Apparatus and method for radio frequency heating of hydrocarbonaceous earth formations including an impedance matching technique
First Claim
1. An impedance matching network having a first port connected to a high power radio frequency transmitter and a second port connected to a transmission line including conductors at least partially embedded in a hydrocarbonaceous earth formation to be heated, comprising a first and a second variable reactance means, said first and second variable reactance means comprising respectively, first and second independently variable capacitors, connected in series to form an upper leg of a T network;
- and a third variable reactance means, said third variable reactance means comprising a third independently variable capacitor, in shunt between the first and second variable reactance means to form the central leg of a T network, wherein the impedance presented by said transmission line during the heating of the hydrocarbonaceous formation is matched by holding one of the variable reactances at its minimum or maximum and adjusting the other two variable reactance means.
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Abstract
The disclosure relates to a technique for radio frequency heating of hydrocarbonaceous earth formations in which a high power radio frequency transmitter is impedance matched to a transmission line including a plurality of conductors at least partially embedded in the formation to be heated. The impedance matching may be effected by a "T" network having three variable reactances. In accordance with the teachings of the present invention, continuous variations of impedance, of the type encountered during the heating of the formation, may be matched in unambiguously defined Smith chart regions by varying two of the three reactances to minimize reflected power from the transmission line.
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9 Claims
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1. An impedance matching network having a first port connected to a high power radio frequency transmitter and a second port connected to a transmission line including conductors at least partially embedded in a hydrocarbonaceous earth formation to be heated, comprising a first and a second variable reactance means, said first and second variable reactance means comprising respectively, first and second independently variable capacitors, connected in series to form an upper leg of a T network;
- and a third variable reactance means, said third variable reactance means comprising a third independently variable capacitor, in shunt between the first and second variable reactance means to form the central leg of a T network, wherein the impedance presented by said transmission line during the heating of the hydrocarbonaceous formation is matched by holding one of the variable reactances at its minimum or maximum and adjusting the other two variable reactance means.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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