Multi-fluid renewable geo-energy systems and methods

Patent metadata

Field	Value
Publication number	US-10995972-B2
Application number	US-201715642045-A
Country	US
Kind code	B2
Filing date	Jul 5, 2017
Priority date	Jun 20, 2014
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A geo-energy production system and method extracts thermal energy from a reservoir formation, and stores either thermal waste heat or excess heat in a storage zone of the reservoir formation. A compressed fluid injection injects an unheated, compressed working fluid into the storage zone. A fluid injection well injects a working fluid laden with thermal waste heat or excess heat into the storage zone. The storage zone is located below a caprock layer and above a native brine zone of the reservoir formation and is partially circumscribed by a hot brine storage zone. The compressed working fluid assists with a withdrawal of pressurized brine residing below and/or to the sides of the storage zone. A compressed CO2, N2, or air production well helps to remove compressed working fluid from the storage zone for use in power production.

First claim

What is claimed:

1. A method for geothermal energy storage using a geothermal reservoir formation, the geothermal reservoir formation including a storage reservoir of brine located below a caprock layer, and above a bedrock layer, the method comprising:
performing a thermal recharge operation by which brine is heated and pressurized to form heated and pressurized brine, and then injected through a hot brine/cold-supplemental working fluid injection well extending through the reservoir formation and into the storage reservoir, the heated and pressurized brine increasing a temperature of the storage reservoir to cause the storage reservoir to act as a geothermal resource;
performing a supplemental working fluid recharge operation during which a supplemental working fluid is compressed and then injected through the hot brine/cold-supplemental working fluid injection well into the storage reservoir, to mix with the heated and pressurized brine, to form a mixture of heated and pressurized brine and heated supplemental working fluid;
performing a first portion of an energy discharge operation in which the mixture of heated and pressurized brine and heated supplemental working fluid is withdrawn from the storage reservoir through a hot brine/hot supplemental working fluid production well in communication with the storage reservoir and fed into a fluid separator, an output of the fluid separator producing separate streams of hot brine and heated supplemental working fluid;
performing a second portion of the energy discharge operation by using a heat exchanger and energy producing subsystem to simultaneously receive the separate streams of hot brine and heated supplemental working fluid and to use the simultaneously received separate streams of hot brine and heated supplemental working fluid for energy production;
after using the simultaneously received separate streams of heated supplemental working fluid and the hot brine for the energy production, discharging cold brine and cold supplemental working fluid from the heat exchanger and energy producing subsystem as byproducts of the energy discharge operation;
then performing at least one of a re-heating operation ora repressurizing operation on either the cold brine or the cold supplemental working fluid to create either a new quantity of hot brine or a new quantity of pressurized supplemental working fluid; and
injecting either the new quantity of hot brine or the new quantity of pressurized supplemental working fluid into the storage reservoir, using the hot brine/cold-supplemental working fluid injection well, to further carry out an additional thermal recharge operation or an additional supplemental working fluid recharge operation.

2. The method of claim 1 , wherein injection of the heated and pressurized brine and injection of the supplemental working fluid is performed in an alternating manner.

3. The method of claim 1 , wherein the separate stream of hot brine output from the fluid separator is fed into at least one heat exchanger used to help perform the energy discharge operation, to further help heat the hot supplemental working fluid during the energy discharge operation.

4. The method of claim 3 , further comprising feeding the hot brine which has been cooled by the heat exchanger and energy producing subsystem into a cold brine holding tank or staging pond prior to performing the re-heating operation.

5. The method of claim 1 , wherein the output of the fluid separator is heated CO 2 , and the heated CO 2 is fed into the energy producing subsystem used for the energy production.

6. The method of claim 1 , wherein performing a supplemental working fluid recharge operation comprises injecting at least one of CO 2 , N 2 or air into the hot brine/cold-supplemental working fluid injection well.

7. The method of claim 1 , further comprising a brine production well formed in the reservoir formation for removal of only hot brine.

8. The method of claim 7 , further comprising a heat source for further heating the hot brine removed from the brine production well and routing the further heated hot brine into the hot brine/cold-supplemental working fluid injection well.

9. The method of claim 1 , wherein injecting the supplemental working fluid comprises injecting at least one of CO 2 , N 2 or compressed air.

Assignees

• L Livermore Nat Security Llc

Inventors

• Buscheck Thomas A

Classifications

• F01K25/103

  Carbon dioxide (F01K25/065 takes precedence) · CPC title

• F28D20/0052

  using the ground body or aquifers as heat storage medium · CPC title

• F24T10/20 Primary

  using underground water as working fluid; using working fluid injected directly into the ground, e.g. using injection wells and recovery wells · CPC title

• Y02E70/30

  Systems combining energy storage with energy generation of non-fossil origin · CPC title

• F24T2010/56

  Control arrangements · CPC title