Homocentric squares-shaped well structure for marine hydrate reserve recovery utilizing geothermal heat and method thereof

Patent metadata

Field	Value
Publication number	US-10267129-B1
Application number	US-201816058623-A
Country	US
Kind code	B1
Filing date	Aug 8, 2018
Priority date	May 14, 2018
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

The present invention relates to the field of marine hydrate reserve recovery technology, and discloses a homocentric squares-shaped well structure for marine hydrate reserve recovery utilizing geothermal heat and a method thereof. The present invention employs a homocentric squares-shaped well structure and utilizes heat-carrying fluid to transfer the energy in a geothermal reservoir to a hydrate reservoir to promote dissociation of natural gas hydrates. The homocentric squares-shaped well structure can realize cyclic utilization of the heat-carrying fluid while improving heat conduction efficiency, and has advantages including high recovery rate, low recovery cost, low energy loss, and high heat utilization efficiency, etc.

First claim

The invention claimed is:

1. A homocentric squares-shaped well structure for marine hydrate reserve recovery utilizing geothermal heat, comprising:
an injection well, arranged to extend from the ocean surface to a geothermal reservoir and configured to inject heat-carrying fluid;
a heat extraction well, disposed inside the geothermal reservoir and configured to convey the heat-carrying fluid so that the heat-carrying fluid extracts heat from the geothermal reservoir, an inlet end of the heat extraction well being in communication with an outlet end of the injection well;
a circulation well, arranged to extend from the geothermal reservoir to a hydrate reservoir, an inlet end of the circulation well being in communication with an outlet end of the heat extraction well;
a heat release and collection well, disposed in the hydrate reservoir and configured to release the heat-carrying fluid to the hydrate reservoir and collect dissociation products in the hydrate reservoir at the same time, an inlet end of the heat release and collection well being in communication with an outlet end of the circulation well; and
a production pipeline, fitted in the injection well, wherein a radial clearance is formed between the production pipeline and the injection well, the production pipeline is arranged to extend from the ocean surface to the hydrate reservoir, an inlet end of the production pipeline extends out of the injection well and is in communication with an outlet end of the heat release and collection well, a gas-liquid separator is disposed in the production pipeline and is configured to block the direct communication between the inlet end and the outlet end of the production pipeline, an inlet of the gas-liquid separator is in communication with the inlet end of the production pipeline, a liquid outlet of the gas-liquid separator is in communication with the injection well, and a gas outlet of the gas-liquid separator is in communication with the outlet end of the production pipeline.

2. The homocentric squares-shaped well structure of claim 1 , wherein a check valve is configured to prevent the gas from flowing back into the gas-liquid separator and is disposed in the production pipeline.

3. The homocentric squares-shaped well structure of claim 1 , wherein the injection well and the circulation well are vertical wells.

4. The homocentric squares-shaped well structure of claim 3 , wherein a central axis of the heat release and collection well is at a distance equal to ⅓-¼ of a thickness of the hydrate reservoir from a top surface of the hydrate reservoir.

5. The homocentric squares-shaped well structure of claim 1 , wherein the heat extraction well and the heat release and collection well are horizontal wells.

6. The homocentric squares-shaped well structure of claim 5 , wherein a central axis of the heat release and collection well is at a distance equal to ⅓-¼ of a thickness of the hydrate reservoir from a top surface of the hydrate reservoir.

7. The homocentric squares-shaped well structure of claim 1 , wherein the heat extraction well and the heat release and collection well are both screen pipes.

8. The homocentric squares-shaped well structure of claim 1 , wherein the homocentric squares-shaped well structure comprises a pressurizing device configured to provide circulation power for the heat-carrying fluid.

9. The homocentric squares-shaped well structure of claim 1 , comprising an ocean platform disposed above the injection well, wherein the ocean platform is equipped with a processing station in communication with the outlet end of the production pipeline and a natural gas recovery bunker in communication with the processing station.

10. The homocentric squares-shaped well structure of claim 1 , wherein an intermediate formation exists between the hydrate reservoir and the geothermal reservoir, and an insulating sleeve is fitted over the portion of the circulation well in the intermediate formation.

11. A method for marine hydrate reserve recovery utilizing geothermal heat, comprising the following steps:
S1: injecting heat-carrying fluid into a geothermal reservoir, and driving the heat-carrying fluid to extract heat from the geothermal reservoir and then flow to a hydrate reservoir, to promote dissociation of natural gas hydrates in the hydrate reservoir;
S2: treating the dissociation product in the hydrate reservoir by gas-liquid separation, recovering the gas product, injecting the liquid product into the geothermal reservoir so that the liquid product is circulated with the heat-carrying fluid as in step S1,
the method is implemented in a homocentric squares-shaped well structure for marine hydrate reserve recovery utilizing geothermal heat, comprising:
an injection well, arranged to extend from the ocean surface to a geothermal reservoir and configured to inject heat-carrying fluid;
a heat extraction well, disposed inside the geothermal reservoir and configured to convey the heat-carrying fluid so that the heat-carrying fluid extracts heat from the geothermal reservoir, an inlet end of the heat extraction well being in communication with an outlet end of the injection well;
a circulation well, arranged to extend from the geothermal reservoir to a hydrate reservoir, an inlet end of the circulation well being in communication with an outlet end of the heat extraction well;
a heat release and collection well, disposed in the hydrate reservoir and configured to release the heat-carrying fluid to the hydrate reservoir and collect dissociation products in the hydrate reservoir at the same time, an inlet end of the heat release and collection well being in communication with an outlet end of the circulation well; and
a production pipeline, fitted in the injection well, wherein a radial clearance is formed between the production pipeline and the injection well, the production pipeline is arranged to extend from the ocean surface to the hydrate reservoir, an inlet end of the production pipeline extends out of the injection well and is in communication with an outlet end of the heat release and collection well, a gas-liquid separator is disposed in the production pipeline and is configured to block the direct communication between the inlet end and the outlet end of the production pipeline, an inlet of the gas-liquid separator is in communication with the inlet end of the production pipeline, a liquid outlet of the gas-liquid separator is in communication with the injection well, and a gas outlet of the gas-liquid separator is in communication with the outlet end of the production pipeline.

12. The method of claim 11 , wherein, the step S2 further comprises transferring the heat carried by the gas product to the heat-carrying fluid to be injected into the geothermal reservoir in the gas product recovery process.

Assignees

• Univ China Petroleum East China

Inventors

• Sun Baojiang
• Chen Ye
• Wang Zhiyuan
• Chen Litao
• Gao Yonghai
• Xu Jiafang
• Zhang Heen

Classifications

• E21B43/305 Primary

  comprising at least one inclined or horizontal well · CPC title

• E21B43/24 Primary

  using heat, e.g. steam injection · CPC title

• E21B41/0099

  specially adapted for drilling for or production of natural hydrate or clathrate gas reservoirs; Drilling through or monitoring of formations containing gas hydrates or clathrates · CPC title

• E21B43/01

  specially adapted for obtaining from underwater installations · CPC title

• E21B34/06

  in wells · CPC title