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Apparatus and method for generating electrical power through the reduction of a wellhead pressure. In accordance with various embodiments, a wellhead coupled to a subterranean formation supplies a first conduit with pressurized natural gas at a first pressure. A turbine receives the pressurized natu

Apparatus and method for generating electrical power through the reduction of a wellhead pressure. In accordance with various embodiments, a wellhead coupled to a subterranean formation supplies a first conduit with pressurized natural gas at a first pressure. A turbine receives the pressurized natural gas and induces a pressure drop in the gas as the gas induces mechanical rotation of the turbine. A mechanical linkage is coupled to the turbine, and an electrical generator is coupled to the mechanical linkage. The electrical generator generates electrical power responsive to the mechanical rotation of the turbine. The turbine and the electrical generator are operated to maintain an exit pressure of the pressurized natural gas at a predetermined second pressure less than the first pressure.

대표청구항 ▼

1. An apparatus comprising: a wellhead coupled to a subterranean formation which supplies pressurized natural gas to a first conduit at a first pressure;a turbine configured to receive the pressurized natural gas from the first conduit and to induce a pressure drop in the gas as the gas induces mech

1. An apparatus comprising: a wellhead coupled to a subterranean formation which supplies pressurized natural gas to a first conduit at a first pressure;a turbine configured to receive the pressurized natural gas from the first conduit and to induce a pressure drop in the gas as the gas induces mechanical rotation of the turbine;an electrical generator which generates electrical power responsive to the mechanical rotation of the turbine, wherein the turbine and the electrical generator maintain an exit pressure of the pressurized natural gas at a predetermined second pressure less than the first pressure; anda mechanical linkage between the turbine and the electrical generator, the mechanical linkage comprising a first hydraulic motor coupled to the turbine, a second hydraulic motor coupled to the electrical generator, and a closed conduit which accommodates a volume of pressurized hydraulic fluid, wherein the first hydraulic motor rotates responsive to mechanical rotation of the turbine to initiate a flow of the pressurized hydraulic fluid, the flow of pressurized hydraulic fluid initiating rotation of the second hydraulic motor, and the rotation of the second hydraulic motor initiating rotation of the electrical generator. 2. The apparatus of claim 1, further comprising a choke connected in series and downstream from the turbine which cooperates with the turbine to reduce the pressure of said natural gas to the second pressure. 3. The apparatus of claim 1, further comprising a choke connected in parallel with the turbine which cooperates with the turbine to reduce the pressure of said natural gas to the second pressure. 4. The apparatus of claim 1, further comprising a bypass path for the pressurized natural gas so that the pressurized natural gas temporarily bypasses the turbine while the turbine is offline, the bypass path including a choke which operates to reduce the pressurized natural gas to the second pressure. 5. The apparatus of claim 1, further comprising a first pressure sensor which generates a first pressure measurement signal indicative of the first pressure, and a second pressure sensor which generates a second pressure measurement signal indicative of the second pressure. 6. The apparatus of claim 5, further comprising a programmable controller which, responsive to the first and second pressure measurement signals, adjusts a system parameter to maintain the second pressure at said predetermined level. 7. The apparatus of claim 1, further comprising a direct-current (DC) to alternating-current (AC) converter, wherein the electrical generator generates DC electrical power which is rectified to AC electrical power by the converter. 8. The apparatus of claim 1, further comprising a battery adjacent the generator which temporarily stores said power generated by the electrical generator. 9. The apparatus of claim 1, further comprising an electrical heater adjacent the turbine to supply heat to the turbine during operation, the electrical heater generating said heat from electrical power generated by the electrical generator. 10. A method comprising: receiving pressurized natural gas from a subterranean formation via a wellhead conduit which supplies said gas at a wellhead pressure;directing the gas through a turbine to induce a pressure drop in the gas and to induce mechanical rotation of the turbine; andusing an electrical generator coupled to the turbine via a mechanical linkage to generate electrical power responsive to said mechanical rotation of the turbine, wherein the turbine and the electrical generator maintain the gas at a predetermined exit pressure less than the wellhead pressure, wherein the mechanical linkage comprises a first hydraulic motor coupled to the turbine, a second hydraulic motor coupled to the electrical generator, and a closed conduit which accommodates a volume of pressurized hydraulic fluid, wherein the first hydraulic motor rotates responsive to mechanical rotation of the turbine to initiate a flow of the pressurized hydraulic fluid, wherein the flow of pressurized hydraulic fluid initiates rotation of the second hydraulic motor, and wherein the rotation of the second hydraulic motor initiates rotation of the electrical generator. 11. The method of claim 10, wherein the directing step further comprises directing the gas through a choke connected in series with the turbine to reduce the pressure of said natural gas to the exit pressure. 12. The method of claim 10, further comprising using a first pressure sensor to sense the wellhead pressure of the gas and a second pressure sensor to sense the exit pressure of the gas. 13. The method of claim 12, further comprising utilizing a programmable controller to adjust a system parameter to maintain the exit pressure at a predetermined level responsive to the first and second pressure sensors. 14. The method of claim 10, in which the electrical generator generates direct current (DC) electrical power, and the method further comprises converting the DC electrical power to produce alternating current (AC) power. 15. The method of claim 10, further comprising temporarily storing the electrical power generated by the electrical generator in a battery. 16. The method of claim 10, further comprising using an electrical heater adjacent the turbine to supply heat to the turbine during operation, the electrical heater generating said heat from electrical power generated by the electrical generator. 17. An apparatus comprising: a turbine which mechanically rotates in response to a flow of pressurized natural gas from a conduit connected to a natural gas wellhead;a mechanical linkage comprising a first hydraulic motor connected to the turbine, a second hydraulic motor and a closed conduit connected between the first and second hydraulic motors, the closed conduit accommodating a volume of pressurized hydraulic fluid; andan electrical generator connected to the second hydraulic motor, wherein the first hydraulic motor rotates responsive to mechanical rotation of the turbine to initiate a flow of the pressurized hydraulic fluid, the flow of pressurized hydraulic fluid initiating rotation of the second hydraulic motor, and the rotation of the second hydraulic motor initiating rotation of the electrical generator to generate electrical power. 18. The apparatus of claim 17, wherein rotation of the turbine induces a first pressure drop in the flow of natural gas, and wherein the apparatus further comprises a choke connected to the turbine to induce a second pressure drop in the flow of natural gas. 19. The apparatus of claim 18, wherein the flow of natural gas is at a pressure of from 5,000 pounds per square inch (psi) to 15,000 psi. 20. The apparatus of claim 17, further comprising an electrical heater adjacent the turbine to supply heat to the turbine during operation, the electrical heater generating said heat from electrical power generated by the electrical generator.