Method of extracting underground resources and hydrolysis-blocking agent for use in the method

Patent metadata

Field	Value
Publication number	US-10487620-B2
Application number	US-201515527223-A
Country	US
Kind code	B2
Filing date	Oct 22, 2015
Priority date	Nov 19, 2014
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

A method of extracting the underground resources by pressurizing a fluid filled in an ore chute in which cracks are formed and by, further, forming or growing the cracks, the underground resources being extracted through the cracks, wherein a hydrolysis-blocking agent is introduced with pressure into the fluid to block a diverting agent that works to temporarily close the cracks.

First claim

The invention claimed is:

1. A method of extracting underground resources by pressurizing a fluid filled in an ore chute in which cracks are formed and by, further, forming or growing the cracks, the underground resources being extracted through the cracks,
wherein a hydrolysis-blocking agent is introduced with pressure into the fluid to block a diverting agent that works to temporarily close the cracks,
wherein the hydrolysis-blocking agent is a hydrolysable resin having a glass transition temperature (Tg) lower than a temperature in an environment of extraction and a crystallization index ΔHm of not more than 70 J/g, the crystallization index ΔHm being found from a curve of temperature rise measured in the first time by using a DSC and being represented by the following formula (1),
Δ Hm=ΔHm′−ΔHc   (1)

wherein ΔHm′ is a quantity of heat of fusion (J/g) calculated from a peak area of an endothermic peak of fusion, and
ΔHc is a quantity of heat (J/g) calculated from a peak area of an exothermic peak of crystallization.

2. The method of extraction according to claim 1 , wherein the hydrolysis-blocking agent is introduced together with the diverting agent with pressure into the fluid.

3. The method of extraction according to claim 1 , wherein after the cracks have been closed at least partly with the diverting agent, the hydrolysis-blocking agent is introduced with pressure into the fluid.

4. The method of extraction according to claim 1 , wherein an aliphatic polyester is used as the diverting agent.

5. A hydrolysis-blocking agent to be added to a fluid that is filled in an ore chute, the hydrolysis-blocking agent having a crystallization index ΔHm of not more than 70 J/g, the crystallization index ΔHm being found from a curve of temperature rise measured in the first time by using a DSC and being represented by the following formula (1),
Δ Hm=ΔHm′−ΔHc   (1)

wherein ΔHm′ is a quantity of heat of fusion (J/g) calculated from a peak area of an endothermic peak of fusion, and
ΔHc is a quantity of heat (J/g) calculated from a peak area of an exothermic peak of crystallization,
wherein the hydrolysis-blocking agent is a copolymerized polyoxalate in which a dibasic acid unit other than an oxalic acid has been introduced.

6. A method of extracting underground resources by pressurizing a fluid filled in an ore chute in which cracks are formed and by, further, forming or growing the cracks, the underground resources being extracted through the cracks,
wherein a hydrolysis-blocking agent is introduced with pressure into the fluid to block a diverting agent that works to temporarily close the cracks,
wherein the hydrolysis-blocking agent is a hydrolysable resin having a glass transition temperature (Tg) lower than a temperature in an environment of extraction and a crystallization index ΔHm of not more than 70 J/g, the crystallization index ΔHm being found from a curve of temperature rise measured in the first time by using a DSC and being represented by the following formula (1),
Δ Hm=ΔHm′−ΔHc   (1)

wherein ΔHm′ is a quantity of heat of fusion (J/g) calculated from a peak area of an endothermic peak of fusion, and
ΔHc is a quantity of heat (J/g) calculated from a peak area of an exothermic peak of crystallization, and
wherein the hydrolysis-blocking agent is a copolymerized polyoxalate in which a dibasic acid unit other than an oxalic acid has been introduced.

7. The method of extraction according to claim 6 , wherein the hydrolysis-blocking agent is introduced together with the diverting agent with pressure into the fluid.

8. The method of extraction according to claim 6 , wherein after the cracks have been closed at least partly with the diverting agent, the hydrolysis-blocking agent is introduced with pressure into the fluid.

9. The method of extraction according to claim 6 , wherein an aliphatic polyester is used as the diverting agent.

10. A method of extracting underground resources by pressurizing a fluid filled in an ore chute in which cracks are formed and by, further, forming or growing the cracks, the underground resources being extracted through the cracks,
wherein a hydrolysis-blocking agent is introduced with pressure into the fluid to block a diverting agent that works to temporarily close the cracks, and
wherein an aliphatic polyester is used as the diverting agent.

11. The method of extraction according to claim 10 , wherein a hydrolysable resin having a glass transition temperature (Tg) lower than a temperature in an environment of extraction is used as the hydrolysis-blocking agent.

12. The method of extraction according to claim 11 , wherein the hydrolysable resin used as the hydrolysis-blocking agent has a glass transition temperature (Tg) lower than a temperature in an environment of extraction and a crystallization index ΔHm of not more than 70 J/g, the crystallization index ΔHm being found from a curve of temperature rise measured in the first time by using a DSC and being represented by the following formula (1),
Δ Hm=ΔHm′−ΔHc   (1)

wherein ΔHm′ is a quantity of heat of fusion (J/g) calculated from a peak area of an endothermic peak of fusion, and
ΔHc is a quantity of heat (J/g) calculated from a peak area of an exothermic peak of crystallization.

13. The method of extraction according to claim 12 , wherein the hydrolysis-blocking agent is a copolymerized polyoxalate in which a dibasic acid unit other than an oxalic acid has been introduced.

14. The method of extraction according to claim 10 , wherein the hydrolysis-blocking agent is introduced together with the diverting agent with pressure into the fluid.

15. The method of extraction according to claim 10 , wherein after the cracks have been closed at least partly with the diverting agent, the hydrolysis-blocking agent is introduced with pressure into the fluid.

Assignees

• Toyo Seikan Group Holdings Ltd

Inventors

• Yoshikawa Seishi
• Katayama Tsutaki

Classifications

• C09K8/80

  Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open · CPC title

• E21B43/267

  reinforcing fractures by propping · CPC title

• E21B21/003

  Means for stopping loss of drilling fluid (plastering the borehole wall E21B33/138) · CPC title

• E21B33/143 Primary

  for underwater installations · CPC title

• E21B43/26

  by forming crevices or fractures · CPC title