Method and apparatus for steam generation from isothermal geothermal reservoirs

A method of constructing a geothermal energy conversion system that converts energy from an isothermal zone beneath the surface of the Earth, the isothermal zone comprising a mixture of liquid brine and vapor brine where the liquid brine has an upper surface level separating the liquid brine and the vapor brine, comprising the steps of:

• forming a geothermal well in communication with the isothermal zone;
• creating a casing for the well that defines a space within the well that extends into the isothermal zone;
• forming perforations in the walls of the casing below a level at which the liquid brine surface level will contact the casing so liquid brine enters through the perforations into the space;
• placing a heat exchanger within the space at a depth below the liquid brine surface level;
• connecting an inlet pipe and an outlet pipe to the heat exchanger;
• placing a system of pumps and valves in fluid communication with the inlet pipe, the system of pumps and valves being configured to regulate at least one of the pressure or flow rate of fluid flowing into and through the heat exchanger;
• and
• sealing the casing to form brine vapor within the space while still communicating fluid to and from the heat exchanger through the sealing.

A method for regulating the flow rate and pressure of a fluid flowing through a heat exchanger in a geothermal well, comprising the steps of:

• forming a first fluid stream from a fluid source, by pumping and pressurizing fluid from the fluid source with a pump;
• controlling a first valve in parallel with the pump, to regulate the pressure of the fluid as the fluid exits the pump;
• controlling a second valve, downstream of the pump, to achieve a desired flow rate of the fluid in the first fluid stream;
• controlling a third valve, downstream of the pump, to achieve a desired pressure of the fluid in the first fluid stream;
• dividing the first fluid stream at a dividing junction into a second fluid stream and a third fluid stream, the second fluid stream entering the heat exchanger and the third fluid stream returning to the fluid source;
• controlling a fourth valve in the second fluid stream, between the dividing junction and the heat exchanger, to regulate the flow rate of the fluid in the second fluid stream;
• controlling a fifth valve in the third fluid stream, between the dividing junction and the fluid source, to regulate the flow rate of the fluid in the third fluid stream;
• achieving a desired flow rate in the second fluid stream by incrementally opening the fourth valve from a closed position and incrementally closing the fifth valve from an open position;
• controlling a sixth valve, downstream of the exit of the heat exchanger, to regulate the pressure of the fluid as it exits the heat exchanger;
• incrementally increasing the flow rate of the fluid entering the heat exchanger, by controlling the fourth valve and the fifth valve, and monitoring a correspondingly increasing flow rate of the fluid exiting the heat exchanger;
• and
• discontinuing the incremental increase when the flow rate of the fluid exiting the heat exchanger ceases to increase.