Well completion converting a hydrocarbon production well into a geothermal well

Patent metadata

Field	Value
Publication number	US-11674718-B2
Application number	US-202217862695-A
Country	US
Kind code	B2
Filing date	Jul 12, 2022
Priority date	May 13, 2020
Publication date	Jun 13, 2023
Grant date	Jun 13, 2023

Abstract

A well completion to convert a hydrocarbon production well into a geothermal well includes flow tubes to transport a working fluid through the well and a heat exchanger at a downhole location coupled to the flow tubes to exchange heat of the formation at the downhole location with the working fluid. A heat exchange fluid surrounds the heat exchanger at the downhole location to be heated by the formation at the downhole location. The heat exchanger heats the working fluid to a state in which the working fluid rises to the surface. At the surface, a power plant uses the heated working fluid to generate work. The working fluid is then cooled and returned to the downhole location to repeat the work generation cycle.

First claim

The invention claimed is:

1. A geothermal well completion comprising:
a subsurface portion configured to be installed downhole within a hydrocarbon production well, the subsurface portion comprising:
an inflow tube configured to flow a working fluid at a first temperature and in a first state from the surface of the well to a bottom hole location within the well,
an outflow tube configured to flow the working fluid at a second temperature greater than the first temperature and in a second state different from the first state from the bottom hole location to the surface of the well, and
a heat exchanger is configured to be installed at the bottom hole location, the heat exchanger comprising an array of tubes fluidically coupled to the inflow tube and the outflow tube, the array of tubes configured to exchange heat of a formation at the bottom hole location of the hydrocarbon production well with the working fluid to heat the working fluid from the first temperature to the second temperature and to change the working fluid from the first state to the second state, wherein the working fluid at the second temperature and in the second state rises to the surface of the hydrocarbon production well through the outflow tube, wherein the heat exchanger comprises a substantially cylindrical outer housing in which the array of tubes is disposed, the outer housing constructed and designed to transfer the heat of the formation to the working fluid flowed through the array of tubes, wherein the outer housing comprises an uphole inlet to which a downhole end of the inflow tube is configured to fluidically couple, wherein the array of tubes comprises:
a first longitudinal tube fluidically coupled to the downhole end of the inflow tube, the first longitudinal tube having a diameter substantially equal to that of the inflow tube, the first longitudinal tube having a length substantially equal to that of the outer housing, the first longitudinal tube disposed substantially along a longitudinal axis of the outer housing; and
a first transverse tube fluidically coupled to an outlet of the first longitudinal tube, the first transverse tube oriented transverse to the longitudinal axis of the outer housing, the first transverse tube configured to divert the working fluid flowed into the outer housing through the first longitudinal tube and in a downhole direction toward a circumferential wall of the outer housing,

wherein the array of tubes comprises a plurality of second longitudinal tubes, each fluidically coupled to the first transverse tube, each having a diameter smaller than a diameter of the first longitudinal tube, each positioned nearer to the circumferential wall of the outer housing compared to the first longitudinal tube, each configured to transfer the heat of the formation from the outer housing to the working fluid as the working fluid flows in an uphole direction; and
a surface portion configured to be installed at a surface of the hydrocarbon production well, the surface portion configured to:
receive, at the surface, the working fluid at the second temperature and in the second state, and
perform work using the working fluid received at the surface.

2. The geothermal well completion of claim 1 , further comprising a second transverse tube fluidically coupled to outlets of the plurality of second longitudinal tubes, the second transverse tube configured to collect the working fluid heated to the second temperature and in the second state, the second transverse tube fluidically coupled to an inlet of the outflow tube to transfer the working fluid from the heat exchanger to the outflow tube.

3. The geothermal well completion of claim 1 , further comprising a sensor system configured to be mounted to the heat exchanger and disposed at the bottom hole location, the sensor system configured to determine fluid properties of the working fluid flowed through the heat exchanger.

4. The geothermal well completion of claim 3 , further comprising:
a controller operatively coupled to the sensor system and configured to:
receive the fluid properties determined by the sensor system,
determine an operational efficiency of the heat exchanger based on the received fluid properties, and
generate flow control signals based on the operational efficiency, the flow control signals representing a quantity of the working fluid to be flowed into or out of the heat exchanger; and

a flow control system operatively coupled to the controller and configured to:
receive the flow control signals, and
control a flow of the working fluid into or out of the heat exchanger based on the received flow control signals.

5. The geothermal well completion of claim 1 , wherein the surface portion comprises a power plant disposed at the surface, the power plant configured to:
receive the working fluid at the second temperature and in the second state; and
generate the work using the received working fluid.

6. The geothermal well completion of claim 5 , wherein the surface portion further comprises a solar thermal energy system disposed at the surface, the solar thermal energy system configured to harness solar energy to heat the working fluid at the surface before the working fluid is received by the power plant.

Assignees

• Saudi Arabian Oil Co

Inventors

• Alharbi Atallah N
• Al-Otaibi Mashari

Classifications

• F24T2010/56

  Control arrangements · CPC title

• F24T2010/53

  Methods for installation · CPC title

• Y02E10/10

  Geothermal energy · CPC title

• F24T10/30

  using underground reservoirs for accumulating working fluids or intermediate fluids · CPC title

• E21B41/00 Primary

  Equipment or details not covered by groups E21B15/00 - E21B40/00 · CPC title