for generating microwave energy, means within said casing for transmitting said microwave energy downwardly within said casing from said externally located generating means, and a radiator unit connected to the lower end of said transmitting means having a plurality of vertically spaced slots therein, said slotted radiator unit projecting beneath the lower end of said casing for propagating at least some of said microwave energy into said subterranean formation via said slots.
- 9. In a system for in situ heating underground hydrocarbonaceous material via a bore hole of restricted cross section, a waveguide having a width somewhat less than that of the bore hole, said waveguide having a longitudinal groove in one wall thereof, and tubing received in said groove and extending therealong.
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15. An oil recovery method comprising the step of disposing production tubing and a radio frequency transmission line in a well casing, at least portions of said tubing and said transmission line being in engagement, said transmission line including a waveguide having a plurality of vertically spaced slots therein.
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16. An oil recovery method comprising the steps of radiating microwave energy into a petroleum-bearing subterranean formation for a first period of time, discontinuing the radiating of any microwave energy into said subterranean formation for a second period of time, determining the rate of fluid flow resulting from the radiation of microwave energy into said subterranean formation, and discontinuing the radiation of said microwave energy after a first rate of fluid flow has been determined.
- 17. An oil recovery system comprising a well casing, means within said casing for conducting fluid upwardly through said casing from a subterranean petroleum-bearing formation, said fluid conducting means including metal tubing through which the fluid flows, means within said casing for transmitting microwave energy downwardly within said casing including a waveguide provided with a metal wall having a portion thereof engaging a portion of said metal tubing, said wall having a groove therein and a portion of said tubing residing in said groove, and a radiator unit connected to the lower end of said transmitting means having a plurality of slots therein, said slotted radiator unit projecting beneath the lower end of said casing for propagating at least some of said microwave energy into said subterranean formation via said slots.
- 24. An oil recovery system comprising a well casing, means within said casing for conducting fluid upwardly through said casing from a subterranean petroleum-bearing formation, means within said casing for transmitting microwave energy downwardly within said casing, a radiator unit connected to the lower end of said transmitting means having a plurality of slots therein, said slotted radiator unit projecting beneath the lower end of said casing for propagating at least some of said microwave energy into said subterranean formation via said slots, and first and second radio frequency generating means connected to the upper end of said transmitting means, said first generating means supplying microwave energy at a relatively high frequency and said second generating means supplying microwave energy to said radiator unit at a relatively low frequency.
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26. An oil recovery system comprising a well casing, means within said casing for conducting fluid upwardly through said casing from a subterranean petroleum-bearing formation, means within said casing for transmitting microwave energy downwardly within said casing, a radiator unit connected to the lower end of said transmitting means having a plurality of slots therein, said slotted radiator unit projecting beneath the lower end of said casing for propagating at least some of said microwave energy into said subterranean formation via said slots, means for generating said microwave energy, means for causing said radiator unit to propagate microwave energy during a first predetermined period and to cause said radiator unit to discontinue propagating of microwave energy during a second predetermined period, said second predetermined period being longer than said first predetermined period, and means for monitoring the flow of fluid through said tubing during both of said periods.
- 27. An oil recovery system comprising a well casing, means within said casing for conducting fluid upwardly through said casing from a subterranean petroleum-bearing formation, means within said casing for transmitting microwave energy downwardly within said casing, and a radiator unit connected to the lower end of said transmitting means having a plurality of slots therein, said slotted radiator unit projecting beneath the lower end of said casing for propagating at least some of said microwave energy into said subterranean formation via said slots, said radiator unit including a plurality of vertically spaced, angularly oriented slots.
- 35. An oil recovery system comprising a well casing, means within said casing for conducting fluid upwardly through said casing from a subterranean petroleum-bearing formation, means within said casing and transmitting microwave energy downwardly within said casing, a radiator unit connected to the lower end of said transmitting means having a plurality of slots therein, said slotted radiator unit projecting beneath the lower end of said casing for propagating at least some of said microwave energy into said subterranean formation via said slots, said radiator unit including a waveguide having a relatively flat vertical wall, said vertically spaced slots being located in said relatively flat vertical wall.
- 39. An oil recovery system comprising a well casing, means within said casing for conducting fluid upwardly through said casing from a subterranean petroleum-bearing formation, means within said casing for transmitting microwave energy downwardly within said casing, a radiator unit connected to the lower end of said transmitting means having a plurality of slots therein, said slotted radiator unit projecting beneath the lower end of said casing for propagating at least some of said microwave energy into said subterranean formation via said slots, said transmitting means including a first waveguide, and said slotted radiator unit including a second waveguide having a relatively flat first wall, said slots being in said first wall.
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45. In a system for in situ heating underground hydrocarbonaceous material via a bore hole of restricted cross sections, a waveguide having a width somewhat less than that of the bore hole, said waveguide having a plurality of slots in one wall thereof, and a probe extending inwardly from said wall at generally right angles thereto.
- 46. An oil recovery method comprising the step of disposing production tubing and a radio frequency transmission line in a well casing, at least portions of said tubing and said transmission line being in engagement, attaching a slotted radiator unit to said transmission line having a plurality of vertically oriented slots, first introducing said radiator unit into said well casing followed by said transmission line and tubing, and tuning at least one of said slots for the particular characteristics of the subterranean oil-bearing formation with which said slot is aligned.
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48. An oil recovery method comprising the step of radiating microwave energy at a first frequency into a petroleum-bearing subterranean formation at one depth, and radiating microwave energy at a second frequency into the subterranean formation at a different depth, said first and second frequencies differing from each other.
- 49. An oil recovery system comprising a well casing, means within said casing for conducting fluid upwardly through said casing from a subterranean petroleum-bearing formation, means externally located with respect to said casing for generating microwave energy, means within said casing for transmitting said microwave energy downwardly within said casing from said externally located generating means, and a radiator unit connected to the lower end of said transmitting means including a metal cylinder and a centrally located conductor therewithin, said metal cylinder having at least one slot therein, and a shorting device associated with said slot for correlating the impedance matching of the radiator unit with the particular characteristics of the underground oil-bearing formation.
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53. An oil recovery system comprising a well casing, means within said casing for conducting fluid upwardly through said casing from a subterranean petroleum-bearing formation, means externally located with respect to said casing for generating microwave energy, means within said casing for transmitting said microwave energy downwardly within said casing from said externally located generating means, and slotted means at the lower end of said transmitting means for propagating at least some of said microwave energy into said subterranean formation at a plurality of vertically spaced locations.
Specification